主要用于并行計算中抡砂，和 MapReduce 原理類似菜循，都是把大的計算任務(wù)拆分成多個小任務(wù)并行計算趾断。
public class ForkJoinExample extends RecursiveTask<Integer> {
private final int threhold = 5;
private int first;
private int last;
public ForkJoinExample(int first, int last) {
this.first = first;
this.last = last;
}
@Override
protected Integer compute() {
int result = 0;
if (last - first <= threhold) {
// 任務(wù)足夠小則直接計算
for (int i = first; i <= last; i++) {
result += i;
}
} else {
// 拆分成小任務(wù)
int middle = first + (last - first) / 2;
ForkJoinExample leftTask = new ForkJoinExample(first, middle);
ForkJoinExample rightTask = new ForkJoinExample(middle + 1, last);
leftTask.fork();
rightTask.fork();
result = leftTask.join() + rightTask.join();
}
return result;
}
}
public static void main(String[] args) throws ExecutionException, InterruptedException {
ForkJoinExample example = new ForkJoinExample(1, 10000);
ForkJoinPool forkJoinPool = new ForkJoinPool();
Future result = forkJoinPool.submit(example);
System.out.println(result.get());
}
