1.3.4 Fork/Join框架

package com.study.forkjoin;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ForkJoinPool;
import java.util.concurrent.ForkJoinTask;
import java.util.concurrent.RecursiveTask;

public class ForkJoinTest {

	static ArrayList<String> urls = new ArrayList<String>() {
		{
			add("http://www.baidu.com");
			add("http://www.sina.com");
			add("http://www.baidu.com");
			add("http://www.sina.com");
			add("http://www.baidu.com");
			add("http://www.sina.com");
			add("http://www.baidu.com");
			add("http://www.sina.com");
			add("http://www.baidu.com");
		}
	};

	static ForkJoinPool firkJoinPool = new ForkJoinPool(3, ForkJoinPool.defaultForkJoinWorkerThreadFactory, null, true);

	public static void main(String args[]) throws ExecutionException, InterruptedException {
		Job job = new Job(urls, 0, urls.size());
		ForkJoinTask<String> forkJoinTask = firkJoinPool.submit(job);

		String result = forkJoinTask.get();
		System.out.println(result);
	}

	public static String doRequest(String url) {
		// 模拟网络请求
		return "Kody ... test ... " + url + "\n";
	}

	static class Job extends RecursiveTask<String> {

		List<String> urls;
		int start;
		int end;

		public Job(List<String> urls, int start, int end) {
			this.urls = urls;
			this.start = start;
			this.end = end;
		}

		@Override
		protected String compute() {
			// 计算任务的大小
			int count = end - start;
　　　　　　　　　　　　　　// 指定拆分逻辑即可，递归拆分由框架实现
			if (count <= 5) {
				// 直接执行
				String result = "";
				for (int i = start; i < end; i++) {
					String response = doRequest(urls.get(i));
					result += response;
				}
				return result;
			} else {
				// 继续拆分任务
				int x = (start + end) / 2;

				Job job1 = new Job(urls, start, x);
				job1.fork();

				Job job2 = new Job(urls, x, end);
				job2.fork();

				// 固定写法
				String result = "";
				result += job1.join();
				result += job2.join();
				return result;
			}
		}
	}

}