Java class for testing usage of fork-join Actions by GraalVM native image generation.
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package org.fabri1983.eternity2.forkjoin_solver; | |
import java.util.concurrent.CountDownLatch; | |
import java.util.concurrent.ForkJoinPool; | |
import java.util.concurrent.RecursiveAction; | |
/** | |
* This class intended for testing use of fork-join Actions in Graal native image generation. | |
* Building steps: | |
* <pre> | |
* %JAVA_HOME%/bin/javac MainHelloWorldNative.java | |
* %GRAALVM_HOME%/bin/native-image --verbose MainHelloWorldNative | |
* MainHelloWorldNative | |
* </pre> | |
*/ | |
public class MainHelloWorldNative extends RecursiveAction { | |
private static final long serialVersionUID = 1L; | |
final static int NUM_PROCESSES = 4; | |
int tag; | |
CountDownLatch startSignal; | |
CountDownLatch doneSignal; | |
public MainHelloWorldNative(int tag, CountDownLatch startSignal, CountDownLatch doneSignal) { | |
super(); | |
this.tag = tag; | |
this.startSignal = startSignal; | |
this.doneSignal = doneSignal; | |
} | |
@Override | |
protected void compute() { | |
try { | |
// await for starting signal | |
startSignal.await(); | |
// start doing some work | |
System.out.println("Start task " + tag); | |
long count = 0L; | |
for (long x=0, c=Integer.MAX_VALUE; x < c; x++) { | |
count+=1; | |
} | |
System.out.println("Finish task " + tag + " with count " + count); | |
} catch (InterruptedException e) { | |
System.out.println("Exception on compute()"); | |
e.printStackTrace(); | |
} finally { | |
doneSignal.countDown(); | |
} | |
} | |
// arguments are passed using the text field below this editor | |
public static void main(String[] args) { | |
ForkJoinPool fjpool = new ForkJoinPool(NUM_PROCESSES, ForkJoinPool.defaultForkJoinWorkerThreadFactory, null, true); | |
// a start signal that prevents any ExplorationAction from proceeding until the orchestrator (this thread) is | |
// ready for them to proceed | |
final CountDownLatch startSignal = new CountDownLatch(1); | |
// a completion signal that allows the driver orchestrator (this thread) to wait until all ExplorationAction | |
// have completed | |
final CountDownLatch doneSignal = new CountDownLatch(NUM_PROCESSES); | |
// submit all fork join tasks | |
for (int i = 0; i < NUM_PROCESSES; ++i) { | |
System.out.println("RecursiveAction " + i + " submitted"); | |
fjpool.submit(new MainHelloWorldNative(i, startSignal, doneSignal)); | |
} | |
// let all threads proceed | |
startSignal.countDown(); | |
// wait for all tasks to finish | |
try { | |
doneSignal.await(); | |
System.out.println("All tasks have finished!"); | |
} catch (InterruptedException e) { | |
System.out.println("Exception on doneSignal.await()"); | |
e.printStackTrace(); | |
} | |
} | |
} |
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