Package org.glassfish.hk2.utilities.cache

Class LRUCache<K,​V>

  • Type Parameters:
    K - The key type for this cache
    V - The value type for this cache
    Direct Known Subclasses:
    LRUCacheCheapRead
    public abstract class LRUCache<K,​V>
extends java.lang.Object
    A cache that contains a certain number of entries, and whose oldest accessed entries are removed when removal is necessary.

    • Constructor Summary

      Constructors 
      Constructor Description
      LRUCache()  

    • Method Summary

      All Methods Static Methods Instance Methods Abstract Methods Concrete Methods 
      Modifier and Type Method Description
      static <K,​V>
      LRUCache<K,​V>      		 createCache​(int maxCacheSize)
      Creates a cache with the given maximum cache size
      abstract V get​(K key)
      Returns the value associated with the given key.
      abstract int getMaxCacheSize()
      Returns the maximum number of entries that will be stored in this cache
      abstract CacheEntry put​(K key, V value)
      Adds the given key and value pair into the cache
      abstract void releaseCache()
      Clears all entries in the cache, for use when a known event makes the cache incorrect
      abstract void releaseMatching​(CacheKeyFilter<K> filter)
      This method will remove all cache entries for which this filter matches

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Constructor Detail

      • LRUCache

        public LRUCache()

    • Method Detail

      • createCache

        public static <K,​V> LRUCache<K,​V> createCache​(int maxCacheSize)
        Creates a cache with the given maximum cache size
        Parameters:
        maxCacheSize - The maximum number of entries in the cache, must be greater than 2
        Returns:
        An LRUCache that can be used to quickly retrieve objects

      • get

        public abstract V get​(K key)
        Returns the value associated with the given key. If there is no value, returns null
        Parameters:
        key - Must be a non-null key, appropriate for use as the key to a hash map
        Returns:
        The value associated with the key, or null if there is no such value

      • put

        public abstract CacheEntry put​(K key,
                               V value)
        Adds the given key and value pair into the cache
        Parameters:
        key - Must be a non-null key, appropriate for use as the key to a hash map
        value - Must be a non-null value
        Returns:
        A cache entry that can be used to remove this entry from the cache. Will not return null

      • releaseCache

        public abstract void releaseCache()
        Clears all entries in the cache, for use when a known event makes the cache incorrect

      • getMaxCacheSize

        public abstract int getMaxCacheSize()
        Returns the maximum number of entries that will be stored in this cache
        Returns:
        The maximum number of entries that will be stored in this cache

      • releaseMatching

        public abstract void releaseMatching​(CacheKeyFilter<K> filter)
        This method will remove all cache entries for which this filter matches
        Parameters:
        filter - Entries in the cache that match this filter will be removed from the cache. If filter is null nothing will be removed from the cache