MemcachedClient and timeout

[Massimo Marazza]

Hello,

I'm new to this list, I've been looking for a solution to my problem
but I didn't found it, so please help me, any guidance would be very very
appreciated.
I'm using a java tag lib that in the doStartTag() method search a value
for a given key in the memcached sever. I'm using 
net.spy.memcached.MemcachedClient
and in the doStartTag() code I do something similar this:

 // hostcache = myserver1:11211
 MemcachedClient memcachedClient = new 
MemcachedClient(AddrUtil.getAddresses(hostcache));
 ....
 Object myObj = null;
 Future<Object> f = memcachedClient.asyncGet(mykey.toString());

 try {
   int timeOut = 100;
   myObj = f.get(timeOut, TimeUnit.MILLISECONDS);
   if (myObj == null){
     //try to get the resource without using memcached
     ...
   }else{
     System.out.println("content cached!!!");
   }
 }catch(TimeoutException e) {
   f.cancel(true);
   //try to get the resource without using memcached
   ...
 }

 Suppose I have to use this tag library in a web page X times, because
 that page references X articles that have to be cached. I'm using 
Tomcat 5.5
 java version "1.5.0_06".
 Suppose that the memcache server is down. During my tests, I noticed
 that when I get the page, the thread try to connect the server and the 
time
 to get page is T1 + <timeOut>*X, where T1 is the time to get other 
components,
 timeOut is the Timeout setting in the Future.get method and X is the 
number
 of taglib calls.
 1. Do I always have to wait for Timeout if the server is down?
    Is there a way to reduce this load time? Can the code realize
    the the server is down?
 2. Instead of creating a new MemcachedClient in the taglib class

    MemcachedClient memcachedClient = new 
MemcachedClient(AddrUtil.getAddresses(hostcache));
   
    I tried to get an istance of class MemcachedClient
    
    memcachedClient = (MemcachedClient) 
pageContext.getServletContext().getAttribute("memcachedClient");
    
    created at context startup in this way:
   
   public class ContextInitializer implements ServletContextListener {
      
      public void contextInitialized(ServletContextEvent event) {
         ServletContext context = event.getServletContext();
         String hostcache = context.getInitParameter("hostmemcached");

         try {
             context.setAttribute("memcachedClient", new 
MemcachedClient(AddrUtil.getAddresses(hostcache)));

         } catch (Throwable e) {
           System.out.println("MemcachedClient not Initialized");
           e.printStackTrace();
         }
     }
     
     public void contextDestroyed(ServletContextEvent event) {}
   }
     
     If the memcached server is down, the context doesn't start and 
I've noticed
     in the catalina log the tread trying to connect to memcached 
server. If the server is up
     I don't have problems.
     Is it correct to create a new MemcachedClient in the taglib? Could 
I have a java.lang.OutOfMemory Exception
     using a lot of taglib to cache contents? Why the context doesn't
     start when I try to create a single istance of MemcachedClient in 
ContextInitializer?


Thank you very much for your help!

Massimo