How to create CaffeineCache object using Java?

Question

I am trying to use Caffeine cache. How to create the object for the Caffeine cache using Java? I am not using any Spring for now in my project.

Answer 1

Based on Caffeine's official repository and wiki, Caffeine is a high performance Java 8 based caching library providing a near optimal hit rate. And it is inspired by Google Guava.

Because Caffeine is an in-memory cache it is quite simple to instantiate a cache object.

For example:

LoadingCache<Key, Graph> graphs = Caffeine.newBuilder()
    .maximumSize(10_000)
    .expireAfterWrite(5, TimeUnit.MINUTES)
    .refreshAfterWrite(1, TimeUnit.MINUTES)
    .build(key -> createExpensiveGraph(key));

1. Lookup an entry, or null if not found:

   Graph graph = graphs.getIfPresent(key);
   

2. Lookup and compute an entry if absent, or null if not computable:

   graph = graphs.get(key, k -> createExpensiveGraph(key));

   Note: createExpensiveGraph(key) may be a DB getter or an actual computed graph.

3. Insert or update an entry:

   graphs.put(key, graph);
   

4. Remove an entry:

   graphs.invalidate(key);
   

EDIT: Thanks to @BenManes's suggestion, I'm adding the dependency:

Edit your pom.xml and add:

<dependency>
    <groupId>com.github.ben-manes.caffeine</groupId>
    <artifactId>caffeine</artifactId>
    <version>1.0.0</version>
</dependency>