Factory and FactoryBuilder

The javax.cache.configuration.Factory implementations are used to configure features like CacheEntryListener, ExpirePolicy and CacheLoaders or CacheWriters. These factory implementations are required to distribute the different features to nodes in a cluster environment like Hazelcast. Therefore, these factory implementations have to be serializable.

Factory implementations are easy to do: they follow the default Provider- or Factory-Pattern. The sample class UserCacheEntryListenerFactory shown below implements a custom JCache Factory.

public class UserCacheEntryListenerFactory
    implements Factory<CacheEntryListener<Integer, User>> {

  public CacheEntryListener<Integer, User> create() {
    // Just create a new listener instance
    return new UserCacheEntryListener();

To simplify the process for the users, JCache API offers a set of helper methods collected in javax.cache. configuration.FactoryBuilder. In the above configuration example, FactoryBuilder::factoryOf is used to create a singleton factory for the given instance.