集群环境中利用Memcached CAS原子操作计数

package org.pile.memcached;

import java.io.IOException;
import java.util.Random;
import java.util.concurrent.atomic.AtomicInteger;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.pile.util.LogWriter;

import net.spy.memcached.CASValue;

public class CASLockServlet extends HttpServlet {
//private static final int[] LEVEL = {10,50,200,500,1000,5000,10000,20000};
private static final String CACHE_KEY = "CASLOCK";
private volatile static AtomicInteger visitTimes = new AtomicInteger();
//private Random		  random     = new Random();

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String responseBody = null;
if(null != request.getParameter("reset")){
visitTimes = new AtomicInteger();
MemCache.setCache(CACHE_KEY, 0, 0);
LogWriter.printLog("Reset servlet status.");
ResponseBuilder.buildResponse("Reset ok!", response);
return;
}
if(null != request.getParameter("print")){
responseBody = "Servlet Object value ::" + visitTimes.intValue();
responseBody += " Memcached Object value ::" + MemCache.getCache(CACHE_KEY).toString();
LogWriter.printLog("Print servlet status.");
ResponseBuilder.buildResponse(responseBody, response);
return;
}
int step  = 1;
visitTimes.addAndGet(step);
LogWriter.printLog("Update local value::" + visitTimes.intValue());
while(true){
LogWriter.printLog("Begin to get CASValue::" + visitTimes.intValue());
CASValue<Object> casValue = MemCache.getCasId(CACHE_KEY);
LogWriter.printLog("End to get CASValue::" + casValue.getValue().toString());
int cachTimes = Integer.parseInt(casValue.getValue().toString()) + step;
if(MemCache.casCache(CACHE_KEY, casValue.getCas(), String.valueOf(cachTimes))){
LogWriter.printLog("Success to CAS Cache::" + cachTimes);
break;
}
else{
LogWriter.printLog("Fail to CAS Cache::" + cachTimes);
try{
Thread.sleep(200);
}
catch(Exception exp){
exp.printStackTrace();
}
}
}
}
}