JEP 473: Stream Gatherers

Author: ibrahimatay

README.md

@@ -15,7 +15,9 @@ This repository contains Java examples that are designed to track and document t
   * [JEP 474](java-23/src/main/java/com/ibrahimatay/JEP474ZGCGenerationalModeByDefault.sh): ZGC: Generational Mode by Default
   * [JEP 476](java-23/src/main/java/com/ibrahimatay/JEP476ModuleImportDeclarations.java): Module Import Declarations]
   * [JEP 477](java-23/src/main/java/com/ibrahimatay/JEP477ImplicitlyDeclaredClassesAndInstanceMainMethods.java): Implicitly Declared Classes and Instance Main Methods
-
+  * API Improvements
+    * [JEP 473](java-23/src/main/java/com/ibrahimatay/StreamGathererMethod.java): Stream Gatherers
+    
 * [Java 22](java-22/) (March, 2024)
   * [JEP 458](java-22/src/main/java/com/ibrahimatay/JEP458LaunchMultiFileSourceCode.java): Launch Multi-File Source-Code Programs
 

java-23/src/main/java/com/ibrahimatay/StreamGathererMethod.java

@@ -0,0 +1,31 @@
+package com.ibrahimatay;
+
+import java.util.List;
+import java.util.stream.Gatherers;
+import java.util.stream.Stream;
+
+public class StreamGathererMethod {
+    public static void main(String[] args) {
+        // JEP 473: Stream Gatherers (Second Preview)
+        // https://openjdk.org/jeps/473
+
+        List<Integer> numbers = List.of(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
+
+        List<List<Integer>> pairedEvenSquares = numbers.stream()
+                .filter(n -> n % 2 == 0)
+                .map(n -> n * n)
+                .gather(Gatherers.windowFixed(2))
+                .toList();
+
+        System.out.println(pairedEvenSquares);
+        // [[4, 16], [36, 64], [100]]
+
+        List<List<Integer>> windowsOfThree
+                = Stream.of(0,1,2,3,4,5,6,7)
+                .gather(Gatherers.windowFixed(3))
+                .toList();
+
+        System.out.println(windowsOfThree);
+        // [[0, 1, 2], [3, 4, 5], [6, 7]]
+    }
+}