Merge branch 'master' of https://github.com/eugenp/tutorials

algorithms-searching/src/main/java/com/baeldung/algorithms/suffixtree/Node.java

@@ -0,0 +1,57 @@
+package com.baeldung.algorithms.suffixtree;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Node {
+    private String text;
+    private List<Node> children;
+    private int position;
+
+    public Node(String word, int position) {
+        this.text = word;
+        this.position = position;
+        this.children = new ArrayList<>();
+    }
+
+    public String getText() {
+        return text;
+    }
+
+    public void setText(String text) {
+        this.text = text;
+    }
+
+    public int getPosition() {
+        return position;
+    }
+
+    public void setPosition(int position) {
+        this.position = position;
+    }
+
+    public List<Node> getChildren() {
+        return children;
+    }
+
+    public void setChildren(List<Node> children) {
+        this.children = children;
+    }
+
+    public String printTree(String depthIndicator) {
+        String str = "";
+        String positionStr = position > -1 ? "[" + String.valueOf(position) + "]" : "";
+        str += depthIndicator + text + positionStr + "\n";
+
+        for (int i = 0; i < children.size(); i++) {
+            str += children.get(i)
+                .printTree(depthIndicator + "\t");
+        }
+        return str;
+    }
+
+    @Override
+    public String toString() {
+        return printTree("");
+    }
+}

algorithms-searching/src/main/java/com/baeldung/algorithms/suffixtree/SuffixTree.java

@@ -0,0 +1,175 @@
+package com.baeldung.algorithms.suffixtree;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class SuffixTree {
+    private static final Logger LOGGER = LoggerFactory.getLogger(SuffixTree.class);
+    private static final String WORD_TERMINATION = "$";
+    private static final int POSITION_UNDEFINED = -1;
+    private Node root;
+    private String fullText;
+
+    public SuffixTree(String text) {
+        root = new Node("", POSITION_UNDEFINED);
+        for (int i = 0; i < text.length(); i++) {
+            addSuffix(text.substring(i) + WORD_TERMINATION, i);
+        }
+        fullText = text;
+    }
+
+    public List<String> searchText(String pattern) {
+        LOGGER.info("Searching for pattern \"{}\"", pattern);
+        List<String> result = new ArrayList<>();
+        List<Node> nodes = getAllNodesInTraversePath(pattern, root, false);
+
+        if (nodes.size() > 0) {
+            Node lastNode = nodes.get(nodes.size() - 1);
+            if (lastNode != null) {
+                List<Integer> positions = getPositions(lastNode);
+                positions = positions.stream()
+                    .sorted()
+                    .collect(Collectors.toList());
+                positions.forEach(m -> result.add((markPatternInText(m, pattern))));
+            }
+        }
+        return result;
+    }
+
+    private void addSuffix(String suffix, int position) {
+        LOGGER.info(">>>>>>>>>>>> Adding new suffix {}", suffix);
+        List<Node> nodes = getAllNodesInTraversePath(suffix, root, true);
+        if (nodes.size() == 0) {
+            addChildNode(root, suffix, position);
+            LOGGER.info("{}", printTree());
+        } else {
+            Node lastNode = nodes.remove(nodes.size() - 1);
+            String newText = suffix;
+            if (nodes.size() > 0) {
+                String existingSuffixUptoLastNode = nodes.stream()
+                    .map(a -> a.getText())
+                    .reduce("", String::concat);
+
+                // Remove prefix from newText already included in parent
+                newText = newText.substring(existingSuffixUptoLastNode.length());
+            }
+            extendNode(lastNode, newText, position);
+            LOGGER.info("{}", printTree());
+        }
+    }
+
+    private List<Integer> getPositions(Node node) {
+        List<Integer> positions = new ArrayList<>();
+        if (node.getText()
+            .endsWith(WORD_TERMINATION)) {
+            positions.add(node.getPosition());
+        }
+        for (int i = 0; i < node.getChildren()
+            .size(); i++) {
+            positions.addAll(getPositions(node.getChildren()
+                .get(i)));
+        }
+        return positions;
+    }
+
+    private String markPatternInText(Integer startPosition, String pattern) {
+        String matchingTextLHS = fullText.substring(0, startPosition);
+        String matchingText = fullText.substring(startPosition, startPosition + pattern.length());
+        String matchingTextRHS = fullText.substring(startPosition + pattern.length());
+        return matchingTextLHS + "[" + matchingText + "]" + matchingTextRHS;
+    }
+
+    private void addChildNode(Node parentNode, String text, int position) {
+        parentNode.getChildren()
+            .add(new Node(text, position));
+    }
+
+    private void extendNode(Node node, String newText, int position) {
+        String currentText = node.getText();
+        String commonPrefix = getLongestCommonPrefix(currentText, newText);
+
+        if (commonPrefix != currentText) {
+            String parentText = currentText.substring(0, commonPrefix.length());
+            String childText = currentText.substring(commonPrefix.length());
+            splitNodeToParentAndChild(node, parentText, childText);
+        }
+
+        String remainingText = newText.substring(commonPrefix.length());
+        addChildNode(node, remainingText, position);
+    }
+
+    private void splitNodeToParentAndChild(Node parentNode, String parentNewText, String childNewText) {
+        Node childNode = new Node(childNewText, parentNode.getPosition());
+
+        if (parentNode.getChildren()
+            .size() > 0) {
+            while (parentNode.getChildren()
+                .size() > 0) {
+                childNode.getChildren()
+                    .add(parentNode.getChildren()
+                        .remove(0));
+            }
+        }
+
+        parentNode.getChildren()
+            .add(childNode);
+        parentNode.setText(parentNewText);
+        parentNode.setPosition(POSITION_UNDEFINED);
+    }
+
+    private String getLongestCommonPrefix(String str1, String str2) {
+        int compareLength = Math.min(str1.length(), str2.length());
+        for (int i = 0; i < compareLength; i++) {
+            if (str1.charAt(i) != str2.charAt(i)) {
+                return str1.substring(0, i);
+            }
+        }
+        return str1.substring(0, compareLength);
+    }
+
+    private List<Node> getAllNodesInTraversePath(String pattern, Node startNode, boolean isAllowPartialMatch) {
+        List<Node> nodes = new ArrayList<>();
+        for (int i = 0; i < startNode.getChildren()
+            .size(); i++) {
+            Node currentNode = startNode.getChildren()
+                .get(i);
+            String nodeText = currentNode.getText();
+            if (pattern.charAt(0) == nodeText.charAt(0)) {
+                if (isAllowPartialMatch && pattern.length() <= nodeText.length()) {
+                    nodes.add(currentNode);
+                    return nodes;
+                }
+
+                int compareLength = Math.min(nodeText.length(), pattern.length());
+                for (int j = 1; j < compareLength; j++) {
+                    if (pattern.charAt(j) != nodeText.charAt(j)) {
+                        if (isAllowPartialMatch) {
+                            nodes.add(currentNode);
+                        }
+                        return nodes;
+                    }
+                }
+
+                nodes.add(currentNode);
+                if (pattern.length() > compareLength) {
+                    List<Node> nodes2 = getAllNodesInTraversePath(pattern.substring(compareLength), currentNode, isAllowPartialMatch);
+                    if (nodes2.size() > 0) {
+                        nodes.addAll(nodes2);
+                    } else if (!isAllowPartialMatch) {
+                        nodes.add(null);
+                    }
+                }
+                return nodes;
+            }
+        }
+        return nodes;
+    }
+
+    public String printTree() {
+        return root.printTree("");
+    }
+}

algorithms-searching/src/test/java/com/baeldung/algorithms/suffixtree/SuffixTreeUnitTest.java

@@ -0,0 +1,77 @@
+package com.baeldung.algorithms.suffixtree;
+
+import java.util.List;
+
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class SuffixTreeUnitTest {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(SuffixTreeUnitTest.class);
+
+    private static SuffixTree suffixTree;
+
+    @BeforeClass
+    public static void setUp() {
+        suffixTree = new SuffixTree("havanabanana");
+        printTree();
+    }
+
+    @Test
+    public void givenSuffixTree_whenSearchingForA_thenReturn6Matches() {
+        List<String> matches = suffixTree.searchText("a");
+        matches.stream()
+            .forEach(m -> LOGGER.info(m));
+        Assert.assertArrayEquals(new String[] { "h[a]vanabanana", "hav[a]nabanana", "havan[a]banana", "havanab[a]nana", "havanaban[a]na", "havanabanan[a]" }, matches.toArray());
+    }
+
+    @Test
+    public void givenSuffixTree_whenSearchingForNab_thenReturn1Match() {
+        List<String> matches = suffixTree.searchText("nab");
+        matches.stream()
+            .forEach(m -> LOGGER.info(m));
+        Assert.assertArrayEquals(new String[] { "hava[nab]anana" }, matches.toArray());
+    }
+
+    @Test
+    public void givenSuffixTree_whenSearchingForNag_thenReturnNoMatches() {
+        List<String> matches = suffixTree.searchText("nag");
+        matches.stream()
+            .forEach(m -> LOGGER.info(m));
+        Assert.assertArrayEquals(new String[] {}, matches.toArray());
+    }
+
+    @Test
+    public void givenSuffixTree_whenSearchingForBanana_thenReturn2Matches() {
+        List<String> matches = suffixTree.searchText("ana");
+        matches.stream()
+            .forEach(m -> LOGGER.info(m));
+        Assert.assertArrayEquals(new String[] { "hav[ana]banana", "havanab[ana]na", "havanaban[ana]" }, matches.toArray());
+    }
+
+    @Test
+    public void givenSuffixTree_whenSearchingForNa_thenReturn4Matches() {
+        List<String> matches = suffixTree.searchText("na");
+        matches.stream()
+            .forEach(m -> LOGGER.info(m));
+        Assert.assertArrayEquals(new String[] { "hava[na]banana", "havanaba[na]na", "havanabana[na]" }, matches.toArray());
+    }
+
+    @Test
+    public void givenSuffixTree_whenSearchingForX_thenReturnNoMatches() {
+        List<String> matches = suffixTree.searchText("x");
+        matches.stream()
+            .forEach(m -> LOGGER.info(m));
+        Assert.assertArrayEquals(new String[] {}, matches.toArray());
+    }
+
+    private static void printTree() {
+        suffixTree.printTree();
+
+        LOGGER.info("\n" + suffixTree.printTree());
+        LOGGER.info("==============================================");
+    }
+}

core-java-modules/core-java-nio-2/src/main/java/com/baeldung/lock/FileLocks.java

@@ -0,0 +1,148 @@
+package com.baeldung.lock;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.RandomAccessFile;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.channels.FileLock;
+import java.nio.channels.NonReadableChannelException;
+import java.nio.channels.NonWritableChannelException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
+
+public class FileLocks {
+
+    private static final Logger LOG = LoggerFactory.getLogger(FileLocks.class);
+
+    // Write locks
+
+    /**
+     * Trying to get an exclusive lock on a read-only FileChannel won't work.
+     */
+    static void getExclusiveLockFromInputStream() throws IOException {
+        Path path = Files.createTempFile("foo", "txt");
+        try (FileInputStream fis = new FileInputStream(path.toFile());
+            FileLock lock = fis.getChannel()
+                .lock()) {
+            LOG.debug("This won't happen");
+        } catch (NonWritableChannelException e) {
+            LOG.error("The channel obtained through a FileInputStream isn't writable. You can't obtain an exclusive lock on it!");
+            throw e;
+        }
+    }
+
+    /**
+     * Gets an exclusive lock from a RandomAccessFile. Works because the file is writable.
+     * @param from beginning of the locked region
+     * @param size how many bytes to lock
+     * @return A lock object representing the newly-acquired lock
+     * @throws IOException if there is a problem creating the temporary file
+     */
+    static FileLock getExclusiveLockFromRandomAccessFile(long from, long size) throws IOException {
+        Path path = Files.createTempFile("foo", "txt");
+        try (RandomAccessFile file = new RandomAccessFile(path.toFile(), "rw");
+            FileLock lock = file.getChannel()
+                .lock(from, size, false)) {
+            if (lock.isValid()) {
+                LOG.debug("This is a valid exclusive lock");
+                return lock;
+            }
+            return null;
+        } catch (Exception e) {
+            LOG.error(e.getMessage());
+        }
+        return null;
+    }
+
+    /**
+     * Acquires an exclusive lock on a file region.
+     * @param from beginning of the locked region
+     * @param size how many bytes to lock
+     * @return A lock object representing the newly-acquired lock
+     * @throws IOException if there is a problem creating the temporary file
+     */
+    static FileLock getExclusiveLockFromFileChannelOpen(long from, long size) throws IOException {
+        Path path = Files.createTempFile("foo", "txt");
+        try (FileChannel channel = FileChannel.open(path, StandardOpenOption.APPEND); FileLock lock = channel.lock(from, size, false)) {
+            String text = "Hello, world.";
+            ByteBuffer buffer = ByteBuffer.allocate(text.length() + System.lineSeparator()
+                .length());
+            buffer.put((text + System.lineSeparator()).getBytes(StandardCharsets.UTF_8));
+            buffer.flip();
+            while (buffer.hasRemaining()) {
+                channel.write(buffer, channel.size());
+            }
+            LOG.debug("This was written to the file");
+            Files.lines(path)
+                .forEach(LOG::debug);
+            return lock;
+        }
+    }
+
+    // Read locks
+
+    /**
+     * Trying to get a shared lock on a write-only FileChannel won't work.
+     */
+    static void getReadLockFromOutputStream() throws IOException {
+        Path path = Files.createTempFile("foo", "txt");
+        try (FileOutputStream fis = new FileOutputStream(path.toFile());
+            FileLock lock = fis.getChannel()
+                .lock(0, Long.MAX_VALUE, true)) {
+            LOG.debug("This won't happen");
+        } catch (NonReadableChannelException e) {
+            LOG.error("The channel obtained through a FileOutputStream isn't readable. " + "You can't obtain an shared lock on it!");
+            throw e;
+        }
+    }
+
+    /**
+     * Gets a lock from an <tt>InputStream</tt>.
+     * @param from beginning of the locked region
+     * @param size how many bytes to lock
+     * @return A lock object representing the newly-acquired lock
+     * @throws IOException if there is a problem creating the temporary file
+     */
+    static FileLock getReadLockFromInputStream(long from, long size) throws IOException {
+        Path path = Files.createTempFile("foo", "txt");
+        try (FileInputStream fis = new FileInputStream(path.toFile());
+            FileLock lock = fis.getChannel()
+                .lock(from, size, true)) {
+            if (lock.isValid()) {
+                LOG.debug("This is a valid shared lock");
+                return lock;
+            }
+            return null;
+        }
+    }
+
+    /**
+     * Gets an exclusive lock from a RandomAccessFile. Works because the file is readable.
+     * @param from beginning of the locked region
+     * @param size how many bytes to lock
+     * @return A lock object representing the newly-acquired lock
+     * @throws IOException if there is a problem creating the temporary file
+     */
+    static FileLock getReadLockFromRandomAccessFile(long from, long size) throws IOException {
+        Path path = Files.createTempFile("foo", "txt");
+        try (RandomAccessFile file = new RandomAccessFile(path.toFile(), "r"); // could also be "rw", but "r" is sufficient for reading
+            FileLock lock = file.getChannel()
+                .lock(from, size, true)) {
+            if (lock.isValid()) {
+                LOG.debug("This is a valid shared lock");
+                return lock;
+            }
+        } catch (Exception e) {
+            LOG.error(e.getMessage());
+        }
+        return null;
+    }
+
+}

core-java-modules/core-java-nio-2/src/test/java/com/baeldung/lock/FileLocksUnitTest.java

@@ -0,0 +1,54 @@
+package com.baeldung.lock;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.IOException;
+import java.nio.channels.FileLock;
+import java.nio.channels.NonReadableChannelException;
+import java.nio.channels.NonWritableChannelException;
+
+import org.junit.jupiter.api.Test;
+
+class FileLocksUnitTest {
+
+    @Test
+    void givenAnInputStream_whenGetWriteLock_thenThrowNonWritableChannelException() {
+        assertThrows(NonWritableChannelException.class, () -> FileLocks.getExclusiveLockFromInputStream());
+    }
+
+    @Test
+    void givenARandomAccessFileWithReadWriteAccess_whenGetWriteLock_thenLock() throws IOException {
+        FileLock lock = FileLocks.getExclusiveLockFromRandomAccessFile(0, 10);
+        assertNotNull(lock);
+        assertFalse(lock.isShared());
+    }
+
+    @Test
+    void givenAPath_whenGetExclusiveLock_thenLock() throws IOException {
+        FileLock lock = FileLocks.getExclusiveLockFromFileChannelOpen(0, 10);
+        assertNotNull(lock);
+        assertFalse(lock.isShared());
+    }
+
+    @Test
+    void givenAFileOutputStream_whenGetSharedLock_thenThrowNonReadableChannelException() {
+        assertThrows(NonReadableChannelException.class, FileLocks::getReadLockFromOutputStream);
+    }
+
+    @Test
+    void givenAnInputStream_whenGetSharedLock_thenLock() throws IOException {
+        FileLock lock = FileLocks.getReadLockFromInputStream(0, 10);
+        assertNotNull(lock);
+        assertTrue(lock.isShared());
+    }
+
+    @Test
+    void givenARandomAccessFile_whenGetSharedLock_thenLock() throws IOException {
+        FileLock lock = FileLocks.getReadLockFromRandomAccessFile(0, 10);
+        assertNotNull(lock);
+        assertTrue(lock.isShared());
+    }
+}

core-java-modules/core-java/README.md

@@ -11,7 +11,7 @@
 - [Introduction to Java Serialization](http://www.baeldung.com/java-serialization)
 - [Guide to UUID in Java](http://www.baeldung.com/java-uuid)
 - [Creating a Java Compiler Plugin](http://www.baeldung.com/java-build-compiler-plugin)
-- [Quick Guide to Java Stack](http://www.baeldung.com/java-stack)
+- [Quick Guide to the Java Stack](http://www.baeldung.com/java-stack)
 - [Compiling Java *.class Files with javac](http://www.baeldung.com/javac)
 - [Introduction to Javadoc](http://www.baeldung.com/javadoc)
 - [Guide to the Externalizable Interface in Java](http://www.baeldung.com/java-externalizable)

core-java-modules/core-java/src/test/java/com/baeldung/timer/JavaTimerLongRunningUnitTest.java

@@ -1,4 +1,4 @@
-package com.baeldung;
+package com.baeldung.timer;
 
 import org.junit.Test;
 import org.slf4j.Logger;

core-kotlin-modules/core-kotlin-2/README.md

@@ -5,4 +5,5 @@ This module contains articles about Kotlin core features.
 ### Relevant articles:
 - [Working with Dates in Kotlin](https://www.baeldung.com/kotlin-dates)
 - [Kotlin Ternary Conditional Operator](https://www.baeldung.com/kotlin-ternary-operator)
+- [Sequences in Kotlin](https://www.baeldung.com/kotlin/sequences)
 - [[<-- Prev]](/core-kotlin-modules/core-kotlin)

core-kotlin-modules/core-kotlin/README.md

@@ -13,4 +13,7 @@ This module contains articles about Kotlin core features.
 - [Implementing a Binary Tree in Kotlin](https://www.baeldung.com/kotlin-binary-tree)
 - [JUnit 5 for Kotlin Developers](https://www.baeldung.com/junit-5-kotlin)
 - [Converting Kotlin Data Class from JSON using GSON](https://www.baeldung.com/kotlin-json-convert-data-class)
+- [Fuel HTTP Library with Kotlin](https://www.baeldung.com/kotlin-fuel)
+- [Introduction to Kovenant Library for Kotlin](https://www.baeldung.com/kotlin-kovenant)
+- [Dependency Injection for Kotlin with Injekt](https://www.baeldung.com/kotlin-dependency-injection-with-injekt)
 - [[More --> ]](/core-kotlin-modules/core-kotlin-2)

core-scala/README.md

@@ -5,3 +5,4 @@ This module contains articles about Scala's core features
 ### Relevant Articles: 
 
 - [Introduction to Scala](https://www.baeldung.com/scala-intro)
+- [Regular Expressions in Scala](https://www.baeldung.com/scala/regular-expressions)

core-scala/src/test/scala/com/baeldung/scala/HigherOrderFunctionsExamplesUnitTest.scala

@@ -0,0 +1,82 @@
+package com.baeldung.scala
+
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+
+class HigherOrderFunctionsExamplesUnitTest {
+
+  @Test
+  def whenCallingMapWithAnonymousFunction_thenTransformationIsApplied() = {
+    val expected = Seq("sir Alex Ferguson", "sir Bobby Charlton", "sir Frank Lampard")
+
+    val names = Seq("Alex Ferguson", "Bobby Charlton", "Frank Lampard")
+    val sirNames = names.map(name => "sir " + name)
+
+    assertEquals(expected, sirNames)
+  }
+
+  @Test
+  def whenCallingMapWithDefined_thenTransformationIsApplied() = {
+    val expected = Seq("sir Alex Ferguson", "sir Bobby Charlton", "sir Frank Lampard")
+
+    val names = Seq("Alex Ferguson", "Bobby Charlton", "Frank Lampard")
+
+    def prefixWithSir(name: String) = "sir " + name
+    val sirNames = names.map(prefixWithSir)
+
+    assertEquals(expected, sirNames)
+  }
+
+  @Test
+  def whenCallingFilter_thenUnecessaryElementsAreRemoved() = {
+    val expected = Seq("John O'Shea", "John Hartson")
+
+    val names = Seq("John O'Shea", "Aiden McGeady", "John Hartson")
+    val johns = names.filter(name => name.matches("^John .*"))
+
+    assertEquals(expected, johns)
+  }
+
+  @Test
+  def whenCallingReduce_thenProperSumIsCalculated() = {
+    val expected = 2750
+
+    val earnings = Seq(1000, 1300, 450)
+    val sumEarnings = earnings.reduce((acc, x) => acc + x)
+
+    assertEquals(expected, sumEarnings)
+  }
+
+  @Test
+  def whenCallingFold_thenNumberOfWordsShouldBeCalculated() = {
+    val expected = 6
+
+    val strings = Seq("bunch of words", "just me", "it")
+    val sumEarnings = strings.foldLeft(0)((acc, x) => acc + x.split(" ").size)
+
+    assertEquals(expected, sumEarnings)
+  }
+
+  @Test
+  def whenCallingOwnHigherOrderFunction_thenProperFunctionIsReturned() = {
+    def mathOperation(name: String): (Int, Int) => Int = (x: Int, y: Int) => {
+      name match {
+        case "addition" => x + y
+        case "multiplication" => x * y
+        case "division" => x/y
+        case "subtraction" => x - y
+      }
+    }
+
+    def add: (Int, Int) => Int = mathOperation("addition")
+    def mul: (Int, Int) => Int = mathOperation("multiplication")
+    def div: (Int, Int) => Int = mathOperation("division")
+    def sub: (Int, Int) => Int = mathOperation("subtraction")
+
+    assertEquals(15, add(10, 5))
+    assertEquals(50, mul(10, 5))
+    assertEquals(2, div(10, 5))
+    assertEquals(5, sub(10, 5))
+  }
+}

core-scala/src/test/scala/com/baeldung/scala/regex/RegexUnitTest.scala

@@ -1,4 +1,4 @@
-package com.baeldung.scala
+package com.baeldung.scala.regex
 
 import org.junit.Test
 import org.junit.Assert.assertEquals

ddd-modules/README.md

@@ -0,0 +1 @@
+## Relevant Articles

ddd-modules/infrastructure/pom.xml

@@ -0,0 +1,53 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.dddmodules.infrastructure</groupId>
+    <artifactId>infrastructure</artifactId>
+    <version>1.0</version>
+
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.dddmodules</groupId>
+        <artifactId>dddmodules</artifactId>
+        <version>1.0</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.baeldung.dddmodules.shippingcontext</groupId>
+            <artifactId>shippingcontext</artifactId>
+            <version>${appmodules.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.baeldung.dddmodules.ordercontext</groupId>
+            <artifactId>ordercontext</artifactId>
+            <version>${appmodules.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.baeldung.dddmodules.sharedkernel</groupId>
+            <artifactId>sharedkernel</artifactId>
+            <version>${appmodules.version}</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>${source.version}</source>
+                    <target>${target.version}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <source.version>9</source.version>
+        <target.version>9</target.version>
+    </properties>
+
+</project>

ddd-modules/infrastructure/src/main/java/com/baeldung/dddmodules/infrastructure/db/InMemoryOrderStore.java

@@ -0,0 +1,79 @@
+package com.baeldung.dddmodules.infrastructure.db;
+
+import com.baeldung.dddmodules.ordercontext.model.CustomerOrder;
+import com.baeldung.dddmodules.ordercontext.repository.CustomerOrderRepository;
+import com.baeldung.dddmodules.shippingcontext.model.PackageItem;
+import com.baeldung.dddmodules.shippingcontext.model.ShippableOrder;
+import com.baeldung.dddmodules.shippingcontext.repository.ShippingOrderRepository;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.stream.Collectors;
+
+public class InMemoryOrderStore implements CustomerOrderRepository, ShippingOrderRepository {
+    private Map<Integer, PersistenceOrder> ordersDb = new HashMap<>();
+    private volatile static InMemoryOrderStore instance = new InMemoryOrderStore();
+
+    @Override
+    public void saveCustomerOrder(CustomerOrder order) {
+        this.ordersDb.put(order.getOrderId(), new PersistenceOrder(order.getOrderId(),
+          order.getPaymentMethod(),
+          order.getAddress(),
+          order
+            .getOrderItems()
+            .stream()
+            .map(orderItem ->
+              new PersistenceOrder.OrderItem(orderItem.getProductId(),
+                orderItem.getQuantity(),
+                orderItem.getUnitWeight(),
+                orderItem.getUnitPrice()))
+            .collect(Collectors.toList())
+        ));
+    }
+
+    @Override
+    public Optional<ShippableOrder> findShippableOrder(int orderId) {
+        if (!this.ordersDb.containsKey(orderId)) return Optional.empty();
+        PersistenceOrder orderRecord = this.ordersDb.get(orderId);
+        return Optional.of(
+          new ShippableOrder(orderRecord.orderId, orderRecord.orderItems
+            .stream().map(orderItem -> new PackageItem(orderItem.productId,
+              orderItem.itemWeight,
+              orderItem.quantity * orderItem.unitPrice)
+            ).collect(Collectors.toList())));
+    }
+
+    public static InMemoryOrderStore provider() {
+        return instance;
+    }
+
+    public static class PersistenceOrder {
+        public int orderId;
+        public String paymentMethod;
+        public String address;
+        public List<OrderItem> orderItems;
+
+        public PersistenceOrder(int orderId, String paymentMethod, String address, List<OrderItem> orderItems) {
+            this.orderId = orderId;
+            this.paymentMethod = paymentMethod;
+            this.address = address;
+            this.orderItems = orderItems;
+        }
+
+        public static class OrderItem {
+            public int productId;
+            public float unitPrice;
+            public float itemWeight;
+            public int quantity;
+
+            public OrderItem(int productId, int quantity, float unitWeight, float unitPrice) {
+                this.itemWeight = unitWeight;
+                this.quantity = quantity;
+                this.unitPrice = unitPrice;
+                this.productId = productId;
+            }
+        }
+    }
+}

ddd-modules/infrastructure/src/main/java/com/baeldung/dddmodules/infrastructure/events/SimpleEventBus.java

@@ -0,0 +1,39 @@
+package com.baeldung.dddmodules.infrastructure.events;
+
+import com.baeldung.dddmodules.sharedkernel.events.ApplicationEvent;
+import com.baeldung.dddmodules.sharedkernel.events.EventBus;
+import com.baeldung.dddmodules.sharedkernel.events.EventSubscriber;
+
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CopyOnWriteArraySet;
+
+public class SimpleEventBus implements EventBus {
+    private final Map<String, Set<EventSubscriber>> subscribers = new ConcurrentHashMap<>();
+
+    @Override
+    public <E extends ApplicationEvent> void publish(E event) {
+        if (subscribers.containsKey(event.getType())) {
+            subscribers.get(event.getType())
+              .forEach(subscriber -> subscriber.onEvent(event));
+        }
+    }
+
+    @Override
+    public <E extends ApplicationEvent> void subscribe(String eventType, EventSubscriber subscriber) {
+        Set<EventSubscriber> eventSubscribers = subscribers.get(eventType);
+        if (eventSubscribers == null) {
+            eventSubscribers = new CopyOnWriteArraySet<>();
+            subscribers.put(eventType, eventSubscribers);
+        }
+        eventSubscribers.add(subscriber);
+    }
+
+    @Override
+    public <E extends ApplicationEvent> void unsubscribe(String eventType, EventSubscriber subscriber) {
+        if (subscribers.containsKey(eventType)) {
+            subscribers.get(eventType).remove(subscriber);
+        }
+    }
+}

ddd-modules/infrastructure/src/main/java/module-info.java

@@ -0,0 +1,11 @@
+module com.baeldung.dddmodules.infrastructure {
+    requires transitive com.baeldung.dddmodules.sharedkernel;
+    requires transitive com.baeldung.dddmodules.ordercontext;
+    requires transitive com.baeldung.dddmodules.shippingcontext;
+    provides com.baeldung.dddmodules.sharedkernel.events.EventBus
+      with com.baeldung.dddmodules.infrastructure.events.SimpleEventBus;
+    provides com.baeldung.dddmodules.ordercontext.repository.CustomerOrderRepository
+      with com.baeldung.dddmodules.infrastructure.db.InMemoryOrderStore;
+    provides com.baeldung.dddmodules.shippingcontext.repository.ShippingOrderRepository
+      with com.baeldung.dddmodules.infrastructure.db.InMemoryOrderStore;
+}

ddd-modules/mainapp/pom.xml

@@ -0,0 +1,51 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.dddmodules.mainapp</groupId>
+    <artifactId>mainapp</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.dddmodules</groupId>
+        <artifactId>dddmodules</artifactId>
+        <version>1.0</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.baeldung.dddmodules.infrastructure</groupId>
+            <artifactId>infrastructure</artifactId>
+            <version>${appmodules.version}</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-surefire-plugin</artifactId>
+                <version>2.16</version>
+                <configuration>
+                    <enableAssertions>true</enableAssertions>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>${compiler.plugin.version}</version>
+                <configuration>
+                    <source>${source.version}</source>
+                    <target>${target.version}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <source.version>9</source.version>
+        <target.version>9</target.version>
+    </properties>
+
+</project>

ddd-modules/mainapp/src/main/java/com/baeldung/dddmodules/mainapp/Application.java

@@ -0,0 +1,54 @@
+package com.baeldung.dddmodules.mainapp;
+
+import com.baeldung.dddmodules.ordercontext.model.CustomerOrder;
+import com.baeldung.dddmodules.ordercontext.model.OrderItem;
+import com.baeldung.dddmodules.ordercontext.repository.CustomerOrderRepository;
+import com.baeldung.dddmodules.ordercontext.service.OrderService;
+import com.baeldung.dddmodules.sharedkernel.events.EventBus;
+import com.baeldung.dddmodules.shippingcontext.repository.ShippingOrderRepository;
+import com.baeldung.dddmodules.shippingcontext.service.ShippingService;
+
+import java.util.*;
+
+public class Application {
+
+    public static void main(String args[]) {
+        Map<Class<?>, Object> container = createContainer();
+        OrderService orderService = (OrderService) container.get(OrderService.class);
+        ShippingService shippingService = (ShippingService) container.get(ShippingService.class);
+        shippingService.listenToOrderEvents();
+
+        CustomerOrder customerOrder = new CustomerOrder();
+        int orderId = 1;
+        customerOrder.setOrderId(orderId);
+        List<OrderItem> orderItems = new ArrayList<OrderItem>();
+        orderItems.add(new OrderItem(1, 2, 3, 1));
+        orderItems.add(new OrderItem(2, 1, 1, 1));
+        orderItems.add(new OrderItem(3, 4, 11, 21));
+        customerOrder.setOrderItems(orderItems);
+        customerOrder.setPaymentMethod("PayPal");
+        customerOrder.setAddress("Full address here");
+        orderService.placeOrder(customerOrder);
+
+        if (orderId == shippingService.getParcelByOrderId(orderId).get().getOrderId()) {
+            System.out.println("Order has been processed and shipped successfully");
+        }
+    }
+
+    public static Map<Class<?>, Object> createContainer() {
+        EventBus eventBus = ServiceLoader.load(EventBus.class).findFirst().get();
+        CustomerOrderRepository customerOrderRepository = ServiceLoader.load(CustomerOrderRepository.class).findFirst().get();
+        ShippingOrderRepository shippingOrderRepository = ServiceLoader.load(ShippingOrderRepository.class).findFirst().get();
+        ShippingService shippingService = ServiceLoader.load(ShippingService.class).findFirst().get();
+        shippingService.setEventBus(eventBus);
+        shippingService.setOrderRepository(shippingOrderRepository);
+        OrderService orderService = ServiceLoader.load(OrderService.class).findFirst().get();
+        orderService.setEventBus(eventBus);
+        orderService.setOrderRepository(customerOrderRepository);
+        HashMap<Class<?>, Object> container = new HashMap<>();
+        container.put(OrderService.class, orderService);
+        container.put(ShippingService.class, shippingService);
+        return container;
+    }
+
+}

ddd-modules/mainapp/src/main/java/module-info.java

@@ -0,0 +1,8 @@
+module com.baeldung.dddmodules.mainapp {
+    uses com.baeldung.dddmodules.sharedkernel.events.EventBus;
+    uses com.baeldung.dddmodules.ordercontext.service.OrderService;
+    uses com.baeldung.dddmodules.ordercontext.repository.CustomerOrderRepository;
+    uses com.baeldung.dddmodules.shippingcontext.repository.ShippingOrderRepository;
+    uses com.baeldung.dddmodules.shippingcontext.service.ShippingService;
+    requires transitive com.baeldung.dddmodules.infrastructure;
+}

ddd-modules/ordercontext/pom.xml

@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.dddmodules.ordercontext</groupId>
+    <artifactId>ordercontext</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.dddmodules</groupId>
+        <artifactId>dddmodules</artifactId>
+        <version>1.0</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.baeldung.dddmodules.sharedkernel</groupId>
+            <artifactId>sharedkernel</artifactId>
+            <version>${appmodules.version}</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>${source.version}</source>
+                    <target>${target.version}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <source.version>9</source.version>
+        <target.version>9</target.version>
+        <entitymodule.version>1.0</entitymodule.version>
+        <daomodule.version>1.0</daomodule.version>
+    </properties>
+
+</project>

ddd-modules/ordercontext/src/main/java/com/baeldung/dddmodules/ordercontext/model/CustomerOrder.java

@@ -0,0 +1,51 @@
+package com.baeldung.dddmodules.ordercontext.model;
+
+import java.util.List;
+
+public class CustomerOrder {
+    private int orderId;
+    private String paymentMethod;
+    private String address;
+    private List<OrderItem> orderItems;
+
+    public CustomerOrder() {
+
+    }
+
+    public float calculateTotalPrice() {
+        return orderItems.stream().map(OrderItem::getTotalPrice)
+          .reduce(0F, Float::sum);
+    }
+
+    public void setOrderItems(List<OrderItem> orderItems) {
+        this.orderItems = orderItems;
+    }
+
+    public int getOrderId() {
+        return orderId;
+    }
+
+    public List<OrderItem> getOrderItems() {
+        return orderItems;
+    }
+
+    public void setOrderId(int orderId) {
+        this.orderId = orderId;
+    }
+
+    public String getPaymentMethod() {
+        return paymentMethod;
+    }
+
+    public void setPaymentMethod(String paymentMethod) {
+        this.paymentMethod = paymentMethod;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+    }
+}

ddd-modules/ordercontext/src/main/java/com/baeldung/dddmodules/ordercontext/model/OrderItem.java

@@ -0,0 +1,51 @@
+package com.baeldung.dddmodules.ordercontext.model;
+
+public class OrderItem {
+    private int productId;
+    private int quantity;
+    private float unitPrice;
+    private float unitWeight;
+
+    public OrderItem(int productId, int quantity, float unitPrice, float unitWeight) {
+        this.productId = productId;
+        this.quantity = quantity;
+        this.unitPrice = unitPrice;
+        this.unitWeight = unitWeight;
+    }
+
+    public int getProductId() {
+        return productId;
+    }
+
+    public void setProductId(int productId) {
+        this.productId = productId;
+    }
+
+    public int getQuantity() {
+        return quantity;
+    }
+
+    public void setQuantity(int quantity) {
+        this.quantity = quantity;
+    }
+
+    public float getTotalPrice() {
+        return this.quantity * this.unitPrice;
+    }
+
+    public void setUnitPrice(float unitPrice) {
+        this.unitPrice = unitPrice;
+    }
+
+    public float getUnitWeight() {
+        return unitWeight;
+    }
+
+    public float getUnitPrice() {
+        return unitPrice;
+    }
+
+    public void setUnitWeight(float unitWeight) {
+        this.unitWeight = unitWeight;
+    }
+}

ddd-modules/ordercontext/src/main/java/com/baeldung/dddmodules/ordercontext/repository/CustomerOrderRepository.java

@@ -0,0 +1,7 @@
+package com.baeldung.dddmodules.ordercontext.repository;
+
+import com.baeldung.dddmodules.ordercontext.model.CustomerOrder;
+
+public interface CustomerOrderRepository {
+    void saveCustomerOrder(CustomerOrder order);
+}

ddd-modules/ordercontext/src/main/java/com/baeldung/dddmodules/ordercontext/service/CustomerOrderService.java

@@ -0,0 +1,44 @@
+package com.baeldung.dddmodules.ordercontext.service;
+
+import com.baeldung.dddmodules.ordercontext.model.CustomerOrder;
+import com.baeldung.dddmodules.ordercontext.repository.CustomerOrderRepository;
+import com.baeldung.dddmodules.sharedkernel.events.ApplicationEvent;
+import com.baeldung.dddmodules.sharedkernel.events.EventBus;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class CustomerOrderService implements OrderService {
+    public static final String EVENT_ORDER_READY_FOR_SHIPMENT = "OrderReadyForShipmentEvent";
+
+    private CustomerOrderRepository orderRepository;
+    private EventBus eventBus;
+
+    @Override
+    public void placeOrder(CustomerOrder order) {
+        this.orderRepository.saveCustomerOrder(order);
+        Map<String, String> payload = new HashMap<>();
+        payload.put("order_id", String.valueOf(order.getOrderId()));
+        ApplicationEvent event = new ApplicationEvent(payload) {
+            @Override
+            public String getType() {
+                return EVENT_ORDER_READY_FOR_SHIPMENT;
+            }
+        };
+        this.eventBus.publish(event);
+    }
+
+    @Override
+    public EventBus getEventBus() {
+        return eventBus;
+    }
+
+    public void setOrderRepository(CustomerOrderRepository orderRepository) {
+        this.orderRepository = orderRepository;
+    }
+
+    @Override
+    public void setEventBus(EventBus eventBus) {
+        this.eventBus = eventBus;
+    }
+}

ddd-modules/ordercontext/src/main/java/com/baeldung/dddmodules/ordercontext/service/OrderService.java

@@ -0,0 +1,11 @@
+package com.baeldung.dddmodules.ordercontext.service;
+
+import com.baeldung.dddmodules.ordercontext.model.CustomerOrder;
+import com.baeldung.dddmodules.ordercontext.repository.CustomerOrderRepository;
+import com.baeldung.dddmodules.sharedkernel.service.ApplicationService;
+
+public interface OrderService extends ApplicationService {
+    void placeOrder(CustomerOrder order);
+
+    void setOrderRepository(CustomerOrderRepository orderRepository);
+}

ddd-modules/ordercontext/src/main/java/module-info.java

@@ -0,0 +1,8 @@
+module com.baeldung.dddmodules.ordercontext {
+    requires com.baeldung.dddmodules.sharedkernel;
+    exports com.baeldung.dddmodules.ordercontext.service;
+    exports com.baeldung.dddmodules.ordercontext.model;
+    exports com.baeldung.dddmodules.ordercontext.repository;
+    provides com.baeldung.dddmodules.ordercontext.service.OrderService
+      with com.baeldung.dddmodules.ordercontext.service.CustomerOrderService;
+}

ddd-modules/pom.xml

@@ -0,0 +1,68 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.dddmodules</groupId>
+    <artifactId>dddmodules</artifactId>
+    <version>1.0</version>
+    <name>ddd-modules</name>
+    <packaging>pom</packaging>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>parent-modules</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>../</relativePath>
+    </parent>
+
+    <modules>
+        <module>sharedkernel</module>
+        <module>infrastructure</module>
+        <module>shippingcontext</module>
+        <module>ordercontext</module>
+        <module>mainapp</module>
+    </modules>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>junit</groupId>
+                <artifactId>junit</artifactId>
+                <version>${junit.version}</version>
+                <scope>test</scope>
+            </dependency>
+            <dependency>
+                <groupId>org.assertj</groupId>
+                <artifactId>assertj-core</artifactId>
+                <version>${assertj-core.version}</version>
+                <scope>test</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>org.apache.maven.plugins</groupId>
+                    <artifactId>maven-compiler-plugin</artifactId>
+                    <version>${compiler.plugin.version}</version>
+                    <configuration>
+                        <source>${source.version}</source>
+                        <target>${target.version}</target>
+                    </configuration>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
+    <properties>
+        <compiler.plugin.version>3.8.1</compiler.plugin.version>
+        <source.version>9</source.version>
+        <target.version>9</target.version>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <assertj-core.version>3.12.2</assertj-core.version>
+        <appmodules.version>1.0</appmodules.version>
+    </properties>
+
+</project>

ddd-modules/sharedkernel/pom.xml

@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.dddmodules.sharedkernel</groupId>
+    <artifactId>sharedkernel</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.dddmodules</groupId>
+        <artifactId>dddmodules</artifactId>
+        <version>1.0</version>
+    </parent>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>${source.version}</source>
+                    <target>${target.version}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <source.version>9</source.version>
+        <target.version>9</target.version>
+    </properties>
+
+</project>

ddd-modules/sharedkernel/src/main/java/com/baeldung/dddmodules/sharedkernel/events/ApplicationEvent.java

@@ -0,0 +1,21 @@
+package com.baeldung.dddmodules.sharedkernel.events;
+
+import java.util.Map;
+
+public abstract class ApplicationEvent {
+    protected Map<String, String> payload;
+
+    public abstract String getType();
+
+    public String getPayloadValue(String key) {
+        if (this.payload.containsKey(key)) {
+            return this.payload.get(key);
+        }
+        return "";
+    }
+
+    public ApplicationEvent(Map<String, String> payload) {
+        this.payload = payload;
+    }
+}
+

ddd-modules/sharedkernel/src/main/java/com/baeldung/dddmodules/sharedkernel/events/EventBus.java

@@ -0,0 +1,9 @@
+package com.baeldung.dddmodules.sharedkernel.events;
+
+public interface EventBus {
+    <E extends ApplicationEvent> void publish(E event);
+
+    <E extends ApplicationEvent> void subscribe(String eventType, EventSubscriber subscriber);
+
+    <E extends ApplicationEvent> void unsubscribe(String eventType, EventSubscriber subscriber);
+}

ddd-modules/sharedkernel/src/main/java/com/baeldung/dddmodules/sharedkernel/events/EventSubscriber.java

@@ -0,0 +1,5 @@
+package com.baeldung.dddmodules.sharedkernel.events;
+
+public interface EventSubscriber {
+    <E extends ApplicationEvent> void onEvent(E event);
+}

ddd-modules/sharedkernel/src/main/java/com/baeldung/dddmodules/sharedkernel/service/ApplicationService.java

@@ -0,0 +1,33 @@
+package com.baeldung.dddmodules.sharedkernel.service;
+
+import com.baeldung.dddmodules.sharedkernel.events.ApplicationEvent;
+import com.baeldung.dddmodules.sharedkernel.events.EventBus;
+import com.baeldung.dddmodules.sharedkernel.events.EventSubscriber;
+
+public interface ApplicationService {
+
+    default <E extends ApplicationEvent> void publishEvent(E event) {
+        EventBus eventBus = getEventBus();
+        if (eventBus != null) {
+            eventBus.publish(event);
+        }
+    }
+
+    default <E extends ApplicationEvent> void subscribe(String eventType, EventSubscriber subscriber) {
+        EventBus eventBus = getEventBus();
+        if (eventBus != null) {
+            eventBus.subscribe(eventType, subscriber);
+        }
+    }
+
+    default <E extends ApplicationEvent> void unsubscribe(String eventType, EventSubscriber subscriber) {
+        EventBus eventBus = getEventBus();
+        if (eventBus != null) {
+            eventBus.unsubscribe(eventType, subscriber);
+        }
+    }
+
+    EventBus getEventBus();
+
+    void setEventBus(EventBus eventBus);
+}

ddd-modules/sharedkernel/src/main/java/module-info.java

@@ -0,0 +1,4 @@
+module com.baeldung.dddmodules.sharedkernel {
+    exports com.baeldung.dddmodules.sharedkernel.events;
+    exports com.baeldung.dddmodules.sharedkernel.service;
+}

ddd-modules/shippingcontext/pom.xml

@@ -0,0 +1,42 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.dddmodules.shippingcontext</groupId>
+    <artifactId>shippingcontext</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.dddmodules</groupId>
+        <artifactId>dddmodules</artifactId>
+        <version>1.0</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>com.baeldung.dddmodules.sharedkernel</groupId>
+            <artifactId>sharedkernel</artifactId>
+            <version>${appmodules.version}</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>${source.version}</source>
+                    <target>${target.version}</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+
+    <properties>
+        <source.version>9</source.version>
+        <target.version>9</target.version>
+    </properties>
+
+</project>

ddd-modules/shippingcontext/src/main/java/com/baeldung/dddmodules/shippingcontext/model/PackageItem.java

@@ -0,0 +1,37 @@
+package com.baeldung.dddmodules.shippingcontext.model;
+
+public class PackageItem {
+    private int productId;
+    private float weight;
+    private float estimatedValue;
+
+    public PackageItem(int productId, float weight, float estimatedValue) {
+        this.productId = productId;
+        this.weight = weight;
+        this.estimatedValue = estimatedValue;
+    }
+
+    public int getProductId() {
+        return productId;
+    }
+
+    public void setProductId(int productId) {
+        this.productId = productId;
+    }
+
+    public float getWeight() {
+        return weight;
+    }
+
+    public void setWeight(float weight) {
+        this.weight = weight;
+    }
+
+    public float getEstimatedValue() {
+        return estimatedValue;
+    }
+
+    public void setEstimatedValue(float estimatedValue) {
+        this.estimatedValue = estimatedValue;
+    }
+}

ddd-modules/shippingcontext/src/main/java/com/baeldung/dddmodules/shippingcontext/model/Parcel.java

@@ -0,0 +1,54 @@
+package com.baeldung.dddmodules.shippingcontext.model;
+
+import java.util.List;
+
+public class Parcel {
+    private int orderId;
+    private String address;
+    private String trackingId;
+    private List<PackageItem> packageItems;
+
+    public Parcel(int orderId, String address, List<PackageItem> packageItems) {
+        this.orderId = orderId;
+        this.address = address;
+        this.packageItems = packageItems;
+    }
+
+    public float calculateTotalWeight() {
+        return packageItems.stream().map(PackageItem::getWeight)
+          .reduce(0F, Float::sum);
+    }
+
+    public boolean isTaxable() {
+        return calculateEstimatedValue() > 100;
+    }
+
+    public float calculateEstimatedValue() {
+        return packageItems.stream().map(PackageItem::getWeight)
+          .reduce(0F, Float::sum);
+    }
+
+    public int getOrderId() {
+        return orderId;
+    }
+
+    public void setOrderId(int orderId) {
+        this.orderId = orderId;
+    }
+
+    public String getTrackingId() {
+        return trackingId;
+    }
+
+    public void setTrackingId(String trackingId) {
+        this.trackingId = trackingId;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+    }
+}

ddd-modules/shippingcontext/src/main/java/com/baeldung/dddmodules/shippingcontext/model/ShippableOrder.java

@@ -0,0 +1,38 @@
+package com.baeldung.dddmodules.shippingcontext.model;
+
+import java.util.List;
+
+public class ShippableOrder {
+    private int orderId;
+    private String address;
+    private List<PackageItem> packageItems;
+
+    public ShippableOrder(int orderId, List<PackageItem> packageItems) {
+        this.orderId = orderId;
+        this.packageItems = packageItems;
+    }
+
+    public int getOrderId() {
+        return orderId;
+    }
+
+    public void setOrderId(int orderId) {
+        this.orderId = orderId;
+    }
+
+    public List<PackageItem> getPackageItems() {
+        return packageItems;
+    }
+
+    public void setPackageItems(List<PackageItem> packageItems) {
+        this.packageItems = packageItems;
+    }
+
+    public String getAddress() {
+        return address;
+    }
+
+    public void setAddress(String address) {
+        this.address = address;
+    }
+}

ddd-modules/shippingcontext/src/main/java/com/baeldung/dddmodules/shippingcontext/repository/ShippingOrderRepository.java

@@ -0,0 +1,9 @@
+package com.baeldung.dddmodules.shippingcontext.repository;
+
+import com.baeldung.dddmodules.shippingcontext.model.ShippableOrder;
+
+import java.util.Optional;
+
+public interface ShippingOrderRepository {
+    Optional<ShippableOrder> findShippableOrder(int orderId);
+}

ddd-modules/shippingcontext/src/main/java/com/baeldung/dddmodules/shippingcontext/service/ParcelShippingService.java

@@ -0,0 +1,63 @@
+package com.baeldung.dddmodules.shippingcontext.service;
+
+import com.baeldung.dddmodules.sharedkernel.events.ApplicationEvent;
+import com.baeldung.dddmodules.sharedkernel.events.EventBus;
+import com.baeldung.dddmodules.sharedkernel.events.EventSubscriber;
+import com.baeldung.dddmodules.shippingcontext.model.Parcel;
+import com.baeldung.dddmodules.shippingcontext.model.ShippableOrder;
+import com.baeldung.dddmodules.shippingcontext.repository.ShippingOrderRepository;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+
+public class ParcelShippingService implements ShippingService {
+    public static final String EVENT_ORDER_READY_FOR_SHIPMENT = "OrderReadyForShipmentEvent";
+    private ShippingOrderRepository orderRepository;
+    private EventBus eventBus;
+    private Map<Integer, Parcel> shippedParcels = new HashMap<>();
+
+    @Override
+    public void shipOrder(int orderId) {
+        Optional<ShippableOrder> order = this.orderRepository.findShippableOrder(orderId);
+        order.ifPresent(completedOrder -> {
+            Parcel parcel = new Parcel(completedOrder.getOrderId(), completedOrder.getAddress(), completedOrder.getPackageItems());
+            if (parcel.isTaxable()) {
+                // Calculate additional taxes
+            }
+            // Ship parcel
+            this.shippedParcels.put(completedOrder.getOrderId(), parcel);
+        });
+    }
+
+    @Override
+    public void listenToOrderEvents() {
+        this.eventBus.subscribe(EVENT_ORDER_READY_FOR_SHIPMENT, new EventSubscriber() {
+            @Override
+            public <E extends ApplicationEvent> void onEvent(E event) {
+                shipOrder(Integer.parseInt(event.getPayloadValue("order_id")));
+            }
+        });
+    }
+
+    @Override
+    public Optional<Parcel> getParcelByOrderId(int orderId) {
+        return Optional.ofNullable(this.shippedParcels.get(orderId));
+    }
+
+    public void setOrderRepository(ShippingOrderRepository orderRepository) {
+        this.orderRepository = orderRepository;
+    }
+
+    @Override
+    public EventBus getEventBus() {
+        return eventBus;
+    }
+
+    @Override
+    public void setEventBus(EventBus eventBus) {
+        this.eventBus = eventBus;
+    }
+
+
+}

ddd-modules/shippingcontext/src/main/java/com/baeldung/dddmodules/shippingcontext/service/ShippingService.java

@@ -0,0 +1,17 @@
+package com.baeldung.dddmodules.shippingcontext.service;
+
+import com.baeldung.dddmodules.sharedkernel.service.ApplicationService;
+import com.baeldung.dddmodules.shippingcontext.model.Parcel;
+import com.baeldung.dddmodules.shippingcontext.repository.ShippingOrderRepository;
+
+import java.util.Optional;
+
+public interface ShippingService extends ApplicationService {
+    void shipOrder(int orderId);
+
+    void listenToOrderEvents();
+
+    Optional<Parcel> getParcelByOrderId(int orderId);
+
+    void setOrderRepository(ShippingOrderRepository orderRepository);
+}

ddd-modules/shippingcontext/src/main/java/module-info.java

@@ -0,0 +1,8 @@
+module com.baeldung.dddmodules.shippingcontext {
+    requires com.baeldung.dddmodules.sharedkernel;
+    exports com.baeldung.dddmodules.shippingcontext.service;
+    exports com.baeldung.dddmodules.shippingcontext.model;
+    exports com.baeldung.dddmodules.shippingcontext.repository;
+    provides com.baeldung.dddmodules.shippingcontext.service.ShippingService
+      with com.baeldung.dddmodules.shippingcontext.service.ParcelShippingService;
+}

gradle/gradle-to-maven/build.gradle

@@ -0,0 +1,41 @@
+repositories {
+    mavenCentral()
+}
+
+apply plugin: 'java'
+apply plugin: 'maven'
+
+group = 'com.baeldung'
+
+// by default, pom's artifactId is taken from the directory name
+
+version = '0.0.1-SNAPSHOT'
+
+dependencies {
+    compile('org.slf4j:slf4j-api')
+    testCompile('junit:junit')
+}
+
+install {
+    repositories {
+        mavenInstaller {
+            pom.version = '0.0.1-maven-SNAPSHOT'
+            pom.groupId = 'com.baeldung.sample'
+            pom.artifactId = 'gradle-maven-converter'
+            pom.project {
+                inceptionYear '2020'
+                licenses {
+                    license {
+                        name 'My License'
+                        url 'http://www.mycompany.com/licenses/license.txt'
+                        distribution 'repo'
+                    }
+                }
+            }
+            pom.whenConfigured {pom ->
+                pom.dependencies.find {dep -> dep.groupId == 'junit' && dep.artifactId == 'junit' }.optional = true
+            }
+            pom.writeTo("${mavenPomDir}/${project.group}/${project.name}/pom.xml")
+        }
+    }
+}

intelliJ/remote-debugging/.idea/runConfigurations/Remote_Debugger.xml

@@ -1,15 +0,0 @@
-<component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="Remote Debugger" type="Remote">
-    <option name="USE_SOCKET_TRANSPORT" value="true" />
-    <option name="SERVER_MODE" value="false" />
-    <option name="SHMEM_ADDRESS" />
-    <option name="HOST" value="localhost" />
-    <option name="PORT" value="5005" />
-    <option name="AUTO_RESTART" value="false" />
-    <RunnerSettings RunnerId="Debug">
-      <option name="DEBUG_PORT" value="5005" />
-      <option name="LOCAL" value="false" />
-    </RunnerSettings>
-    <method v="2" />
-  </configuration>
-</component>

intelliJ/remote-debugging/CONTRIBUTING.adoc

@@ -1,2 +0,0 @@
-If you have not previously done so, please fill out and
-submit the https://cla.pivotal.io/sign/spring[Contributor License Agreement].

intelliJ/remote-debugging/LICENSE.code.txt

@@ -1,16 +0,0 @@
-   All code in this repository is:
-   =======================================================================
-   Copyright (c) 2013 GoPivotal, Inc. All Rights Reserved
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       https://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-

intelliJ/remote-debugging/LICENSE.writing.txt

@@ -1 +0,0 @@
-Except where otherwise noted, this work is licensed under https://creativecommons.org/licenses/by-nd/3.0/

intelliJ/remote-debugging/README.md

@@ -1,3 +0,0 @@
-### Relevant Articles:
-
-- [Remote Debugging with IntelliJ IDEA](https://www.baeldung.com/intellij-remote-debugging)

intelliJ/remote-debugging/pom.xml

@@ -1,50 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
-    <modelVersion>4.0.0</modelVersion>
-
-    <groupId>com.baeldung</groupId>
-    <artifactId>gs-scheduling-tasks</artifactId>
-    <version>0.1.0</version>
-    <name>gs-scheduling-tasks</name>
-
-    <parent>
-        <groupId>com.baeldung</groupId>
-        <artifactId>parent-boot-2</artifactId>
-        <version>0.0.1-SNAPSHOT</version>
-        <relativePath>../../parent-boot-2</relativePath>
-    </parent>
-
-    <properties>
-        <java.version>1.8</java.version>
-        <awaitility.version>3.1.2</awaitility.version>
-        <spring-boot.version>2.1.6.RELEASE</spring-boot.version>
-    </properties>
-
-    <dependencies>
-        <dependency>
-            <groupId>org.springframework.boot</groupId>
-            <artifactId>spring-boot-starter</artifactId>
-        </dependency>
-        <dependency>
-            <groupId>org.springframework.boot</groupId>
-            <artifactId>spring-boot-starter-test</artifactId>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.awaitility</groupId>
-            <artifactId>awaitility</artifactId>
-            <version>${awaitility.version}</version>
-            <scope>test</scope>
-        </dependency>
-    </dependencies>
-
-    <build>
-        <plugins>
-            <plugin>
-                <groupId>org.springframework.boot</groupId>
-                <artifactId>spring-boot-maven-plugin</artifactId>
-            </plugin>
-        </plugins>
-    </build>
-</project>

intelliJ/remote-debugging/src/main/java/hello/ScheduledTasks.java

@@ -1,38 +0,0 @@
-/*
- * Copyright 2012-2015 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package hello;
-
-import java.text.SimpleDateFormat;
-import java.util.Date;
-
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-import org.springframework.scheduling.annotation.Scheduled;
-import org.springframework.stereotype.Component;
-
-@Component
-public class ScheduledTasks {
-
-    private static final Logger log = LoggerFactory.getLogger(ScheduledTasks.class);
-
-    private static final SimpleDateFormat dateFormat = new SimpleDateFormat("HH:mm:ss");
-
-    @Scheduled(fixedRate = 5000)
-    public void reportCurrentTime() {
-        log.info("The time is now {}", dateFormat.format(new Date()));
-    }
-}

libraries-3/README.md

@@ -11,3 +11,4 @@ Remember, for advanced libraries like [Jackson](/jackson) and [JUnit](/testing-m
 - [Parsing Command-Line Parameters with JCommander](https://www.baeldung.com/jcommander-parsing-command-line-parameters)
 - [Guide to the Cactoos Library](https://www.baeldung.com/java-cactoos)
 - [Parsing Command-Line Parameters with Airline](https://www.baeldung.com/java-airline)
+- [Introduction to cache2k](https://www.baeldung.com/java-cache2k)

libraries-3/pom.xml

@@ -73,6 +73,28 @@
             <version>${cache2k.version}</version>
             <type>pom</type>
         </dependency>
+        <dependency>
+            <groupId>com.squareup.moshi</groupId>
+            <artifactId>moshi</artifactId>
+            <version>${moshi.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>com.squareup.moshi</groupId>
+            <artifactId>moshi-adapters</artifactId>
+            <version>${moshi.version}</version>
+        </dependency>
+        
+        <dependency>
+            <groupId>com.jcabi</groupId>
+            <artifactId>jcabi-aspects</artifactId>
+            <version>${jcabi-aspects.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.aspectj</groupId>
+            <artifactId>aspectjrt</artifactId>
+            <version>${aspectjrt.version}</version>
+            <scope>runtime</scope>
+        </dependency>
     </dependencies>
 
     <repositories>
@@ -82,6 +104,36 @@
         </repository>
     </repositories>
     
+    <build>
+        <finalName>libraries-3</finalName>
+        <plugins>
+            <plugin>
+                <groupId>com.jcabi</groupId>
+                <artifactId>jcabi-maven-plugin</artifactId>
+                <version>${jcabi-maven-plugin.version}</version>
+                <executions>
+                    <execution>
+                        <goals>
+                            <goal>ajc</goal>
+                        </goals>
+                    </execution>
+                </executions>
+                <dependencies>
+                    <dependency>
+                        <groupId>org.aspectj</groupId>
+                        <artifactId>aspectjtools</artifactId>
+                        <version>${aspectjtools.version}</version>
+                    </dependency>
+                    <dependency>
+                        <groupId>org.aspectj</groupId>
+                        <artifactId>aspectjweaver</artifactId>
+                        <version>${aspectjweaver.version}</version>
+                    </dependency>
+                </dependencies>
+            </plugin>
+        </plugins>
+    </build>
+
     <properties>
         <jcommander.version>1.78</jcommander.version>
         <lombok.version>1.18.6</lombok.version>
@@ -93,5 +145,11 @@
         <cactoos.version>0.43</cactoos.version>
         <airline.version>2.7.2</airline.version>
         <cache2k.version>1.2.3.Final</cache2k.version>
+        <moshi.version>1.9.2</moshi.version>
+        <jcabi-aspects.version>0.22.6</jcabi-aspects.version>
+        <aspectjrt.version>1.9.2</aspectjrt.version>
+        <jcabi-maven-plugin.version>0.14.1</jcabi-maven-plugin.version>
+        <aspectjtools.version>1.9.2</aspectjtools.version>
+        <aspectjweaver.version>1.9.2</aspectjweaver.version>
     </properties>
 </project>

libraries-3/src/main/java/com/baeldung/cache2k/ProductHelper.java

@@ -4,38 +4,33 @@ import java.util.Objects;
 
 import org.cache2k.Cache;
 import org.cache2k.Cache2kBuilder;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 public class ProductHelper {
 
-    final Logger LOGGER = LoggerFactory.getLogger(ProductHelper.class);
-
     private Cache<String, Integer> cachedDiscounts;
 
+    private int cacheMissCount = 0;
+
     public ProductHelper() {
         cachedDiscounts = Cache2kBuilder.of(String.class, Integer.class)
             .name("discount")
             .eternal(true)
             .entryCapacity(100)
             .build();
-
-        initDiscountCache("Sports", 20);
-    }
-
-    public void initDiscountCache(String productType, Integer value) {
-        cachedDiscounts.put(productType, value);
     }
 
     public Integer getDiscount(String productType) {
         Integer discount = cachedDiscounts.get(productType);
         if (Objects.isNull(discount)) {
-            LOGGER.info("Discount for {} not found.", productType);
+            cacheMissCount++;
-            discount = 0;
+            discount = "Sports".equalsIgnoreCase(productType) ? 20 : 10;
-        } else {
+            cachedDiscounts.put(productType, discount);
-            LOGGER.info("Discount for {} found.", productType);
         }
         return discount;
     }
 
+    public int getCacheMissCount() {
+        return cacheMissCount;
+    }
+
 }

libraries-3/src/main/java/com/baeldung/cache2k/ProductHelperUsingLoader.java

@@ -1,6 +1,5 @@
 package com.baeldung.cache2k;
 
-import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
 import org.cache2k.Cache;
@@ -14,28 +13,26 @@ public class ProductHelperUsingLoader {
 
     private Cache<String, Integer> cachedDiscounts;
 
+    private int cacheMissCount = 0;
+
     public ProductHelperUsingLoader() {
         cachedDiscounts = Cache2kBuilder.of(String.class, Integer.class)
             .name("discount-loader")
-            .eternal(false)
             .expireAfterWrite(10, TimeUnit.MILLISECONDS)
             .entryCapacity(100)
             .loader((key) -> {
-                LOGGER.info("Calculating discount for {}.", key);
+                cacheMissCount++;
                 return "Sports".equalsIgnoreCase(key) ? 20 : 10;
             })
             .build();
     }
 
     public Integer getDiscount(String productType) {
-        Integer discount = cachedDiscounts.get(productType);
+        return cachedDiscounts.get(productType);
-        if (Objects.isNull(discount)) {
-            LOGGER.info("Discount for {} not found.", productType);
-            discount = 0;
-        } else {
-            LOGGER.info("Discount for {} found.", productType);
     }
-        return discount;
+
+    public int getCacheMissCount() {
+        return cacheMissCount;
     }
 
 }

libraries-3/src/main/java/com/baeldung/cache2k/ProductHelperWithEventListener.java

@@ -1,6 +1,5 @@
 package com.baeldung.cache2k;
 
-import java.util.Objects;
 import java.util.concurrent.TimeUnit;
 
 import org.cache2k.Cache;
@@ -16,14 +15,15 @@ public class ProductHelperWithEventListener {
 
     private Cache<String, Integer> cachedDiscounts;
 
+    private int cacheMissCount = 0;
+
     public ProductHelperWithEventListener() {
         cachedDiscounts = Cache2kBuilder.of(String.class, Integer.class)
             .name("discount-listener")
-            .eternal(false)
             .expireAfterWrite(10, TimeUnit.MILLISECONDS)
             .entryCapacity(100)
             .loader((key) -> {
-                LOGGER.info("Calculating discount for {}.", key);
+                cacheMissCount++;
                 return "Sports".equalsIgnoreCase(key) ? 20 : 10;
             })
             .addListener(new CacheEntryCreatedListener<String, Integer>() {
@@ -36,14 +36,11 @@ public class ProductHelperWithEventListener {
     }
 
     public Integer getDiscount(String productType) {
-        Integer discount = cachedDiscounts.get(productType);
+        return cachedDiscounts.get(productType);
-        if (Objects.isNull(discount)) {
-            LOGGER.info("Discount for {} not found.", productType);
-            discount = 0;
-        } else {
-            LOGGER.info("Discount for {} found.", productType);
     }
-        return discount;
+
+    public int getCacheMissCount() {
+        return cacheMissCount;
     }
 
 }

libraries-3/src/main/java/com/baeldung/cache2k/ProductHelperWithExpiry.java

@@ -5,39 +5,34 @@ import java.util.concurrent.TimeUnit;
 
 import org.cache2k.Cache;
 import org.cache2k.Cache2kBuilder;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 public class ProductHelperWithExpiry {
 
-    final Logger LOGGER = LoggerFactory.getLogger(ProductHelperWithExpiry.class);
-
     private Cache<String, Integer> cachedDiscounts;
 
+    private int cacheMissCount = 0;
+
     public ProductHelperWithExpiry() {
         cachedDiscounts = Cache2kBuilder.of(String.class, Integer.class)
             .name("discount-expiry")
-            .eternal(false)
             .expireAfterWrite(5, TimeUnit.MILLISECONDS)
             .entryCapacity(100)
             .build();
 
-        initDiscountCache("Sports", 20);
-    }
-
-    public void initDiscountCache(String productType, Integer value) {
-        cachedDiscounts.put(productType, value);
     }
 
     public Integer getDiscount(String productType) {
         Integer discount = cachedDiscounts.get(productType);
         if (Objects.isNull(discount)) {
-            LOGGER.info("Discount for {} not found.", productType);
+            cacheMissCount++;
-            discount = 0;
+            discount = "Sports".equalsIgnoreCase(productType) ? 20 : 10;
-        } else {
+            cachedDiscounts.put(productType, discount);
-            LOGGER.info("Discount for {} found.", productType);
         }
         return discount;
     }
 
+    public int getCacheMissCount() {
+        return cacheMissCount;
+    }
+
 }

libraries-3/src/main/java/com/baeldung/jcabi/JcabiAspectJ.java

@@ -0,0 +1,112 @@
+package com.baeldung.jcabi;
+
+
+import java.io.BufferedReader;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.net.MalformedURLException;
+import java.net.URL;
+import java.net.URLConnection;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Future;
+import java.util.concurrent.TimeUnit;
+
+import com.jcabi.aspects.Async;
+import com.jcabi.aspects.Cacheable;
+import com.jcabi.aspects.LogExceptions;
+import com.jcabi.aspects.Loggable;
+import com.jcabi.aspects.Quietly;
+import com.jcabi.aspects.RetryOnFailure;
+import com.jcabi.aspects.UnitedThrow;
+
+public class JcabiAspectJ {
+
+    public static void main(String[] args) {
+        try {
+            displayFactorial(10);
+            getFactorial(10).get();
+
+            String result = cacheExchangeRates();
+            if (result != cacheExchangeRates()) {
+                System.out.println(result);
+            }
+
+            divideByZero();
+        } catch(Exception e) {
+            e.printStackTrace();
+        }
+
+        divideByZeroQuietly();
+        try {
+            processFile();  
+        } catch(Exception e) {
+            e.printStackTrace();
+        }
+
+    }
+
+    @Loggable
+    @Async
+    public static void displayFactorial(int number) {
+        long result = factorial(number);
+        System.out.println(result);
+    }
+
+    @Loggable
+    @Async
+    public static Future<Long> getFactorial(int number) {
+        Future<Long> factorialFuture = CompletableFuture.supplyAsync(() -> factorial(number));
+        return factorialFuture;
+    }
+
+    /**
+     * Finds factorial of a number
+     * @param number
+     * @return
+     */
+    public static long factorial(int number) {
+        long result = 1; 
+        for(int i=number;i>0;i--) {
+            result *= i; 
+        } 
+        return result; 
+    }
+
+    @Loggable
+    @Cacheable(lifetime = 2, unit = TimeUnit.SECONDS)
+    public static String cacheExchangeRates() {
+        String result = null;
+        try {
+            URL exchangeRateUrl = new URL("https://api.exchangeratesapi.io/latest");
+            URLConnection con = exchangeRateUrl.openConnection();
+            BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
+            result = in.readLine();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+        return result;
+    }
+
+    @LogExceptions
+    public static void divideByZero() {
+        int x = 1/0;
+    }
+
+    @RetryOnFailure(attempts = 2, types = {java.lang.NumberFormatException.class})
+    @Quietly
+    public static void divideByZeroQuietly() {
+        int x = 1/0;
+    }
+
+    @UnitedThrow(IllegalStateException.class)
+    public static void processFile() throws IOException, InterruptedException {
+        BufferedReader reader = new BufferedReader(new FileReader("baeldung.txt"));
+        reader.readLine();
+        
+        Thread thread = new Thread();
+        thread.wait(2000);
+    }
+
+}

libraries-3/src/test/java/com/baeldung/cache2k/ProductHelperUnitTest.java

@@ -6,12 +6,13 @@ import org.junit.Test;
 
 public class ProductHelperUnitTest {
 
-    ProductHelper productHelper = new ProductHelper();
-
     @Test
-    public void whenInvokedGetDiscount_thenGetItFromCache() {
+    public void whenInvokedGetDiscountTwice_thenGetItFromCache() {
+        ProductHelper productHelper = new ProductHelper();
+        assertTrue(productHelper.getCacheMissCount() == 0);
         assertTrue(productHelper.getDiscount("Sports") == 20);
-        assertTrue(productHelper.getDiscount("Electronics") == 0);
+        assertTrue(productHelper.getDiscount("Sports") == 20);
+        assertTrue(productHelper.getCacheMissCount() == 1);
     }
 
 }

libraries-3/src/test/java/com/baeldung/cache2k/ProductHelperUsingLoaderUnitTest.java

@@ -6,12 +6,16 @@ import org.junit.Test;
 
 public class ProductHelperUsingLoaderUnitTest {
 
-    ProductHelperUsingLoader productHelper = new ProductHelperUsingLoader();
-
     @Test
-    public void whenInvokedGetDiscount_thenPopulateCache() {
+    public void whenInvokedGetDiscount_thenPopulateCacheUsingLoader() {
+        ProductHelperUsingLoader productHelper = new ProductHelperUsingLoader();
+        assertTrue(productHelper.getCacheMissCount() == 0);
+
         assertTrue(productHelper.getDiscount("Sports") == 20);
+        assertTrue(productHelper.getCacheMissCount() == 1);
+
         assertTrue(productHelper.getDiscount("Electronics") == 10);
+        assertTrue(productHelper.getCacheMissCount() == 2);
     }
 
 }

libraries-3/src/test/java/com/baeldung/cache2k/ProductHelperWithEventListenerUnitTest.java

@@ -6,10 +6,9 @@ import org.junit.Test;
 
 public class ProductHelperWithEventListenerUnitTest {
 
-    ProductHelperWithEventListener productHelper = new ProductHelperWithEventListener();
-
     @Test
     public void whenEntryAddedInCache_thenEventListenerCalled() {
+        ProductHelperWithEventListener productHelper = new ProductHelperWithEventListener();
         assertTrue(productHelper.getDiscount("Sports") == 20);
     }
 

libraries-3/src/test/java/com/baeldung/cache2k/ProductHelperWithExpiryUnitTest.java

@@ -6,13 +6,17 @@ import org.junit.Test;
 
 public class ProductHelperWithExpiryUnitTest {
 
-    ProductHelperWithExpiry productHelper = new ProductHelperWithExpiry();
-
     @Test
-    public void whenInvokedGetDiscountForExpiredProduct_thenNoDiscount() throws InterruptedException {
+    public void whenInvokedGetDiscountAfterExpiration_thenDiscountCalculatedAgain() throws InterruptedException {
+        ProductHelperWithExpiry productHelper = new ProductHelperWithExpiry();
+        assertTrue(productHelper.getCacheMissCount() == 0);
         assertTrue(productHelper.getDiscount("Sports") == 20);
+        assertTrue(productHelper.getCacheMissCount() == 1);
+
         Thread.sleep(20);
-        assertTrue(productHelper.getDiscount("Sports") == 0);
+
+        assertTrue(productHelper.getDiscount("Sports") == 20);
+        assertTrue(productHelper.getCacheMissCount() == 2);
     }
 
 }

libraries-3/src/test/java/com/baeldung/moshi/AlternativeAdapterUnitTest.java

@@ -0,0 +1,105 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.time.Instant;
+
+import com.squareup.moshi.FromJson;
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.JsonQualifier;
+import com.squareup.moshi.Moshi;
+import com.squareup.moshi.ToJson;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.Test;
+
+public class AlternativeAdapterUnitTest {
+    @Test
+    public void whenSerializing_thenAlternativeAdapterUsed() {
+        Moshi moshi = new Moshi.Builder()
+          .add(new EpochMillisAdapter())
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = jsonAdapter.toJson(new Post("Introduction to Moshi Json", "Baeldung", Instant.now()));
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenAlternativeAdapterUsed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .add(new EpochMillisAdapter())
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"author\":\"Baeldung\",\"posted\":1582095269204,\"title\":\"Introduction to Moshi Json\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+
+    }
+
+    public static class Post {
+        String title;
+        String author;
+        @EpochMillis Instant posted;
+
+        public Post() {
+        }
+
+        public Post(String title, String author, Instant posted) {
+            this.title = title;
+            this.author = author;
+            this.posted = posted;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        public Instant getPosted() {
+            return posted;
+        }
+
+        public void setPosted(Instant posted) {
+            this.posted = posted;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).append("posted", posted)
+                .toString();
+        }
+    }
+    @Retention(RetentionPolicy.RUNTIME)
+    @Target({ElementType.FIELD, ElementType.PARAMETER, ElementType.METHOD})
+    @JsonQualifier
+    public @interface EpochMillis {
+    }
+
+    public static class EpochMillisAdapter {
+        @ToJson
+        public Long toJson(@EpochMillis Instant input) {
+            return input.toEpochMilli();
+        }
+        @FromJson
+        @EpochMillis
+        public Instant fromJson(Long input) {
+            return Instant.ofEpochMilli(input);
+        }
+
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/ArrayUnitTest.java

@@ -0,0 +1,36 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.lang.reflect.Type;
+import java.util.Arrays;
+import java.util.List;
+
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import com.squareup.moshi.Types;
+import org.junit.Test;
+
+public class ArrayUnitTest {
+    @Test
+    public void whenSerializingList_thenJsonArrayProduced() {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        Type type = Types.newParameterizedType(List.class, String.class);
+        JsonAdapter<List<String>> jsonAdapter = moshi.adapter(type);
+
+        String json = jsonAdapter.toJson(Arrays.asList("One", "Two", "Three"));
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializingJsonArray_thenListProduced() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        Type type = Types.newParameterizedType(List.class, String.class);
+        JsonAdapter<List<String>> jsonAdapter = moshi.adapter(type);
+
+        String json = "[\"One\",\"Two\",\"Three\"]";
+        List<String> result = jsonAdapter.fromJson(json);
+        System.out.println(result);
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/ComplexAdapterUnitTest.java

@@ -0,0 +1,94 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.time.LocalDate;
+import java.time.LocalTime;
+import java.time.ZoneId;
+import java.time.ZonedDateTime;
+
+import com.squareup.moshi.FromJson;
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import com.squareup.moshi.ToJson;
+import org.junit.Test;
+
+public class ComplexAdapterUnitTest {
+    @Test
+    public void whenSerializing_thenCorrectJsonProduced() {
+        Moshi moshi = new Moshi.Builder()
+          .add(new JsonDateTimeAdapter())
+          .build();
+        JsonAdapter<ZonedDateTime> jsonAdapter = moshi.adapter(ZonedDateTime.class);
+
+        String json = jsonAdapter.toJson(ZonedDateTime.now());
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenCorrectJsonConsumed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .add(new JsonDateTimeAdapter())
+          .build();
+        JsonAdapter<ZonedDateTime> jsonAdapter = moshi.adapter(ZonedDateTime.class);
+
+        String json = "{\"date\":\"2020-02-17\",\"time\":\"07:53:27.064\",\"timezone\":\"Europe/London\"}";
+        ZonedDateTime now = jsonAdapter.fromJson(json);
+        System.out.println(now);
+
+    }
+
+    public static class JsonDateTimeAdapter {
+        @ToJson
+        public JsonDateTime toJson(ZonedDateTime input) {
+            String date = input.toLocalDate().toString();
+            String time = input.toLocalTime().toString();
+            String timezone = input.getZone().toString();
+            return new JsonDateTime(date, time, timezone);
+        }
+        @FromJson
+        public ZonedDateTime fromJson(JsonDateTime input) {
+            LocalDate date = LocalDate.parse(input.getDate());
+            LocalTime time = LocalTime.parse(input.getTime());
+            ZoneId timezone = ZoneId.of(input.getTimezone());
+            return ZonedDateTime.of(date, time, timezone);
+        }
+    }
+    public static class JsonDateTime {
+        private String date;
+        private String time;
+        private String timezone;
+
+        public JsonDateTime() {
+        }
+
+        public JsonDateTime(String date, String time, String timezone) {
+            this.date = date;
+            this.time = time;
+            this.timezone = timezone;
+        }
+
+        public String getDate() {
+            return date;
+        }
+
+        public void setDate(String date) {
+            this.date = date;
+        }
+
+        public String getTime() {
+            return time;
+        }
+
+        public void setTime(String time) {
+            this.time = time;
+        }
+
+        public String getTimezone() {
+            return timezone;
+        }
+
+        public void setTimezone(String timezone) {
+            this.timezone = timezone;
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/DefaultUnitTest.java

@@ -0,0 +1,68 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.time.Instant;
+
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.Test;
+
+public class DefaultUnitTest {
+
+    @Test
+    public void whenDeserializing_thenFieldsGetDefaultValues() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+    public static class Post {
+        private String title;
+        private String author;
+        private String posted;
+
+        public Post() {
+            posted = Instant.now().toString();
+        }
+
+        public Post(String title, String author, String posted) {
+            this.title = title;
+            this.author = author;
+            this.posted = posted;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        public String getPosted() {
+            return posted;
+        }
+
+        public void setPosted(String posted) {
+            this.posted = posted;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).append("posted", posted)
+                .toString();
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/PrimitiveUnitTest.java

@@ -0,0 +1,77 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.Test;
+
+public class PrimitiveUnitTest {
+    @Test
+    public void whenSerializing_thenCorrectJsonProduced() {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        Post post = new Post("My Post", "Baeldung", "This is my post");
+        String json = jsonAdapter.toJson(post);
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenCorrectJsonConsumed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"author\":\"Baeldung\",\"text\":\"This is my post\",\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+
+    public static class Post {
+        private String title;
+        private String author;
+        private String text;
+
+        public Post() {
+        }
+
+        public Post(String title, String author, String text) {
+            this.title = title;
+            this.author = author;
+            this.text = text;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        public String getText() {
+            return text;
+        }
+
+        public void setText(String text) {
+            this.text = text;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).append("text", text)
+                .toString();
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/RenameUnitTest.java

@@ -0,0 +1,68 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+
+import com.squareup.moshi.Json;
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.jupiter.api.Test;
+
+public class RenameUnitTest {
+
+    @Test
+    public void whenSerializing_thenFieldsGetRenamed() {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        Post post = new Post("My Post", "Baeldung");
+        String json = jsonAdapter.toJson(post);
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenSerializing_thenRenamedFieldsGetConsumed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"authored_by\":\"Baeldung\",\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+    public static class Post {
+        private String title;
+        @Json(name = "authored_by")
+        private String author;
+
+        public Post() {
+        }
+
+        public Post(String title, String author) {
+            this.title = title;
+            this.author = author;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).toString();
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/SimpleAdapterUnitTest.java

@@ -0,0 +1,129 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import com.squareup.moshi.FromJson;
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import com.squareup.moshi.ToJson;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.Test;
+
+public class SimpleAdapterUnitTest {
+    @Test
+    public void whenSerializing_thenAdapterUsed() {
+        Moshi moshi = new Moshi.Builder()
+          .add(new AuthorAdapter())
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        Post post = new Post("My Post", new Author("Baeldung", "baeldung@example.com"), "This is my post");
+        String json = jsonAdapter.toJson(post);
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenAdapterUsed() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .add(new AuthorAdapter())
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"author\":\"Baeldung <baeldung@example.com>\",\"text\":\"This is my post\",\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+    public static class AuthorAdapter {
+        private Pattern pattern = Pattern.compile("^(.*) <(.*)>$");
+        @ToJson
+        public String toJson(Author author) {
+            return author.name + " <" + author.email + ">";
+        }
+
+        @FromJson
+        public Author fromJson(String author) {
+            Matcher matcher = pattern.matcher(author);
+            return matcher.find() ? new Author(matcher.group(1), matcher.group(2)) : null;
+        }
+    }
+
+    public static class Author {
+        private String name;
+        private String email;
+
+        public Author() {
+        }
+
+        public Author(String name, String email) {
+            this.name = name;
+            this.email = email;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public void setName(String name) {
+            this.name = name;
+        }
+
+        public String getEmail() {
+            return email;
+        }
+
+        public void setEmail(String email) {
+            this.email = email;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("name", name).append("email", email).toString();
+        }
+    }
+    public static class Post {
+        private String title;
+        private Author author;
+        private String text;
+
+        public Post() {
+        }
+
+        public Post(String title, Author author, String text) {
+            this.title = title;
+            this.author = author;
+            this.text = text;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public Author getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(Author author) {
+            this.author = author;
+        }
+
+        public String getText() {
+            return text;
+        }
+
+        public void setText(String text) {
+            this.text = text;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).append("text", text)
+              .toString();
+        }
+    }
+}

libraries-3/src/test/java/com/baeldung/moshi/TransientUnitTest.java

@@ -0,0 +1,66 @@
+package com.baeldung.moshi;
+
+import java.io.IOException;
+
+import com.squareup.moshi.JsonAdapter;
+import com.squareup.moshi.Moshi;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+import org.junit.jupiter.api.Test;
+
+public class TransientUnitTest {
+
+    @Test
+    public void whenSerializing_thenTransientFieldIgnored() {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        Post post = new Post("My Post", "Baeldung");
+        String json = jsonAdapter.toJson(post);
+        System.out.println(json);
+    }
+
+    @Test
+    public void whenDeserializing_thenTransientFieldIgnored() throws IOException {
+        Moshi moshi = new Moshi.Builder()
+          .build();
+        JsonAdapter<Post> jsonAdapter = moshi.adapter(Post.class);
+
+        String json = "{\"authored_by\":\"Baeldung\",\"title\":\"My Post\"}";
+        Post post = jsonAdapter.fromJson(json);
+        System.out.println(post);
+    }
+    public static class Post {
+        private String title;
+        private transient String author;
+
+        public Post() {
+        }
+
+        public Post(String title, String author) {
+            this.title = title;
+            this.author = author;
+        }
+
+        public String getTitle() {
+            return title;
+        }
+
+        public void setTitle(String title) {
+            this.title = title;
+        }
+
+        public String getAuthor() {
+            return author;
+        }
+
+        public void setAuthor(String author) {
+            this.author = author;
+        }
+
+        @Override
+        public String toString() {
+            return new ToStringBuilder(this).append("title", title).append("author", author).toString();
+        }
+    }
+}

lombok-custom/pom.xml

@@ -36,12 +36,12 @@
 
     <profiles>
         <profile>
-            <id>default-tools.jar</id>
+            <id>default-profile</id>
             <activation>
-                <property>
+                <activeByDefault>true</activeByDefault>
-                    <name>java.vendor</name>
+                <file>
-                    <value>Oracle Corporation</value>
+                    <exists>${java.home}/../lib/tools.jar</exists>
-                </property>
+                </file>
             </activation>
             <dependencies>
                 <dependency>
@@ -53,6 +53,24 @@
                 </dependency>
             </dependencies>
         </profile>
+        <profile>
+            <id>mac-profile</id>
+            <activation>
+                <activeByDefault>false</activeByDefault>
+                <file>
+                    <exists>${java.home}/../Classes/classes.jar</exists>
+                </file>
+            </activation>
+            <dependencies>
+                <dependency>
+                    <groupId>com.sun</groupId>
+                    <artifactId>tools</artifactId>
+                    <version>${java.version}</version>
+                    <scope>system</scope>
+                    <systemPath>${java.home}/../Classes/classes.jar</systemPath>
+                </dependency>
+            </dependencies>
+        </profile>
     </profiles>
 
     <properties>

persistence-modules/spring-data-jpa-4/pom.xml

@@ -23,6 +23,16 @@
             <artifactId>spring-boot-starter-data-jpa</artifactId>
         </dependency>
 
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jdbc</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>mysql</groupId>
+            <artifactId>mysql-connector-java</artifactId>
+        </dependency>
+
         <dependency>
             <groupId>com.h2database</groupId>
             <artifactId>h2</artifactId>

persistence-modules/spring-data-jpa-4/src/main/java/com/baeldung/storedprocedure/StoredProcedureApplication.java

@@ -1,14 +1,13 @@
-package hello;
+package com.baeldung.storedprocedure;
 
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
-import org.springframework.scheduling.annotation.EnableScheduling;
 
 @SpringBootApplication
-@EnableScheduling
+public class StoredProcedureApplication {
-public class Application {
 
     public static void main(String[] args) {
-        SpringApplication.run(Application.class);
+        SpringApplication.run(StoredProcedureApplication.class, args);
     }
+
 }

persistence-modules/spring-data-jpa-4/src/main/java/com/baeldung/storedprocedure/controller/CarController.java

@@ -0,0 +1,47 @@
+package com.baeldung.storedprocedure.controller;
+
+import java.util.List;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.baeldung.storedprocedure.entity.Car;
+import com.baeldung.storedprocedure.service.CarService;
+
+@RestController
+public class CarController {
+    @Autowired
+    private CarService carService;
+
+    @GetMapping(path = "/modelcount")
+    public long getTotalCarsByModel(@RequestParam("model") String model) {
+        return carService.getTotalCarsByModel(model);
+    }
+
+    @GetMapping(path = "/modelcountP")
+    public long getTotalCarsByModelProcedureName(@RequestParam("model") String model) {
+        return carService.getTotalCarsByModelProcedureName(model);
+    }
+    
+    @GetMapping(path = "/modelcountV")
+    public long getTotalCarsByModelVaue(@RequestParam("model") String model) {
+        return carService.getTotalCarsByModelValue(model);
+    }
+    
+    @GetMapping(path = "/modelcountEx")
+    public long getTotalCarsByModelExplicit(@RequestParam("model") String model) {
+        return carService.getTotalCarsByModelExplicit(model);
+    }
+    
+    @GetMapping(path = "/modelcountEn")
+    public long getTotalCarsByModelEntity(@RequestParam("model") String model) {
+        return carService.getTotalCarsByModelEntity(model);
+    }
+    
+    @GetMapping(path = "/carsafteryear")
+    public List<Car> findCarsAfterYear(@RequestParam("year") Integer year) {
+        return carService.findCarsAfterYear(year);
+    }
+}

persistence-modules/spring-data-jpa-4/src/main/java/com/baeldung/storedprocedure/entity/Car.java

@@ -0,0 +1,41 @@
+package com.baeldung.storedprocedure.entity;
+
+import javax.persistence.Column;
+import javax.persistence.Entity;
+import javax.persistence.GeneratedValue;
+import javax.persistence.GenerationType;
+import javax.persistence.Id;
+import javax.persistence.NamedStoredProcedureQuery;
+import javax.persistence.StoredProcedureParameter;
+import javax.persistence.ParameterMode;
+
+@Entity
+@NamedStoredProcedureQuery(name = "Car.getTotalCardsbyModelEntity", procedureName = "GET_TOTAL_CARS_BY_MODEL", parameters = {
+    @StoredProcedureParameter(mode = ParameterMode.IN, name = "model_in", type = String.class),
+    @StoredProcedureParameter(mode = ParameterMode.OUT, name = "count_out", type = Integer.class) })
+
+public class Car {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column
+    private long id;
+
+    @Column
+    private String model;
+
+    @Column
+    private Integer year;
+
+    public long getId() {
+        return id;
+    }
+
+    public String getModel() {
+        return model;
+    }
+
+    public Integer getYear() {
+        return year;
+    }
+
+}

persistence-modules/spring-data-jpa-4/src/main/java/com/baeldung/storedprocedure/repository/CarRepository.java

@@ -0,0 +1,34 @@
+package com.baeldung.storedprocedure.repository;
+
+import java.util.List;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Query;
+import org.springframework.data.jpa.repository.query.Procedure;
+import org.springframework.data.repository.query.Param;
+import org.springframework.stereotype.Repository;
+
+import com.baeldung.storedprocedure.entity.Car;
+
+@Repository
+public interface CarRepository extends JpaRepository<Car, Integer> {
+
+    @Procedure
+    int GET_TOTAL_CARS_BY_MODEL(String model);
+    
+    @Procedure("GET_TOTAL_CARS_BY_MODEL")
+    int getTotalCarsByModel(String model);
+    
+    @Procedure(procedureName = "GET_TOTAL_CARS_BY_MODEL")
+    int getTotalCarsByModelProcedureName(String model);
+    
+    @Procedure(value = "GET_TOTAL_CARS_BY_MODEL")
+    int getTotalCarsByModelValue(String model);
+
+    @Procedure(name = "Car.getTotalCardsbyModelEntity")
+    int getTotalCarsByModelEntiy(@Param("model_in") String model);
+        
+    @Query(value = "CALL FIND_CARS_AFTER_YEAR(:year_in);", nativeQuery = true)
+    List<Car> findCarsAfterYear(@Param("year_in") Integer year_in);
+
+}

persistence-modules/spring-data-jpa-4/src/main/java/com/baeldung/storedprocedure/service/CarService.java

@@ -0,0 +1,39 @@
+package com.baeldung.storedprocedure.service;
+
+import java.util.List;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import com.baeldung.storedprocedure.entity.Car;
+import com.baeldung.storedprocedure.repository.CarRepository;
+
+@Service
+public class CarService {
+    @Autowired
+    private CarRepository carRepository;
+
+    public int getTotalCarsByModel(String model) {
+        return carRepository.getTotalCarsByModel(model);
+    }
+    
+    public int getTotalCarsByModelProcedureName(String model) {
+        return carRepository.getTotalCarsByModelProcedureName(model);
+    }
+    
+    public int getTotalCarsByModelValue(String model) {
+        return carRepository.getTotalCarsByModelValue(model);
+    }
+    
+    public int getTotalCarsByModelExplicit(String model) {
+        return carRepository.GET_TOTAL_CARS_BY_MODEL(model);
+    }
+    
+    public int getTotalCarsByModelEntity(String model) {
+        return carRepository.getTotalCarsByModelEntiy(model);
+    }
+
+    public List<Car> findCarsAfterYear(Integer year) {
+        return carRepository.findCarsAfterYear(year);
+    }
+}

persistence-modules/spring-data-jpa-4/src/main/resources/application.properties

@@ -1 +1,5 @@
 spring.jpa.show-sql=true
+#MySql
+spring.datasource.url=jdbc:mysql://localhost:3306/baeldung
+spring.datasource.username=baeldung
+spring.datasource.password=baeldung

persistence-modules/spring-data-jpa-4/src/main/resources/car-mysql.sql

@@ -0,0 +1,27 @@
+DROP TABLE IF EXISTS car;
+
+CREATE TABLE car (id int(10) NOT NULL AUTO_INCREMENT, 
+    model varchar(50) NOT NULL, 
+    year int(4) NOT NULL, 
+    PRIMARY KEY (id));
+ 
+INSERT INTO car (model, year) VALUES ('BMW', 2000);
+INSERT INTO car (model, year) VALUES ('BENZ', 2010);
+INSERT INTO car (model, year) VALUES ('PORCHE', 2005);
+INSERT INTO car (model, year) VALUES ('PORCHE', 2004);
+
+DELIMITER $$
+
+DROP PROCEDURE IF EXISTS FIND_CARS_AFTER_YEAR$$
+CREATE PROCEDURE FIND_CARS_AFTER_YEAR(IN year_in INT)
+BEGIN 
+    SELECT * FROM car WHERE year >= year_in ORDER BY year;
+END$$
+
+DROP PROCEDURE IF EXISTS GET_TOTAL_CARS_BY_MODEL$$
+CREATE PROCEDURE GET_TOTAL_CARS_BY_MODEL(IN model_in VARCHAR(50), OUT count_out INT)
+BEGIN 
+    SELECT COUNT(*) into count_out from car WHERE model = model_in;
+END$$
+
+DELIMITER ;

play-framework/async-http/.g8/form/app/controllers/$model__Camel$Controller.java

@@ -0,0 +1,43 @@
+package controllers;
+
+import play.data.Form;
+import play.data.FormFactory;
+import play.mvc.Controller;
+import play.mvc.Result;
+
+import javax.inject.Inject;
+
+// Add the following to conf/routes 
+/*
+GET     /$model;format="camel"$        controllers.$model;format="Camel"$Controller.$model;format="camel"$Get
+POST    /$model;format="camel"$        controllers.$model;format="Camel"$Controller.$model;format="camel"$Post
+*/
+
+/**
+ * $model;format="Camel"$ form controller for Play Java
+ */
+public class $model;format="Camel"$Controller extends Controller {
+
+    private final Form<$model;format="Camel"$Data> $model;format="camel"$Form;
+
+    @Inject
+    public $model;format="Camel"$Controller(FormFactory formFactory) {
+        this.$model;format="camel"$Form = formFactory.form($model;format="Camel"$Data.class);
+    }
+
+    public Result $model;format="camel"$Get() {
+        return ok(views.html.$model;format="camel"$.form.render($model;format="camel"$Form));
+    }
+
+    public Result $model;format="camel"$Post() {
+        Form<$model;format="Camel"$Data> boundForm = $model;format="camel"$Form.bindFromRequest();
+        if (boundForm.hasErrors()) {
+            return badRequest(views.html.$model;format="camel"$.form.render(boundForm));
+        } else {
+            $model;format="Camel"$Data $model;format="camel"$ = boundForm.get();
+            flash("success", "$model;format="Camel"$ " + $model;format="camel"$);
+            return redirect(routes.$model;format="Camel"$Controller.$model;format="camel"$Get());
+        }
+    }
+
+}

play-framework/async-http/.g8/form/app/controllers/$model__Camel$Data.java

@@ -0,0 +1,37 @@
+package controllers;
+
+import play.data.validation.Constraints;
+
+public class $model;format="Camel"$Data {
+
+    @Constraints.Required
+    private String name;
+
+    @Constraints.Required
+    private Integer age;
+
+    public $model;format="Camel"$Data() {
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public Integer getAge() {
+        return age;
+    }
+
+    public void setAge(Integer age) {
+        this.age = age;
+    }
+
+    @Override
+    public String toString() {
+        return String.format("$model;format="Camel"$Data(%s, %s)", name, age);
+    }
+
+}

play-framework/async-http/.g8/form/app/views/$model__camel$/form.scala.html

@@ -0,0 +1,12 @@
+@($model;format="camel"$Form: Form[$model;format="Camel"$Data])
+
+<h1>$model;format="camel"$ form</h1>
+
+@flash.getOrDefault("success", "")
+
+@helper.form(action = routes.$model;format="Camel"$Controller.$model;format="camel"$Post()) {
+  @helper.CSRF.formField
+  @helper.inputText($model;format="camel"$Form("name"))
+  @helper.inputText($model;format="camel"$Form("age"))
+  <input type="submit" value="submit"/>
+}

play-framework/async-http/.g8/form/default.properties

@@ -0,0 +1,2 @@
+description = Generates a Controller with form handling
+model = user

play-framework/async-http/.g8/form/generated-test/README.md

@@ -0,0 +1 @@
+Temporary file until g8-scaffold will generate "test" directory

play-framework/async-http/.g8/form/generated-test/controllers/$model__Camel$ControllerTest.java

@@ -0,0 +1,50 @@
+package controllers;
+
+import org.junit.Test;
+import play.Application;
+import play.filters.csrf.*;
+import play.inject.guice.GuiceApplicationBuilder;
+import play.mvc.*;
+import play.test.WithApplication;
+
+import java.util.HashMap;
+
+import static org.junit.Assert.assertEquals;
+import static play.mvc.Http.RequestBuilder;
+import static play.mvc.Http.Status.OK;
+import static play.test.Helpers.*;
+import static play.api.test.CSRFTokenHelper.*;
+
+public class $model;format="Camel"$ControllerTest extends WithApplication {
+
+    @Override
+    protected Application provideApplication() {
+        return new GuiceApplicationBuilder().build();
+    }
+
+    @Test
+    public void test$model;format="Camel"$Get() {
+        RequestBuilder request = new RequestBuilder()
+                .method(GET)
+                .uri("/$model;format="camel"$");
+
+        Result result = route(app, request);
+        assertEquals(OK, result.status());
+    }
+
+    @Test
+    public void test$model;format="Camel"$Post() {
+        HashMap<String, String> formData = new HashMap<>();
+        formData.put("name", "play");
+        formData.put("age", "4");
+        RequestBuilder request = addCSRFToken(new RequestBuilder()
+                .header(Http.HeaderNames.HOST, "localhost")
+                .method(POST)
+                .bodyForm(formData)
+                .uri("/$model;format="camel"$"));
+
+        Result result = route(app, request);
+        assertEquals(SEE_OTHER, result.status());
+    }
+
+}

play-framework/async-http/.gitignore

@@ -0,0 +1,8 @@
+logs
+target
+/.idea
+/.idea_modules
+/.classpath
+/.project
+/.settings
+/RUNNING_PID

play-framework/async-http/app/controllers/HomeController.java

@@ -0,0 +1,38 @@
+package controllers;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.common.collect.ImmutableMap;
+import java.util.Collections;
+import java.util.Map;
+import play.mvc.Controller;
+import play.mvc.Http;
+import play.mvc.Result;
+
+/**
+ * This controller contains an action to handle HTTP requests to the application's home page.
+ */
+public class HomeController extends Controller {
+
+    /**
+     * An action that renders an HTML page with a welcome message. The configuration in the
+     * <code>routes</code> file means that this method will be called when the application receives
+     * a
+     * <code>GET</code> request with a path of <code>/</code>.
+     */
+    public Result index(Http.Request request) throws JsonProcessingException {
+        return ok(printStats(request));
+    }
+
+    private String printStats(Http.Request request) throws JsonProcessingException {
+        Map<String, String[]> stringMap = request.body()
+                                                 .asFormUrlEncoded();
+        Map<String, Object> map = ImmutableMap.of(
+          "Result", "ok",
+          "GetParams", request.queryString(),
+          "PostParams", stringMap == null ? Collections.emptyMap() : stringMap,
+          "Headers", request.getHeaders().toMap()
+        );
+        return new ObjectMapper().writerWithDefaultPrettyPrinter().writeValueAsString(map);
+    }
+}

play-framework/async-http/app/views/index.scala.html

@@ -0,0 +1,5 @@
+@()
+
+@main("Welcome to Play") {
+  <h1>Welcome to Play!</h1>
+}

play-framework/async-http/app/views/main.scala.html

@@ -0,0 +1,24 @@
+@*
+ * This template is called from the `index` template. This template
+ * handles the rendering of the page header and body tags. It takes
+ * two arguments, a `String` for the title of the page and an `Html`
+ * object to insert into the body of the page.
+ *@
+@(title: String)(content: Html)
+
+<!DOCTYPE html>
+<html lang="en">
+    <head>
+        @* Here's where we render the page title `String`. *@
+        <title>@title</title>
+        <link rel="stylesheet" media="screen" href="@routes.Assets.versioned("stylesheets/main.css")">
+        <link rel="shortcut icon" type="image/png" href="@routes.Assets.versioned("images/favicon.png")">
+    </head>
+    <body>
+        @* And here's where we render the `Html` object containing
+         * the page content. *@
+        @content
+
+        <script src="@routes.Assets.versioned("javascripts/main.js")" type="text/javascript"></script>
+    </body>
+</html>

play-framework/async-http/build.sbt

@@ -0,0 +1,12 @@
+name := """async"""
+organization := "com.example"
+
+version := "1.0-SNAPSHOT"
+
+lazy val root = (project in file(".")).enablePlugins(PlayJava)
+
+scalaVersion := "2.13.1"
+
+// comment out the original line
+libraryDependencies += guice
+libraryDependencies += javaWs

play-framework/async-http/conf/application.conf

@@ -0,0 +1,11 @@
+# This is the main configuration file for the application.
+# https://www.playframework.com/documentation/latest/ConfigFile
+play.ws.followRedirects=false
+play.ws.useragent=MyPlayApplication
+play.ws.compressionEnabled=true
+# time to wait for the connection to be established
+play.ws.timeout.connection=30.seconds
+# time to wait for data after the connection is open
+play.ws.timeout.idle=30.seconds
+# max time available to complete the request
+play.ws.timeout.request=300.seconds

play-framework/async-http/conf/logback.xml

@@ -0,0 +1,36 @@
+<!-- https://www.playframework.com/documentation/latest/SettingsLogger -->
+<configuration>
+
+  <conversionRule conversionWord="coloredLevel" converterClass="play.api.libs.logback.ColoredLevel" />
+
+  <appender name="FILE" class="ch.qos.logback.core.FileAppender">
+    <file>${application.home:-.}/logs/application.log</file>
+    <encoder>
+      <pattern>%date [%level] from %logger in %thread - %message%n%xException</pattern>
+    </encoder>
+  </appender>
+
+  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+    <encoder>
+      <pattern>%coloredLevel %logger{15} - %message%n%xException{10}</pattern>
+    </encoder>
+  </appender>
+
+  <appender name="ASYNCFILE" class="ch.qos.logback.classic.AsyncAppender">
+    <appender-ref ref="FILE" />
+  </appender>
+
+  <appender name="ASYNCSTDOUT" class="ch.qos.logback.classic.AsyncAppender">
+    <appender-ref ref="STDOUT" />
+  </appender>
+
+  <logger name="play" level="INFO" />
+  <logger name="application" level="DEBUG" />
+  <logger name="controllers" level="DEBUG" />
+
+  <root level="WARN">
+    <appender-ref ref="ASYNCFILE" />
+    <appender-ref ref="ASYNCSTDOUT" />
+  </root>
+
+</configuration>

play-framework/async-http/conf/routes

@@ -0,0 +1,10 @@
+# Routes
+# This file defines all application routes (Higher priority routes first)
+# ~~~~
+
+# An example controller showing a sample home page
+GET     /                           controllers.HomeController.index(request: Request)
+POST     /                           controllers.HomeController.index(request: Request)
+
+# Map static resources from the /public folder to the /assets URL path
+GET     /assets/*file               controllers.Assets.versioned(path="/public", file: Asset)

play-framework/async-http/project/build.properties

@@ -0,0 +1 @@
+sbt.version=1.3.3

play-framework/async-http/project/plugins.sbt

@@ -0,0 +1,7 @@
+// The Play plugin
+addSbtPlugin("com.typesafe.play" % "sbt-plugin" % "2.7.3")
+
+// Defines scaffolding (found under .g8 folder)
+// http://www.foundweekends.org/giter8/scaffolding.html
+// sbt "g8Scaffold form"
+addSbtPlugin("org.foundweekends.giter8" % "sbt-giter8-scaffold" % "0.11.0")