Question

Question

I’m looking for a Java in-memory object caching API. Any recommendations? What solutions have you used in the past?

Current

Right now, I’m just using a Map:

Map cache = new HashMap<String, Object>(); cache.put('key', value); 

Requirements

I need to extend the cache to include basic features like:

• Max size
• Time to live

However, I don’t need more sophisticated features like:

• Access from multiple processes (caching server)
• Persistence (to disk)

Suggestions

In-Memory caching:

• Guava CacheBuilder – active development. See this presentation.
• LRUMap – Config via API. No TTL. Not purpose built for caching.
• whirlycache – XML config. Mailing list. Last updated 2006.
• cache4j – XML config. Documentation in Russian. Last updated 2006.

Enterprise caching:

• JCS – Properties config. Extensive documentation.
• Ehcache – XML config. Extensive documentation. By far the most popular according to Google hits.

Answer 1

EHCache is very nice. You can create an in memory cache. Check out their code samples for an example of creating an in memory cache. You can specify a max size, and a time to live.

EHCache does offer some advanced features, but if your not interested in using them – don’t. But it’s nice to know they are there if your requirements ever change.

Here is an in memory cache. Created in code, with no configuration files.

CacheManager cacheManager = CacheManager.getInstance(); int oneDay = 24 * 60 * 60; Cache memoryOnlyCache = new Cache('name', 200, false, false, oneDay, oneDay); cacheManager.addCache(memoryOnlyCache); 

Creates a cache that will hold 200 elements, and has a ttl of 24 hours.