package Search;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.atomic.AtomicInteger;

public class SearchMain {
	static ExecutorService pool = Executors.newCachedThreadPool();
	static final int THREAD_NUM = 2;
	// 存放结果,保存符合条件元素的下标。
	static AtomicInteger result = new AtomicInteger(-1);
	static int[] arr = new int[] { 1, 32, 33, 56, 87, 43 };

	public static void main(String[] args) throws InterruptedException, ExecutionException {
		System.out.println(arr.length);
		Thread.sleep(3000);
		System.out.println(pSearch(1));

	}

	/**
	 * 并行查找函数 根据数据线程数量对arr数组进行划分,并建立对应的任务提交给线程池处理
	 */
	public static int pSearch(int searchValue) throws InterruptedException, ExecutionException {
		int subArrSize = arr.length / THREAD_NUM + 1;
		List<Future<Integer>> re = new ArrayList<Future<Integer>>();
		for (int i = 0; i < arr.length; i += subArrSize) {
			int end = i + subArrSize;
			if (end >= arr.length) {
				end = arr.length;
			}
			re.add(pool.submit(new SearchTask(i, end, searchValue)));
		}
		for (Future<Integer> future : re) {
			if (future.get() >= 0) {
				return future.get();
			}
		}
		return -1;
	}

	/**
	 * 并发搜索 要求每个线程查找arr中的一段
	 */
	public static int search(int searchValue, int startPos, int endPos) {
		int i = 0;
		for (i = startPos; i < endPos; i++) {
			if (result.get() >= 0) {
				return result.get();
			}
			if (arr[i] == searchValue) {
				// 如果设置失败,表示其他线程已经先找到了
				if (!result.compareAndSet(-1, i)) {
					System.out.println("如果设置失败,表示其他线程已经先找到了");
					return result.get();
				}
				System.out.println("jjy");
				return i;
			}
		}
		System.out.println("lxf");
		return -1;
	}

	public static class SearchTask implements Callable<Integer> {
		int begin, end, searchValue;

		@Override
		public Integer call() throws Exception {
			int re = search(searchValue, begin, end);
			return re;
		}

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

	}
}