實戰Memcached快取系統（6）Memcached CAS的多執行緒程式例項

1. 源程式

package com.sinosuperman.memcached;

import java.io.IOException;
import java.net.InetSocketAddress;

import net.spy.memcached.CASResponse;
import net.spy.memcached.CASValue;
import net.spy.memcached.MemcachedClient;


public class Test {
	
	private static MemcachedClient client = null;
	
	static {
		try {
			client = new MemcachedClient(new InetSocketAddress("localhost", 11211));
		} catch (IOException o) {
		}
	}

	public static void main(String[] args) throws Exception {
		
		client.set("numberss", 1800, 1);
		
		Test testObj = new Test();
		for (int i = 0; i < 10; i++) {
			testObj.new ThreadTest("Thread-" + (i + 1)).start();
		}
	}
	
	private class ThreadTest extends Thread {
		
		private  MemcachedClient client = null;
		ThreadTest(String name) throws IOException {
			super(name);
			client = new MemcachedClient(new InetSocketAddress("localhost", 11211));
		}
		
		public void run() {
			int i = 0;
			int success = 0;
			while (i < 10) {
				i++;
				CASValue<Object> uniqueValue =client.gets("numberss");
				CASResponse response = client.cas("numberss",   
                 uniqueValue.getCas(), (Integer)uniqueValue.getValue() + 1);

				if (response.toString().equals("OK")) {
					success++;
				}
				
				if (i == 10)
				System.out.println(Thread.currentThread().getName() + " " +  i 
                  + " time " + " update oldValue : " + uniqueValue.getValue() 
                  +  " , result : " + response);
			}
			
			if (success < 10) {
				Count.incr(10 - success);
				System.out.println("Test counter: " + Count.get());
			}
		}
	}
	
	public static class Count {
		private static int counter = 0;
		public static void incr(int x) {
			counter += x;
		}
		public static int get() {
			return counter;
		}
	}
}

2. 輸出結果：

Thread-1 10 time  update oldValue : 14 , result : EXISTS
Test counter: 6
Thread-2 10 time  update oldValue : 14 , result : EXISTS
Test counter: 15
Thread-3 10 time  update oldValue : 17 , result : EXISTS
Test counter: 22
Thread-5 10 time  update oldValue : 17 , result : EXISTS
Test counter: 27
Thread-4 10 time  update oldValue : 20 , result : OK
Test counter: 33
Thread-8 10 time  update oldValue : 27 , result : OK
Test counter: 36
Thread-6 10 time  update oldValue : 28 , result : EXISTS
Test counter: 43
Thread-10 10 time  update oldValue : 31 , result : EXISTS
Test counter: 52
Thread-9 10 time  update oldValue : 31 , result : OK
Test counter: 60
Thread-7 10 time  update oldValue : 35 , result : OK
Test counter: 65

3. 分析

我們可以看到，未成功的次數最終為65，資料值最終為35，兩者的和剛好是100，正好符合我們的實驗結果預期。