Simple Spring Memcached [ Memcached + Spring Caching ]

Introduction

Memcached is undoubtedly one of the most popular distributed caching system used across applications. Through his post I will try to make you understand on how to integrate memcache with a Spring enabled applications. Since Spring directly supports only Ehcache therefore we will use google's SSM (Simple Spring Memcache ) to use spring caching abstraction.

Getting started

1. Dependencies - For downloading SSM dependencies add following to your POM. 

 
  com.google.code.simple-spring-memcached
  spring-cache
  3.2.0
 
 
  com.google.code.simple-spring-memcached
  spymemcached-provider
  3.2.0
 
 

2. Enable Caching – To enable caching in your spring application add following to your spring memcached.xml.

<cache:annotation-driven/>

3. Configure Spring to enable Memcached based caching  – Add following to your application memcached.xml.

 
 
    
      
        
          
          
          
          
          
        
         
           // "applicationData1" is 1st cache Name for your code
          
          
          
          
        
         
           // "applicationData2" is 2nd cache Name for your code
          
          
          
          
        
        
    
  

 
  
  
   
  
  
   
    
   
  
  
   
    
   
      
      
  
  
   
     
 

  
    
  

  
    
  
 

** Note: You have to keep on adding "applicationData1", "applicationData2" ......."applicationData.....N" if you have N number of cache name for your application. 

Limitation: You are having common key for two different value as mentioned below.

@Cacheable(value = "applicationData1", key = #EmployeeId")

@Cacheable(value = "applicationData2", key = #EmployeeId")

In above scenario two  same key are trying to put some value therefore one key will overwrite the other key value and will lead to data corruption. To avoid this we have to make our key unique. This can be achieved by adding a string in-front of the key as done below. 

@Cacheable(value = "applicationData1", key = "'applicationData1'+#EmployeeId")

@Cacheable(value = "applicationData2", key = "'applicationData2'+#EmployeeId")

If you have no constraint about overwriting cache value then there is no need for making your key unique and everything can be put in single memcache. 

As stated earlier in my different post "phpMemCachedAdmin" is a great tool to Monitor And Debug Memcached Server [ http://kulshresht-gautam.blogspot.in/2013/08/how-to-monitor-and-debug-memcached.html ]. In the snap below you can see that the key and it's corresponding size. Expiration time for these keys are infinite which is clearly visible from snapshot below.

How to install memcache : I had explained it here: http://kulshresht-gautam.blogspot.in/2013/07/memcached-installation.html


References:
https://code.google.com/p/simple-spring-memcached/wiki/Getting_Started
https://code.google.com/p/simple-spring-memcached/wiki/UserGuide#Cache_zone