JAVA-23808 Rewrite Custom Spliterator Section of Introduction to Spliterator Article

2023-10-21 20:10:35 +03:00
parent b0ed62e8c8
commit 1a7d3aff21
5 changed files with 86 additions and 100 deletions
@@ -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<Integer> {
+    private final List<Integer> elements;
+    private int currentIndex;
+    
+    public CustomSpliterator(List<Integer> elements) {
+        this.elements = elements;
+        this.currentIndex = 0;
+    }
+    
+    @Override
+    public boolean tryAdvance(Consumer<? super Integer> action) {
+        if (currentIndex < elements.size()) {
+            action.accept(elements.get(currentIndex));
+            currentIndex++;
+            return true;
+        }
+        return false;
+    }
+    
+    @Override
+    public Spliterator<Integer> 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;
+    }
+} 
@@ -1,12 +0,0 @@
-package com.baeldung.spliterator;
-
-import java.util.stream.Stream;
-
-public class Executor {
-
-	public static int countAutors(Stream<Author> stream) {
-		RelatedAuthorCounter wordCounter = stream.reduce(new RelatedAuthorCounter(0, true),
-				RelatedAuthorCounter::accumulate, RelatedAuthorCounter::combine);
-		return wordCounter.getCounter();
-	}
-}
@@ -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;
-    }
-}
@@ -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<Author> {
-	private final List<Author> list;
-	AtomicInteger current = new AtomicInteger();
-
-	public RelatedAuthorSpliterator(List<Author> list) {
-		this.list = list;
-	}
-
-	@Override
-	public boolean tryAdvance(Consumer<? super Author> action) {
-
-		action.accept(list.get(current.getAndIncrement()));
-		return current.get() < list.size();
-	}
-
-	@Override
-	public Spliterator<Author> 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<Author> 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;
-	}
-
-}