Cache extensions are a general-purpose mechanism to allow generic extensions to a cache. Cache extensions are tied into the cache lifecycle. For that reason, this interface has the lifecycle methods.

Cache extensions are created using the CacheExtensionFactory, which has a createCacheCacheExtension() method that takes as a parameter a Cache and properties. It can thus call back into any public method on Cache, including, of course, the load methods. Cache extensions are suitable for timing services, where you want to create a timer to perform cache operations. (Another way of adding Cache behavior is to decorate a cache. For an example of, Blocking and Self Populating Caches.)

Because a CacheExtension holds a reference to a Cache, the CacheExtension can do things such as registering a CacheEventListener or even a CacheManagerEventListener, all from within a CacheExtension, creating more opportunities for customization.