diff --git a/core-java-modules/core-java-8/src/main/java/com/baeldung/spliterator/CustomSpliterator.java b/core-java-modules/core-java-8/src/main/java/com/baeldung/spliterator/CustomSpliterator.java new file mode 100644 index 0000000000..2f806cccda --- /dev/null +++ b/core-java-modules/core-java-8/src/main/java/com/baeldung/spliterator/CustomSpliterator.java @@ -0,0 +1,48 @@ +package com.baeldung.spliterator; + +import java.util.List; +import java.util.Spliterator; +import java.util.function.Consumer; + +public class CustomSpliterator implements Spliterator { + private final List elements; + private int currentIndex; + + public CustomSpliterator(List elements) { + this.elements = elements; + this.currentIndex = 0; + } + + @Override + public boolean tryAdvance(Consumer action) { + if (currentIndex < elements.size()) { + action.accept(elements.get(currentIndex)); + currentIndex++; + return true; + } + return false; + } + + @Override + public Spliterator trySplit() { + int currentSize = elements.size() - currentIndex; + if (currentSize < 2) { + return null; + } + + int splitIndex = currentIndex + currentSize / 2; + CustomSpliterator newSpliterator = new CustomSpliterator(elements.subList(currentIndex, splitIndex)); + currentIndex = splitIndex; + return newSpliterator; + } + + @Override + public long estimateSize() { + return elements.size() - currentIndex; + } + + @Override + public int characteristics() { + return ORDERED | SIZED | SUBSIZED | NONNULL; + } +} \ No newline at end of file diff --git a/core-java-modules/core-java-8/src/main/java/com/baeldung/spliterator/Executor.java b/core-java-modules/core-java-8/src/main/java/com/baeldung/spliterator/Executor.java deleted file mode 100644 index 3dc2fa06bb..0000000000 --- a/core-java-modules/core-java-8/src/main/java/com/baeldung/spliterator/Executor.java +++ /dev/null @@ -1,12 +0,0 @@ -package com.baeldung.spliterator; - -import java.util.stream.Stream; - -public class Executor { - - public static int countAutors(Stream stream) { - RelatedAuthorCounter wordCounter = stream.reduce(new RelatedAuthorCounter(0, true), - RelatedAuthorCounter::accumulate, RelatedAuthorCounter::combine); - return wordCounter.getCounter(); - } -} \ No newline at end of file diff --git a/core-java-modules/core-java-8/src/main/java/com/baeldung/spliterator/RelatedAuthorCounter.java b/core-java-modules/core-java-8/src/main/java/com/baeldung/spliterator/RelatedAuthorCounter.java deleted file mode 100644 index 8800eac55b..0000000000 --- a/core-java-modules/core-java-8/src/main/java/com/baeldung/spliterator/RelatedAuthorCounter.java +++ /dev/null @@ -1,27 +0,0 @@ -package com.baeldung.spliterator; - -public class RelatedAuthorCounter { - private final int counter; - private final boolean isRelated; - - public RelatedAuthorCounter(int counter, boolean isRelated) { - this.counter = counter; - this.isRelated = isRelated; - } - - public RelatedAuthorCounter accumulate(Author author) { - if (author.getRelatedArticleId() == 0) { - return isRelated ? this : new RelatedAuthorCounter(counter, true); - } else { - return isRelated ? new RelatedAuthorCounter(counter + 1, false) : this; - } - } - - public RelatedAuthorCounter combine(RelatedAuthorCounter RelatedAuthorCounter) { - return new RelatedAuthorCounter(counter + RelatedAuthorCounter.counter, RelatedAuthorCounter.isRelated); - } - - public int getCounter() { - return counter; - } -} diff --git a/core-java-modules/core-java-8/src/main/java/com/baeldung/spliterator/RelatedAuthorSpliterator.java b/core-java-modules/core-java-8/src/main/java/com/baeldung/spliterator/RelatedAuthorSpliterator.java deleted file mode 100644 index 93c83b8127..0000000000 --- a/core-java-modules/core-java-8/src/main/java/com/baeldung/spliterator/RelatedAuthorSpliterator.java +++ /dev/null @@ -1,49 +0,0 @@ -package com.baeldung.spliterator; - -import java.util.List; -import java.util.Spliterator; -import java.util.concurrent.atomic.AtomicInteger; -import java.util.function.Consumer; - -public class RelatedAuthorSpliterator implements Spliterator { - private final List list; - AtomicInteger current = new AtomicInteger(); - - public RelatedAuthorSpliterator(List list) { - this.list = list; - } - - @Override - public boolean tryAdvance(Consumer action) { - - action.accept(list.get(current.getAndIncrement())); - return current.get() < list.size(); - } - - @Override - public Spliterator trySplit() { - int currentSize = list.size() - current.get(); - if (currentSize < 10) { - return null; - } - for (int splitPos = currentSize / 2 + current.intValue(); splitPos < list.size(); splitPos++) { - if (list.get(splitPos).getRelatedArticleId() == 0) { - Spliterator spliterator = new RelatedAuthorSpliterator(list.subList(current.get(), splitPos)); - current.set(splitPos); - return spliterator; - } - } - return null; - } - - @Override - public long estimateSize() { - return list.size() - current.get(); - } - - @Override - public int characteristics() { - return CONCURRENT; - } - -} diff --git a/core-java-modules/core-java-8/src/test/java/com/baeldung/spliterator/ExecutorUnitTest.java b/core-java-modules/core-java-8/src/test/java/com/baeldung/spliterator/ExecutorUnitTest.java index 4628f95481..30760ddf6f 100644 --- a/core-java-modules/core-java-8/src/test/java/com/baeldung/spliterator/ExecutorUnitTest.java +++ b/core-java-modules/core-java-8/src/test/java/com/baeldung/spliterator/ExecutorUnitTest.java @@ -6,10 +6,10 @@ import java.util.ArrayList; import java.util.Arrays; import java.util.List; import java.util.Spliterator; +import java.util.concurrent.ForkJoinPool; +import java.util.concurrent.atomic.AtomicInteger; import java.util.stream.Collectors; import java.util.stream.Stream; -import java.util.stream.StreamSupport; - import org.junit.Before; import org.junit.Test; @@ -18,22 +18,50 @@ import lombok.extern.slf4j.Slf4j; @Slf4j public class ExecutorUnitTest { Article article; - Stream stream; - Spliterator spliterator; @Before public void init() { article = new Article(Arrays.asList(new Author("Ahmad", 0), new Author("Eugen", 0), new Author("Alice", 1), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Alice", 1), new Author("Mike", 0), new Author("Michał", 0), new Author("Loredana", 1)), 0); - - spliterator = new RelatedAuthorSpliterator(article.getListOfAuthors()); } @Test - public void givenAstreamOfAuthors_whenProcessedInParallelWithCustomSpliterator_coubtProducessRightOutput() { - Stream stream2 = StreamSupport.stream(spliterator, true); - assertThat(Executor.countAutors(stream2.parallel())).isEqualTo(9); + public void givenAStreamOfIntegers_whenProcessedSequentialCustomSpliterator_countProducesRightOutput() { + List numbers = new ArrayList<>(); + numbers.add(1); + numbers.add(2); + numbers.add(3); + numbers.add(4); + numbers.add(5); + + CustomSpliterator customSpliterator = new CustomSpliterator(numbers); + + AtomicInteger sum = new AtomicInteger(); + + customSpliterator.forEachRemaining(sum::addAndGet); + assertThat(sum.get()).isEqualTo(15); + } + + @Test + public void givenAStreamOfIntegers_whenProcessedInParallelWithCustomSpliterator_countProducesRightOutput() { + List numbers = new ArrayList<>(); + numbers.add(1); + numbers.add(2); + numbers.add(3); + numbers.add(4); + numbers.add(5); + + CustomSpliterator customSpliterator = new CustomSpliterator(numbers); + + // Create a ForkJoinPool for parallel processing + ForkJoinPool forkJoinPool = ForkJoinPool.commonPool(); + + AtomicInteger sum = new AtomicInteger(0); + + // Process elements in parallel using parallelStream + forkJoinPool.submit(() -> customSpliterator.forEachRemaining(sum::addAndGet)).join(); + assertThat(sum.get()).isEqualTo(15); } @Test @@ -43,9 +71,7 @@ public class ExecutorUnitTest { .collect(Collectors.toList()); Spliterator
spliterator = articles.spliterator(); - while (spliterator.tryAdvance(article -> article.setName(article.getName() - .concat("- published by Baeldung")))) - ; + while(spliterator.tryAdvance(article -> article.setName(article.getName().concat("- published by Baeldung")))); articles.forEach(article -> assertThat(article.getName()).isEqualTo("Java- published by Baeldung")); }