Lightweight Java Object cache API [closed]

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.

Answer 2

I really like the MapMaker that comes with Google Guava (API)

The JavaDoc has a pretty neat example that demonstrates both its ease of use and its power:

ConcurrentMap<Key, Graph> graphs = new MapMaker()
   .concurrencyLevel(32)
   .softKeys()
   .weakValues()
   .expiration(30, TimeUnit.MINUTES)
   .makeComputingMap(
       new Function<Key, Graph>() {
         public Graph apply(Key key) {
           return createExpensiveGraph(key);
         }
       });

Furthermore, release 10.0 of Guava introduced the much more extensive com.google.common.cache package (there's a nice wiki entry on how to use them).

Answer 3

JCS is tried and true. Even though it is light as far as caching mechanisms go, you might dig into the actual code and mimic what they do with HashMap under the covers to exactly what you need and no more. You seem to have a pretty good idea of what you are looking for.

Answer 4

Guava's MapMaker has been replaced by their CacheBuilder class.

Answer 5

You can also check out my little cache library called KittyCache at:

https://github.com/treeder/kitty-cache

There are some performance benchmarks vs ehcache.

It's used in the SimpleJPA project as a second level cache.

Answer 6

memcached has client for Java. http://www.danga.com/memcached/ Requires separate process to be a caching server, but powerful thing.