“Parallel.For”for Java？(“Parallel.For” for Java?)

“Parallel.For”for Java？(“Parallel.For” for Java?)

我想知道是否有一个Parallel.For相当于.net版本的Java？

如果有人可以提供一个例子？ 谢谢！

I was wondering if there is a Parallel.For equivalent to the .net version for Java?

If there is could someone please supply an example? thanks!

最满意答案

我猜最近的事情是：

ExecutorService exec = Executors.newFixedThreadPool(SOME_NUM_OF_THREADS); try { for (final Object o : list) { exec.submit(new Runnable() { @Override public void run() { // do stuff with o. } }); } } finally { exec.shutdown(); }

基于TheLQ的注释，您可以将SUM_NUM_THREADS设置为Runtime.getRuntime().availableProcessors();

编辑：决定添加一个基本的“Parallel.For”实现

public class Parallel { private static final int NUM_CORES = Runtime.getRuntime().availableProcessors(); private static final ExecutorService forPool = Executors.newFixedThreadPool(NUM_CORES * 2, new NamedThreadFactory("Parallel.For")); public static <T> 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 <T> 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); } }

Parallel.For的示例用法

// 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); }; });

我猜这个实现真的和Parallel.ForEach更相似

编辑我把它放在GitHub上，如果有人有兴趣的话。 并行在GitHub上

I guess the closest thing would be:

ExecutorService exec = Executors.newFixedThreadPool(SOME_NUM_OF_THREADS); try { for (final Object o : list) { exec.submit(new Runnable() { @Override public void run() { // do stuff with o. } }); } } finally { exec.shutdown(); }

Based on TheLQ's comments, you would set SUM_NUM_THREADS to Runtime.getRuntime().availableProcessors();

Edit: Decided to add a basic "Parallel.For" implementation

public class Parallel { private static final int NUM_CORES = Runtime.getRuntime().availableProcessors(); private static final ExecutorService forPool = Executors.newFixedThreadPool(NUM_CORES * 2, new NamedThreadFactory("Parallel.For")); public static <T> 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 <T> 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); } }

Example Usage of Parallel.For

// 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); }; });

I guess this implementation is really more similar to Parallel.ForEach

Edit I put this up on GitHub if anyone is interested. Parallel For on GitHub