/*
* Copyright 2011 Matt Crinklaw-Vogt
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package whitebox.utilities;
import java.util.Collection;
import java.util.LinkedList;
import java.util.List;
import java.util.concurrent.*;
public class Parallel {
private static final int NUM_CORES = Runtime.getRuntime().availableProcessors();
private static final ExecutorService forEachPool = Executors.newFixedThreadPool(NUM_CORES * 2, new NamedThreadFactory("Parallel.For"));
private static final ForkJoinPool fjPool = new ForkJoinPool(NUM_CORES, ForkJoinPool.defaultForkJoinWorkerThreadFactory, null, true);
public static <T> void ForEach(final Iterable<T> elements, final Operation<T> operation) {
try {
forEachPool.invokeAll(createCallables(elements, operation));
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public static <T> void ForFJ(final Iterable<T> elements, final Operation<T> operation) {
fjPool.invokeAll(createCallables(elements, operation));
}
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);
}
public static void For(int start, int stop, int step,
final LoopBody<Integer> loopBody) {
ExecutorService executor = Executors.newFixedThreadPool(NUM_CORES);
List<Future<?>> futures = new LinkedList<Future<?>>();
for (int i = start; i < stop; i += step) {
final Integer k = i;
Future<?> future = executor.submit(new Runnable() {
@Override
public void run() {
loopBody.run(k);
}
});
futures.add(future);
}
for (Future<?> f : futures) {
try {
f.get();
} catch (InterruptedException e) {
} catch (ExecutionException e) {
}
}
executor.shutdown();
}
// this is only used for testing the tool
public static void main(String[] args) {
Parallel p = new Parallel();
p.parallelForTest();
}
int k;
private void parallelForTest() {
k = 0;
Parallel.For(0, 100, 5, new LoopBody <Integer>()
{
@Override
public void run(Integer i)
{
k += i;
System.out.println(i);
}
});
System.out.println("Sum = "+ k);
// Collection of items to process in parallel
Collection<Integer> elems = new LinkedList<Integer>();
for (int i = 0; i < 40; ++i) {
elems.add(i);
}
Parallel.ForEach(elems,
// The operation to perform with each item
new Parallel.Operation<Integer>() {
@Override
public void perform(Integer param) {
System.out.println(param);
}
;
});
}
public interface LoopBody <T> {
void run(T i);
}
}