系列十三、分支合并框架

一、概述

Fork：把一个复杂任务进行分拆，大事化小，Join：把分拆任务的结果进行合并

二、相关类

2.1、ForkJoinPool 

分支合并池，类比线程池。

2.2、ForkJoinTask

ForkJoinTask，类比 FutureTask。

2.3、RecursiveTask

递归任务：继承后可以实现递归(自己调自己)调用的任务

2.4、案例代码

2.4.1、MyRecursiveTask

/**
 * @Author : 一叶浮萍归大海
 * @Date: 2023/11/21 10:10
 * @Description:
 */
public class MyRecursiveTask extends RecursiveTask {
    private static final Integer ADJUST_VALUE = 10;
    private int begin;
    private int end;
    private int result;

    public MyRecursiveTask(int begin, int end) {
        this.begin = begin;
        this.end = end;
    }

    @Override
    protected Integer compute() {
        if ((end - begin) <= ADJUST_VALUE) {
            for (int i = begin; i <= end; i++) {
                result += i;
            }
            System.out.println("(end - begin) result : " + result);
        } else {
            int middle = (begin + end) / 2;
            MyRecursiveTask task1 = new MyRecursiveTask(begin, middle);
            MyRecursiveTask task2 = new MyRecursiveTask(middle + 1, end);
            task1.fork();
            task2.fork();
            result = task1.join() + task2.join();
            System.out.println("(end + begin)/2 result : " + result);
        }

        return result;
    }
}

2.4.2、RecursiveTaskMainApp

/**
 * @Author : 一叶浮萍归大海
 * @Date: 2023/11/21 10:12
 * @Description: 分支合并案例代码
 */
public class RecursiveTaskMainApp {

    public static void main(String[] args) throws ExecutionException, InterruptedException {

        MyRecursiveTask task = new MyRecursiveTask(1,100);
        ForkJoinPool forkJoinPool = new ForkJoinPool();
        ForkJoinTask forkJoinTask = forkJoinPool.submit(task);

        System.out.println(forkJoinTask.get());

        forkJoinPool.shutdown();
    }

}