Merge pull request #3389 from k0l0ssus/master

Java-Vavr Stream Comparison Sample

java-vavr-stream/pom.xml

@@ -0,0 +1,20 @@
+<?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.samples</groupId>
+    <artifactId>java-vavr-stream</artifactId>
+    <version>1.0</version>
+    <packaging>jar</packaging>
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+        <maven.compiler.source>1.8</maven.compiler.source>
+        <maven.compiler.target>1.8</maven.compiler.target>
+    </properties>
+    <dependencies>
+        <dependency>
+            <groupId>io.vavr</groupId>
+            <artifactId>vavr</artifactId>
+            <version>0.9.2</version>
+        </dependency>
+    </dependencies>
+</project>

java-vavr-stream/src/main/java/com/baeldung/samples/java/vavr/VavrSampler.java

@@ -0,0 +1,98 @@
+package com.baeldung.samples.java.vavr;
+
+import io.vavr.collection.Stream;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.IntStream;
+
+/**
+ *
+ * @author baeldung
+ */
+public class VavrSampler {
+
+    static int[] intArray = new int[]{1, 2, 4};
+    static List<Integer> intList = new ArrayList<Integer>();
+    static int[][] intOfInts = new int[][]{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
+
+    public static void main(String[] args) {
+        vavrStreamElementAccess();
+        System.out.println("====================================");
+        vavrParallelStreamAccess();
+        System.out.println("====================================");
+        jdkFlatMapping();
+        System.out.println("====================================");
+        vavrStreamManipulation();
+        System.out.println("====================================");
+        vavrStreamDistinct();
+    }
+
+    public static void vavrStreamElementAccess() {
+        System.out.println("Vavr Element Access");
+        System.out.println("====================================");
+        Stream<Integer> vavredStream = Stream.ofAll(intArray);
+        System.out.println("Vavr index access: " + vavredStream.get(2));
+        System.out.println("Vavr head element access: " + vavredStream.get());
+
+        Stream<String> vavredStringStream = Stream.of("foo", "bar", "baz");
+        System.out.println("Find foo " + vavredStringStream.indexOf("foo"));
+    }
+
+    public static void vavrParallelStreamAccess() {
+        try {
+            System.out.println("Vavr Stream Concurrent Modification");
+            System.out.println("====================================");
+            Stream<Integer> vavrStream = Stream.ofAll(intList);
+            intList.add(5);
+            vavrStream.forEach(i -> System.out.println("in a Vavr Stream: " + i));
+        } catch (Exception ex) {
+            ex.printStackTrace();
+        }
+        
+        Stream<Integer> wrapped = Stream.ofAll(intArray);
+        intArray[2] = 5;
+        wrapped.forEach(i -> System.out.println("Vavr looped " + i));
+    }
+
+    public static void jdkFlatMapping() {
+        System.out.println("JDK FlatMap -> Uncomment line 68 to test");
+        System.out.println("====================================");
+        int[][] intOfInts = new int[][]{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
+
+        IntStream mapToInt = Arrays.stream(intOfInts)
+                .map(intArr -> Arrays.stream(intArr))
+                .flatMapToInt(val -> val.map(n -> {
+            return n * n;
+        }))
+                .peek(n -> System.out.println("Peeking at " + n));
+        //Uncomment to execute pipeline
+        //mapToInt.forEach(n -> System.out.println("FlatMapped Result "+n));
+    }
+
+    public static void vavrStreamManipulation() {
+        System.out.println("Vavr Stream Manipulation");
+        System.out.println("====================================");
+        List<String> stringList = new ArrayList<>();
+        stringList.add("foo");
+        stringList.add("bar");
+        stringList.add("baz");
+        Stream<String> vavredStream = Stream.ofAll(stringList);
+        vavredStream.forEach(item -> System.out.println("Vavr Stream item: " + item));
+        Stream<String> vavredStream2 = vavredStream.insert(2, "buzz");
+        vavredStream2.forEach(item -> System.out.println("Vavr Stream item after stream addition: " + item));
+        stringList.forEach(item -> System.out.println("List item after stream addition: " + item));
+        Stream<String> deletionStream = vavredStream.remove("bar");
+        deletionStream.forEach(item -> System.out.println("Vavr Stream item after stream item deletion: " + item));
+
+    }
+
+    public static void vavrStreamDistinct() {
+        Stream<String> vavredStream = Stream.of("foo", "bar", "baz", "buxx", "bar", "bar", "foo");
+        Stream<String> distinctVavrStream = vavredStream.distinctBy((y, z) -> {
+            return y.compareTo(z);
+        });
+        distinctVavrStream.forEach(item -> System.out.println("Vavr Stream item after distinct query " + item));
+
+    }
+}

pom.xml

@@ -87,6 +87,7 @@
         <!--         <module>persistence-modules/java-cassandra</module> -->
         <module>vavr</module>
 		<module>java-lite</module>
+	<module>java-vavr-stream</module>
         <module>javax-servlets</module>
         <module>javaxval</module>
         <module>jaxb</module>