Merge branch 'master' of https://github.com/eugenp/tutorials into task/BAEL-8142

This commit is contained in:
Dhawal Kapil 2018-08-26 01:11:06 +05:30
commit cd1367756e
47 changed files with 568 additions and 30 deletions

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@ -87,7 +87,7 @@ public class State {
void randomPlay() {
List<Position> availablePositions = this.board.getEmptyPositions();
int totalPossibilities = availablePositions.size();
int selectRandom = (int) (Math.random() * ((totalPossibilities - 1) + 1));
int selectRandom = (int) (Math.random() * totalPossibilities);
this.board.performMove(this.playerNo, availablePositions.get(selectRandom));
}

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@ -65,7 +65,7 @@ public class Node {
public Node getRandomChildNode() {
int noOfPossibleMoves = this.childArray.size();
int selectRandom = (int) (Math.random() * ((noOfPossibleMoves - 1) + 1));
int selectRandom = (int) (Math.random() * noOfPossibleMoves);
return this.childArray.get(selectRandom);
}

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@ -0,0 +1,35 @@
package com.baeldung.algorithms.string;
public class EnglishAlphabetLetters {
public static boolean checkStringForAllTheLetters(String input) {
boolean[] visited = new boolean[26];
int index = 0;
for (int id = 0; id < input.length(); id++) {
if ('a' <= input.charAt(id) && input.charAt(id) <= 'z') {
index = input.charAt(id) - 'a';
} else if ('A' <= input.charAt(id) && input.charAt(id) <= 'Z') {
index = input.charAt(id) - 'A';
}
visited[index] = true;
}
for (int id = 0; id < 26; id++) {
if (!visited[id]) {
return false;
}
}
return true;
}
public static boolean checkStringForAllLetterUsingStream(String input) {
long c = input.toLowerCase().chars().filter(ch -> ch >= 'a' && ch <= 'z').distinct().count();
return c == 26;
}
public static void main(String[] args) {
checkStringForAllLetterUsingStream("intit");
}
}

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@ -1,4 +1,4 @@
package algorithms;
package com.baeldung.algorithms;
import org.junit.Assert;
import org.junit.Test;

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@ -1,4 +1,4 @@
package algorithms;
package com.baeldung.algorithms;
import org.junit.Assert;
import org.junit.Test;

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@ -1,4 +1,4 @@
package algorithms;
package com.baeldung.algorithms;
import com.baeldung.algorithms.hillclimbing.HillClimbing;
import com.baeldung.algorithms.hillclimbing.State;

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@ -1,4 +1,4 @@
package algorithms;
package com.baeldung.algorithms;
import com.baeldung.algorithms.middleelementlookup.MiddleElementLookup;
import com.baeldung.algorithms.middleelementlookup.Node;

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@ -1,4 +1,4 @@
package algorithms;
package com.baeldung.algorithms;
import com.baeldung.algorithms.automata.*;
import org.junit.Test;

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@ -1,4 +1,4 @@
package algorithms;
package com.baeldung.algorithms;
import org.junit.Assert;
import org.junit.Test;

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@ -1,4 +1,4 @@
package algorithms;
package com.baeldung.algorithms;
import org.junit.Assert;

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@ -1,4 +1,4 @@
package algorithms.binarysearch;
package com.baeldung.algorithms.binarysearch;
import java.util.Arrays;
import java.util.List;

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@ -1,4 +1,4 @@
package algorithms.mcts;
package com.baeldung.algorithms.mcts;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

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@ -1,4 +1,4 @@
package algorithms.minimax;
package com.baeldung.algorithms.minimax;
import org.junit.Before;
import org.junit.Test;

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@ -0,0 +1,20 @@
package com.baeldung.algorithms.string;
import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
public class EnglishAlphabetLettersUnitTest {
@Test
void givenString_whenContainsAllCharacter_thenTrue() {
String input = "Farmer jack realized that big yellow quilts were expensive";
Assertions.assertTrue(EnglishAlphabetLetters.checkStringForAllTheLetters(input));
}
@Test
void givenString_whenContainsAllCharacter_thenUsingStreamExpectTrue() {
String input = "Farmer jack realized that big yellow quilts were expensive";
Assertions.assertTrue(EnglishAlphabetLetters.checkStringForAllLetterUsingStream(input));
}
}

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@ -9,15 +9,10 @@
- [Java 8 New Features](http://www.baeldung.com/java-8-new-features)
- [Lambda Expressions and Functional Interfaces: Tips and Best Practices](http://www.baeldung.com/java-8-lambda-expressions-tips)
- [The Double Colon Operator in Java 8](http://www.baeldung.com/java-8-double-colon-operator)
- [Java 8 Streams Advanced](http://www.baeldung.com/java-8-streams)
- [Introduction to Java 8 Streams](http://www.baeldung.com/java-8-streams-introduction)
- [Guide to Java 8 groupingBy Collector](http://www.baeldung.com/java-groupingby-collector)
- [Strategy Design Pattern in Java 8](http://www.baeldung.com/java-strategy-pattern)
- [Java 8 and Infinite Streams](http://www.baeldung.com/java-inifinite-streams)
- [Exceptions in Java 8 Lambda Expressions](http://www.baeldung.com/java-lambda-exceptions)
- [Java 8 Stream findFirst() vs. findAny()](http://www.baeldung.com/java-stream-findfirst-vs-findany)
- [Guide to Java 8 Comparator.comparing()](http://www.baeldung.com/java-8-comparator-comparing)
- [How to Get the Last Element of a Stream in Java?](http://www.baeldung.com/java-stream-last-element)
- [Introduction to the Java 8 Date/Time API](http://www.baeldung.com/java-8-date-time-intro)
- [Migrating to the New Java 8 Date Time API](http://www.baeldung.com/migrating-to-java-8-date-time-api)
- [Guide To Java 8 Optional](http://www.baeldung.com/java-optional)
@ -27,15 +22,10 @@
- [Finding Max/Min of a List or Collection](http://www.baeldung.com/java-collection-min-max)
- [Java Base64 Encoding and Decoding](http://www.baeldung.com/java-base64-encode-and-decode)
- [The Difference Between map() and flatMap()](http://www.baeldung.com/java-difference-map-and-flatmap)
- [Merging Streams in Java](http://www.baeldung.com/java-merge-streams)
- [“Stream has already been operated upon or closed” Exception in Java](http://www.baeldung.com/java-stream-operated-upon-or-closed-exception)
- [Display All Time Zones With GMT And UTC in Java](http://www.baeldung.com/java-time-zones)
- [Copy a File with Java](http://www.baeldung.com/java-copy-file)
- [Static and Default Methods in Interfaces in Java](http://www.baeldung.com/java-static-default-methods)
- [Iterable to Stream in Java](http://www.baeldung.com/java-iterable-to-stream)
- [How to Iterate Over a Stream With Indices](http://www.baeldung.com/java-stream-indices)
- [Efficient Word Frequency Calculator in Java](http://www.baeldung.com/java-word-frequency)
- [Primitive Type Streams in Java 8](http://www.baeldung.com/java-8-primitive-streams)
- [Fail-Safe Iterator vs Fail-Fast Iterator](http://www.baeldung.com/java-fail-safe-vs-fail-fast-iterator)
- [Shuffling Collections In Java](http://www.baeldung.com/java-shuffle-collection)
- [Introduction to Spliterator in Java](http://www.baeldung.com/java-spliterator)

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@ -89,11 +89,6 @@
<artifactId>vavr</artifactId>
<version>${vavr.version}</version>
</dependency>
<dependency>
<groupId>one.util</groupId>
<artifactId>streamex</artifactId>
<version>${streamex.version}</version>
</dependency>
<dependency>
<groupId>joda-time</groupId>
<artifactId>joda-time</artifactId>
@ -177,7 +172,6 @@
<lombok.version>1.16.12</lombok.version>
<vavr.version>0.9.0</vavr.version>
<protonpack.version>1.13</protonpack.version>
<streamex.version>0.6.5</streamex.version>
<joda.version>2.10</joda.version>
<!-- testing -->
<assertj.version>3.6.1</assertj.version>

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@ -0,0 +1,21 @@
package com.baeldung.classcastexception;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class ClassCastException {
public static void main(String[] args) {
String p1 = new String("John");
String p2 = new String("Snow");
String[] strArray = new String[] { p1, p2 };
ArrayList<String> strList = (ArrayList<String>) Arrays.asList(strArray);
// To fix the ClassCastException at above line, modify the code as:
// List<String> strList = Arrays.asList(strArray);
System.out.println("String list: " + strList);
}
}

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@ -8,7 +8,7 @@ public class PersonRepository {
@Nullable
public String findNameById(String id) {
return id == null ? null : "example-name";
return id == null ? null : "Name";
}
public List<String> findAll() throws SQLException {

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@ -4,6 +4,7 @@ import org.junit.Test;
import java.util.Optional;
import static org.junit.Assert.assertEquals;
import static org.junit.jupiter.api.Assertions.assertAll;
import static org.junit.jupiter.api.Assertions.assertThrows;
@ -29,4 +30,14 @@ public class PersonRepositoryUnitTest {
.orElseThrow(Exception::new));
}
@Test
public void whenIdIsNonNull_thenShouldReturnNameUpperCase() throws Exception {
String name = Optional
.ofNullable(personRepository.findNameById("id"))
.map(String::toUpperCase)
.orElseThrow(Exception::new);
assertEquals("NAME", name);
}
}

26
java-streams/.gitignore vendored Normal file
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@ -0,0 +1,26 @@
*.class
0.*
#folders#
/target
/neoDb*
/data
/src/main/webapp/WEB-INF/classes
*/META-INF/*
.resourceCache
# Packaged files #
*.jar
*.war
*.ear
# Files generated by integration tests
*.txt
backup-pom.xml
/bin/
/temp
#IntelliJ specific
.idea/
*.iml

14
java-streams/README.md Normal file
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@ -0,0 +1,14 @@
=========
## Java Streams Cookbooks and Examples
### Relevant Articles:
- [Java 8 Streams Advanced](http://www.baeldung.com/java-8-streams)
- [Introduction to Java 8 Streams](http://www.baeldung.com/java-8-streams-introduction)
- [Java 8 and Infinite Streams](http://www.baeldung.com/java-inifinite-streams)
- [Java 8 Stream findFirst() vs. findAny()](http://www.baeldung.com/java-stream-findfirst-vs-findany)
- [How to Get the Last Element of a Stream in Java?](http://www.baeldung.com/java-stream-last-element)
- [”Stream has already been operated upon or closed” Exception in Java](http://www.baeldung.com/java-stream-operated-upon-or-closed-exception)
- [Iterable to Stream in Java](http://www.baeldung.com/java-iterable-to-stream)
- [How to Iterate Over a Stream With Indices](http://www.baeldung.com/java-stream-indices)
- [Primitive Type Streams in Java 8](http://www.baeldung.com/java-8-primitive-streams)

120
java-streams/pom.xml Normal file
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@ -0,0 +1,120 @@
<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</groupId>
<artifactId>java-streams</artifactId>
<version>0.1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<name>java-streams</name>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-java</artifactId>
<version>0.0.1-SNAPSHOT</version>
<relativePath>../parent-java</relativePath>
</parent>
<dependencies>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>${commons-lang3.version}</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>${log4j.version}</version>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>${lombok.version}</version>
<scope>provided</scope>
</dependency>
<!-- test scoped -->
<dependency>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
<version>${assertj.version}</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.codepoetics</groupId>
<artifactId>protonpack</artifactId>
<version>${protonpack.version}</version>
</dependency>
<dependency>
<groupId>io.vavr</groupId>
<artifactId>vavr</artifactId>
<version>${vavr.version}</version>
</dependency>
<dependency>
<groupId>one.util</groupId>
<artifactId>streamex</artifactId>
<version>${streamex.version}</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjrt</artifactId>
<version>${asspectj.version}</version>
</dependency>
<dependency>
<groupId>org.aspectj</groupId>
<artifactId>aspectjweaver</artifactId>
<version>${asspectj.version}</version>
</dependency>
</dependencies>
<build>
<finalName>java-streams</finalName>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>prepare-package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/libs</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
<compilerArgument>-parameters</compilerArgument>
</configuration>
</plugin>
</plugins>
</build>
<properties>
<!-- util -->
<commons-lang3.version>3.5</commons-lang3.version>
<lombok.version>1.16.12</lombok.version>
<vavr.version>0.9.0</vavr.version>
<protonpack.version>1.13</protonpack.version>
<streamex.version>0.6.5</streamex.version>
<joda.version>2.10</joda.version>
<!-- testing -->
<assertj.version>3.6.1</assertj.version>
<asspectj.version>1.8.9</asspectj.version>
</properties>
</project>

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@ -0,0 +1,13 @@
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
<encoder>
<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
</pattern>
</encoder>
</appender>
<root level="INFO">
<appender-ref ref="STDOUT" />
</root>
</configuration>

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@ -0,0 +1,13 @@
*.class
#folders#
/target
/neoDb*
/data
/src/main/webapp/WEB-INF/classes
*/META-INF/*
# Packaged files #
*.jar
*.war
*.ear

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@ -349,6 +349,7 @@
<module>core-java-collections</module>
<module>core-java-io</module>
<module>core-java-8</module>
<module>java-streams</module>
<module>core-java-persistence</module>
<module>core-kotlin</module>
<module>core-groovy</module>
@ -903,6 +904,7 @@
<module>core-java-collections</module>
<module>core-java-io</module>
<module>core-java-8</module>
<module>java-streams</module>
<module>core-groovy</module>
<module>couchbase</module>

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@ -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</groupId>
<artifactId>StreamsOrdering</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
<!-- https://mvnrepository.com/artifact/org.openjdk.jmh/jmh-core -->
<dependency>
<groupId>org.openjdk.jmh</groupId>
<artifactId>jmh-core</artifactId>
<version>1.21</version>
</dependency>
<dependency>
<groupId>org.openjdk.jmh</groupId>
<artifactId>jmh-generator-annprocess</artifactId>
<version>1.21</version>
<scope>provided</scope>
</dependency>
</dependencies>
</project>

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@ -0,0 +1,148 @@
import org.junit.Before;
import org.junit.Test;
import java.util.*;
import java.util.function.Function;
import java.util.logging.Level;
import java.util.logging.Logger;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import static org.junit.Assert.assertEquals;
public class StreamsOrderingTest {
Logger logger = Logger.getLogger( StreamsOrderingTest.class.getName());
@Before
public void setUp() throws Exception {
logger.setLevel(Level.ALL);
}
@Test
public void givenTwoCollections_whenStreamed_thenCheckOutputDifferent(){
List<String> list = Arrays.asList("B", "A", "C", "D", "F");
Set<String> set = new TreeSet<>(Arrays.asList("B", "A", "C", "D", "F"));
Object[] listOutput = list.stream().toArray();
Object[] setOutput = set.stream().toArray();
assertEquals("[B, A, C, D, F]", Arrays.toString(listOutput));
assertEquals("[A, B, C, D, F]", Arrays.toString(setOutput));
}
@Test
public void givenTwoCollections_whenStreamedInParallel_thenCheckOutputDifferent(){
List<String> list = Arrays.asList("B", "A", "C", "D", "F");
Set<String> set = new TreeSet<>(Arrays.asList("B", "A", "C", "D", "F"));
Object[] listOutput = list.stream().parallel().toArray();
Object[] setOutput = set.stream().parallel().toArray();
assertEquals("[B, A, C, D, F]", Arrays.toString(listOutput));
assertEquals("[A, B, C, D, F]", Arrays.toString(setOutput));
}
@Test
public void givenOrderedInput_whenUnorderedAndOrderedCompared_thenCheckUnorderedOutputChanges(){
Set<Integer> set = new TreeSet<>(
Arrays.asList(-9, -5, -4, -2, 1, 2, 4, 5, 7, 9, 12, 13, 16, 29, 23, 34, 57, 68, 90, 102, 230));
Object[] orderedArray = set.stream()
.parallel()
.limit(5)
.toArray();
Object[] unorderedArray = set.stream()
.unordered()
.parallel()
.limit(5)
.toArray();
logger.info(Arrays.toString(orderedArray));
logger.info(Arrays.toString(unorderedArray));
}
@Test
public void givenUnsortedStreamInput_whenStreamSorted_thenCheckOrderChanged(){
List<Integer> list = Arrays.asList(-3,10,-4,1,3);
Object[] listOutput = list.stream().toArray();
Object[] listOutputSorted = list.stream().sorted().toArray();
assertEquals("[-3, 10, -4, 1, 3]", Arrays.toString(listOutput));
assertEquals("[-4, -3, 1, 3, 10]", Arrays.toString(listOutputSorted));
}
@Test
public void givenUnsortedStreamInput_whenStreamDistinct_thenShowTimeTaken(){
long start, end;
start = System.currentTimeMillis();
IntStream.range(1,1_000_000).unordered().parallel().distinct().toArray();
end = System.currentTimeMillis();
System.out.println(String.format("Time taken when unordered: %d ms", (end - start)));
}
@Test
public void givenSameCollection_whenStreamTerminated_thenCheckEachVsEachOrdered(){
List<String> list = Arrays.asList("B", "A", "C", "D", "F");
list.stream().parallel().forEach(e -> logger.log(Level.INFO, e));
list.stream().parallel().forEachOrdered(e -> logger.log(Level.INFO, e));
}
@Test
public void givenSameCollection_whenStreamCollected_thenCheckOutput(){
List<String> list = Arrays.asList("B", "A", "C", "D", "F");
List<String> collectionList = list.stream().parallel().collect(Collectors.toList());
Set<String> collectionSet = list.stream().parallel().collect(Collectors.toCollection(TreeSet::new));
assertEquals("[B, A, C, D, F]", collectionList.toString());
assertEquals("[A, B, C, D, F]", collectionSet.toString());
}
@Test
public void givenListIterationOrder_whenStreamCollectedToMap_thenCeckOrderChanged() {
List<String> list = Arrays.asList("A", "BB", "CCC");
Map<String, Integer> hashMap = list.stream().collect(Collectors.toMap(Function.identity(), String::length));
Object[] keySet = hashMap.keySet().toArray();
assertEquals("[BB, A, CCC]", Arrays.toString(keySet));
}
@Test
public void givenListIteration_whenStreamCollectedtoHashMap_thenCheckOrderMaintained() {
List<String> list = Arrays.asList("A", "BB", "CCC", "CCC");
Map<String, Integer> linkedHashMap = list.stream().collect(Collectors.toMap(
Function.identity(),
String::length,
(u, v) -> u,
LinkedHashMap::new
));
Object[] keySet = linkedHashMap.keySet().toArray();
assertEquals("[A, BB, CCC]", Arrays.toString(keySet));
}
}

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@ -0,0 +1,97 @@
package benchmarking;
import org.junit.Test;
import org.openjdk.jmh.annotations.*;
import org.openjdk.jmh.infra.Blackhole;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;
import org.openjdk.jmh.runner.options.TimeValue;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.TimeUnit;
import java.util.stream.IntStream;
public class TestBenchmark
{
@Test
public void
launchBenchmark() throws Exception {
Options opt = new OptionsBuilder()
// Specify which benchmarks to run.
// You can be more specific if you'd like to run only one benchmark per test.
.include(this.getClass().getName() + ".*")
// Set the following options as needed
.mode (Mode.AverageTime)
.timeUnit(TimeUnit.MICROSECONDS)
.warmupTime(TimeValue.seconds(1))
.warmupIterations(2)
.measurementTime(TimeValue.seconds(1))
.measurementIterations(2)
.threads(2)
.forks(1)
.shouldFailOnError(true)
.shouldDoGC(true)
//.jvmArgs("-XX:+UnlockDiagnosticVMOptions", "-XX:+PrintInlining")
//.addProfiler(WinPerfAsmProfiler.class)
.build();
new Runner(opt).run();
}
@Benchmark
public void givenOrderedStreamInput_whenStreamFiltered_showOpsPerMS(){
IntStream.range(1, 100_000_000).parallel().filter(i -> i % 10 == 0).toArray();
}
@Benchmark
public void givenUnorderedStreamInput_whenStreamFiltered_showOpsPerMS(){
IntStream.range(1,100_000_000).unordered().parallel().filter(i -> i % 10 == 0).toArray();
}
@Benchmark
public void givenUnorderedStreamInput_whenStreamDistinct_showOpsPerMS(){
IntStream.range(1, 1_000_000).unordered().parallel().distinct().toArray();
}
@Benchmark
public void givenOrderedStreamInput_whenStreamDistinct_showOpsPerMS() {
//section 5.1.
IntStream.range(1, 1_000_000).parallel().distinct().toArray();
}
// The JMH samples are the best documentation for how to use it
// http://hg.openjdk.java.net/code-tools/jmh/file/tip/jmh-samples/src/main/java/org/openjdk/jmh/samples/
@State(Scope.Thread)
public static class BenchmarkState
{
List<Integer> list;
@Setup(Level.Trial) public void
initialize() {
Random rand = new Random();
list = new ArrayList<>();
for (int i = 0; i < 1000; i++)
list.add (rand.nextInt());
}
}
@Benchmark public void
benchmark1 (BenchmarkState state, Blackhole bh) {
List<Integer> list = state.list;
for (int i = 0; i < 1000; i++)
bh.consume (list.get (i));
}
}