001    /*
002     @license.text@ 
003     */
004    package biz.hammurapi.cache;
005    
006    import java.util.Set;
007    
008    
009    public interface Producer {
010            Entry get(Object key);
011            
012            /**
013             * Callback method for key removal.
014             * @param cache
015             */
016            void addCache(Cache cache);
017            
018            /**
019             * @return all keys, null or empty collection if entire key set is not known
020             */
021            Set keySet();
022    }