NO.10 Callable与Future的应用

代码：

package thread;

import java.util.Random;
import java.util.concurrent.Callable;
import java.util.concurrent.CompletionService;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;

public class CallableAndFature {

    /**
     * @param args
     * @throws ExecutionException 
     * @throws InterruptedException 
     */
    public static void main(String[] args) throws InterruptedException, ExecutionException {
        
        /**
         * code 1
         */
        ExecutorService  pool = Executors.newSingleThreadExecutor();
        Future<String> future =
        pool.submit(new Callable<String>() {

            @Override
            public String call() throws Exception {
                Thread.sleep(2000);
                return "hello";
            }
        });
        System.out.println(future.get());
        pool.shutdown();
        
        /**
         * code 2
         */
        ExecutorService  pool2 = Executors.newFixedThreadPool(5);
        
        CompletionService<Integer> server = new ExecutorCompletionService<Integer>(pool2);
        for(int i = 1; i <= 10; i ++) {
            final int seq = i;
            server.submit(new Callable<Integer>() {
                @Override
                public Integer call() throws Exception {
                    Thread.sleep(new Random().nextInt(5000));
                    return seq;
                }
            });
        }
        for(int i = 1; i <= 10; i ++) {
            System.out.println(server.take().get());
        }
        
        
    }

}