Java: Parallel.For

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public class Parallel {     private static final int NUM_CORES = Runtime.getRuntime().availableProcessors();       private static final ExecutorService forPool = Executors.newFixedThreadPool(NUM_CORES  * 2);       public static void For(final Iterable<T> elements, final Operation<T> operation) {         try {             // invokeAll blocks for us until all submitted tasks in the call complete             forPool.invokeAll(createCallables(elements, operation));         } catch (InterruptedException e) {             e.printStackTrace();         }     }       public static Collection<Callable<Void>> createCallables(final Iterable<T> elements, final Operation<T> operation) {         List<Callable<Void>> callables = new LinkedList<Callable<Void>>();         for (final T elem : elements) {             callables.add(new Callable<Void>() {                 @Override                 public Void call() {                     operation.perform(elem);                     return null;                 }             });         }           return callables;     }       public static interface Operation<T> {         public void perform(T pParameter);     } }

Usage:

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// Collection of items to process in parallel Collection<Integer> elems = new LinkedList<Integer>(); for (int i = 0; i < 40; ++i) {     elems.add(i); } Parallel.For(elems,  // The operation to perform with each item  new Parallel.Operation<Integer>() {     public void perform(Integer param) {         System.out.println(param);     }; });