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Split or move java-streams module

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This commit is contained in:
catalin-burcea
2019-10-27 11:09:34 +02:00
parent 699cc1027e
commit 62089a7abb
67 changed files with 881 additions and 1046 deletions
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6
core-java-modules/core-java-9-streams/README.md Normal file
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## Core Java 9 streams
This module contains articles about Java 9 streams
### Relevant Articles:
- [How to Break from Java Stream forEach](https://www.baeldung.com/java-break-stream-foreach)

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core-java-modules/core-java-9-streams/pom.xml Normal file
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<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>
<artifactId>core-java-9-streams</artifactId>
<version>0.1.0-SNAPSHOT</version>
<name>core-java-9-streams</name>
<packaging>jar</packaging>
<parent>
<groupId>com.baeldung</groupId>
<artifactId>parent-java</artifactId>
<version>0.0.1-SNAPSHOT</version>
<relativePath>../../parent-java</relativePath>
</parent>
<dependencies>
</dependencies>
<build>
<finalName>core-java-9-streams</finalName>
<resources>
<resource>
<directory>src/main/resources</directory>
<filtering>true</filtering>
</resource>
</resources>
</build>
<properties>
</properties>
</project>

32
core-java-modules/core-java-9-streams/src/main/java/com/baeldung/streams/breakforeach/CustomForEach.java Normal file
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package com.baeldung.streams.breakforeach;
import java.util.Spliterator;
import java.util.function.BiConsumer;
import java.util.stream.Stream;
public class CustomForEach {
public static class Breaker {
private boolean shouldBreak = false;
public void stop() {
shouldBreak = true;
}
boolean get() {
return shouldBreak;
}
}
public static <T> void forEach(Stream<T> stream, BiConsumer<T, Breaker> consumer) {
Spliterator<T> spliterator = stream.spliterator();
boolean hadNext = true;
Breaker breaker = new Breaker();
while (hadNext && !breaker.get()) {
hadNext = spliterator.tryAdvance(elem -> {
consumer.accept(elem, breaker);
});
}
}
}

31
core-java-modules/core-java-9-streams/src/main/java/com/baeldung/streams/breakforeach/CustomSpliterator.java Normal file
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package com.baeldung.streams.breakforeach;
import java.util.Spliterator;
import java.util.Spliterators;
import java.util.function.Consumer;
import java.util.function.Predicate;
public class CustomSpliterator<T> extends Spliterators.AbstractSpliterator<T> {
private Spliterator<T> splitr;
private Predicate<T> predicate;
private boolean isMatched = true;
public CustomSpliterator(Spliterator<T> splitr, Predicate<T> predicate) {
super(splitr.estimateSize(), 0);
this.splitr = splitr;
this.predicate = predicate;
}
@Override
public boolean tryAdvance(Consumer<? super T> consumer) {
boolean hadNext = splitr.tryAdvance(elem -> {
if (predicate.test(elem) && isMatched) {
consumer.accept(elem);
} else {
isMatched = false;
}
});
return hadNext && isMatched;
}
}

14
core-java-modules/core-java-9-streams/src/main/java/com/baeldung/streams/breakforeach/CustomTakeWhile.java Normal file
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package com.baeldung.streams.breakforeach;
import java.util.function.Predicate;
import java.util.stream.Stream;
import java.util.stream.StreamSupport;
public class CustomTakeWhile {
public static <T> Stream<T> takeWhile(Stream<T> stream, Predicate<T> predicate) {
CustomSpliterator<T> customSpliterator = new CustomSpliterator<>(stream.spliterator(), predicate);
return StreamSupport.stream(customSpliterator, false);
}
}

26
core-java-modules/core-java-9-streams/src/main/java/com/baeldung/streams/breakforeach/TakeWhileExample.java Normal file
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package com.baeldung.streams.breakforeach;
import java.util.List;
import java.util.stream.Stream;
import static java.util.Arrays.asList;
public class TakeWhileExample {
public static void takeWhileJava9() {
Stream.of("cat", "dog", "elephant", "fox", "rabbit", "duck")
.takeWhile(n -> n.length() % 2 != 0)
.forEach(System.out::println); // cat, dog
}
public static void plainForLoopWithBreak() {
List<String> list = asList("cat", "dog", "elephant", "fox", "rabbit", "duck");
for (int i = 0; i < list.size(); i++) {
String item = list.get(i);
if (item.length() % 2 == 0) {
break;
}
System.out.println(item);
}
}
}

41
core-java-modules/core-java-9-streams/src/test/java/com/baeldung/streams/breakforeach/BreakFromStreamForEachUnitTest.java Normal file
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package com.baeldung.streams.breakforeach;
import org.junit.Test;
import java.util.ArrayList;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import static java.util.Arrays.asList;
import static org.junit.Assert.assertEquals;
public class BreakFromStreamForEachUnitTest {
@Test
public void whenCustomTakeWhileIsCalled_ThenCorrectItemsAreReturned() {
Stream<String> initialStream = Stream.of("cat", "dog", "elephant", "fox", "rabbit", "duck");
List<String> result = CustomTakeWhile.takeWhile(initialStream, x -> x.length() % 2 != 0)
.collect(Collectors.toList());
assertEquals(asList("cat", "dog"), result);
}
@Test
public void whenCustomForEachIsCalled_ThenCorrectItemsAreReturned() {
Stream<String> initialStream = Stream.of("cat", "dog", "elephant", "fox", "rabbit", "duck");
List<String> result = new ArrayList<>();
CustomForEach.forEach(initialStream, (elem, breaker) -> {
if (elem.length() % 2 == 0) {
breaker.stop();
} else {
result.add(elem);
}
});
assertEquals(asList("cat", "dog"), result);
}
}