package com.packt.tfesenko.multithreading.section1;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.RecursiveAction;
import java.util.concurrent.TimeUnit;
import java.util.stream.IntStream;
public class Lesson4 {
public static void main(String[] args) throws InterruptedException {
AppleTree[] appleTrees = AppleTree.newTreeGarden(12);
PickFruitAction task = new PickFruitAction(appleTrees, 0, appleTrees.length - 1);
ForkJoinPool pool = ForkJoinPool.commonPool();
pool.invoke(task);
// try this: pool.execute(task);
// try this: pool.execute(task); task.join();
// try this: pool.execute(task); pool.awaitTermination(10, TimeUnit.SECONDS);
System.out.println();
System.out.println("Done!");
}
public static class PickFruitAction extends RecursiveAction {
private final AppleTree[] appleTrees;
private final int startInclusive;
private final int endInclusive;
private final int taskThreadshold = 4;
public PickFruitAction(AppleTree[] array, int startInclusive, int endInclusive) {
this.appleTrees = array;
this.startInclusive = startInclusive;
this.endInclusive = endInclusive;
}
@Override
protected void compute() {
if (endInclusive - startInclusive < taskThreadshold) {
doCompute();
return;
}
int midpoint = startInclusive + (endInclusive - startInclusive) / 2;
PickFruitAction leftSum = new PickFruitAction(appleTrees, startInclusive, midpoint);
PickFruitAction rightSum = new PickFruitAction(appleTrees, midpoint + 1, endInclusive);
rightSum.fork(); // computed asynchronously
leftSum.compute();// computed synchronously: immediately and in the current thread
rightSum.join();
}
protected void doCompute() {
IntStream.rangeClosed(startInclusive, endInclusive)//
.forEach(i -> appleTrees[i].pickApples());
}
}
}
