Getting an EhCache instance with Spring... intelligently

Question

I need to get a specific EhCache instance by name and I'd prefer to autowire if possible. Given the following automatically configured controller, how can I autowire in the cache instance I'm looking for?

@Controller 
public class MyUniqueService {
    ...
}

---

<beans ...>
    <ctx:component-scan base-package="my.controllers"/>
    <mvc:annotation-driven />
</beans>

How do I configure EhCache in my application context? I don't see any log messages from EhCache about it loading the ehcache.xml file in my /WEB-INF/ directory. How do I make it load it?

How can I integrate EhCache with my Spring application to have it load the ehcache.xml file from my /WEB-INF/ directory and autowire a cache by a given name into my MyUniqueService controller?

Answer 1

First you need to create a Ehcache CacheManager singleton in you app context like this:

<bean id="myEhCacheManager" class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean">
    <property name="configLocation" value="classpath:my-ehcache.xml"/>
</bean>

Here configLocation is set to load from classpath or use value="/WEB-INF/my-ehcache.xml".

In your controller simply inject the CacheManager instance:

@Controller 
public class MyUniqueService {

    @Resource(name="myEhCacheManager")
    private CacheManager cacheManager;

    ...
}

---

Alternatively, if you'd like to go the "entirely autowired" route, do:

<bean class="org.springframework.cache.ehcache.EhCacheCacheManager">
    <property name="cacheManager">
        <bean class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean">
            <property name="configLocation" value="/WEB-INF/ehcache.xml"/>
        </bean>
    </property>
</bean>

Setup your class like so:

@Controller
public class MyUniqueService { 

    @Autowired
    private org.springframework.cache.CacheManager cacheManager;

    public org.springframework.cache.Cache getUniqueObjectCache() {
        return cacheManager.getCache("uniqueObjectCache");
    }
}

uniqueObjectCache corresponds to this cache instance in your ehcache.xml cache definition:

<cache name="uniqueObjectCache"
       maxElementsInMemory="10000"
       eternal="false"
       timeToIdleSeconds="300"
       timeToLiveSeconds="600"
       memoryStoreEvictionPolicy="LRU"
       transactionalMode="off"/>

There isn't a way to inject an actual cache instance, but as shown above, you can inject a cache manager and use it to get the cache you're interested in.