Spring Cache

A cache itself may be imagined as a key-value map. For a basic Cache we need:

@EnableCaching tag in @Configuration class
Declare a CacheManager Bean
Tag the method to cache w. @Cacheable
Create a method with @CacheEvict

We may declare +1 cache(s) at the cache manager and select the one we want to use in the method we tag. As key for the cache we may use any conjunction of the parameters given to the method, or if this is a class, any of it’s accessible variables. The cache will only be triggered when the exact key is given again. Then the method won’t be executed and the value will be directly given from the cache. If the parameters don’t match any key, the method will be executed as normal and then the value will be saved into the cache to be returned the next time.

Caution with logs in big apps as they need to be written accordingly.
The hard part is not knowing when to cache something, but to know when to Evict the cache.

Default Cache

Spring provides Cache and CacheManager as main abstractions for the caching logic. They do not provide the actual storage to store data. For that we have some options out of the box on the JDK such as SimpleCacheManager. It’s based on ConcurrentMap and it’s useful when we need a really basic Cache, but it does not support the eviction or persistence of the Cache.

EHCache

The entities to save, have to implement Serializable interface. If we don’t do that, it’ll throw a NotSerializableException.
The config for the several caches is specified in ehcache.xml

Infinispan

It’s an in-memory, highly concurrent Cache. It has built-in Eviction. It may be deployed in local mode but it’s a best choice for its cluster mode (distributed or replicated).

References

https://spring.io/guides/gs/caching/
https://www.baeldung.com/spring-cache-tutorial
http://websystique.com/spring/spring-4-cache-tutorial-with-ehcache/
https://blog.infinispan.org/2010/02/infinispan-as-local-cache.html
http://infinispan.org/docs/stable/user_guide/user_guide.html#clustering