package com.drighetto.pp;
import java.io.File;
import java.util.concurrent.TimeUnit;
import jsr166y.ForkJoinPool;
import jsr166y.ForkJoinTask;
import com.drighetto.pp.task.FileCounterRecursiveAction;
/**
* First sample : Launch several tasks (the type of task used here do not return
* results) and wait for their termination...<br>
* In this sample the tasks do not have link between them and the result of a
* task is not used by another...<br>
* <br>
*
* @see "http://gee.cs.oswego.edu/dl/jsr166/dist/jsr166ydocs/jsr166y/ForkJoinPool.html"
*
* @author Dominique Righetto (dominique.righetto@gmail.com)
*
*/
public class Sample01 {
/**
* Entry point
*
* @param args
* Command line
* @throws Exception
*/
public static void main(String[] args) throws Exception {
/* Create and configure a task pool manager (task executor) */
ForkJoinPool taskExecutor = new ForkJoinPool();
// Indicate to the task executor to use all processor of the current
// machine
taskExecutor.setParallelism(Runtime.getRuntime().availableProcessors());
// In this sample tasks used here do not joined the we can disable the
// AsyncMode (documentation
// extract :
// Establishes local first-in-first-out scheduling mode for forked tasks
// that are never joined. This mode may be more appropriate than default
// locally stack-based mode in applications in which worker threads only
// process asynchronous tasks. This method is designed to be invoked
// only when the pool is quiescent, and typically only before any tasks
// are submitted. The effects of invocations at other times may be
// unpredictable.)
taskExecutor.setAsyncMode(false);
// Indicate to the task executor to maintain parallelism
taskExecutor.setMaintainsParallelism(true);
/* Create and launch tasks with the task executor */
FileCounterRecursiveAction task01 = new FileCounterRecursiveAction(new File("C:\\"));
FileCounterRecursiveAction task02 = new FileCounterRecursiveAction(new File("D:\\"));
FileCounterRecursiveAction task03 = new FileCounterRecursiveAction(new File("E:\\"));
// Explicit invalid path in order that the task fail !
FileCounterRecursiveAction task04 = new FileCounterRecursiveAction(new File("A:\\"));
taskExecutor.execute(task01);
taskExecutor.execute(task02);
taskExecutor.execute(task03);
taskExecutor.execute(task04);
System.out.println("Tasks launched...");
/* Close the pool */
taskExecutor.shutdown();
/*
* Wait tasks termination (limit waiting to 15 minutes) and then display
* processing state
*/
boolean terminationState = taskExecutor.awaitTermination(15, TimeUnit.MINUTES);
if (terminationState) {
System.out.println("All tasks have finished their processing under the timeout !");
} else {
System.out.println("All tasks do not have finished their processing until the timeout !");
}
System.out.println(" ** Task01 processing status **");
displayTaskProcessingStatus(task01);
System.out.println(" ** Task02 processing status **");
displayTaskProcessingStatus(task02);
System.out.println(" ** Task03 processing status **");
displayTaskProcessingStatus(task03);
System.out.println(" ** Task04 processing status **");
displayTaskProcessingStatus(task04);
}
/**
* Display the processing status of a task
*
* @param task
* source task
*/
@SuppressWarnings("boxing")
private static void displayTaskProcessingStatus(ForkJoinTask<Void> task) {
System.out.printf(" isCompletedNormally() : %s\n", task.isCompletedNormally());
System.out.printf(" isDone() : %s\n", task.isDone());
System.out.printf(" isCancelled() : %s\n", task.isCancelled());
System.out.printf(" isCompletedAbnormally() : %s\n", task.isCompletedAbnormally());
System.out.printf(" getException() : %s\n", (task.getException() == null) ? null : task.getException().getMessage());
}
}