com.google.common.cache

Class ForwardingCache<K,V>

    • Constructor Summary

      Constructors

      Modifier Constructor and Description
      protected ForwardingCache()
      Constructor for use by subclasses.

    • Method Summary

      Modifier and Type Method and Description
      ConcurrentMap<K,V> asMap()
      Returns a view of the entries stored in this cache as a thread-safe map.
      void cleanUp()
      Performs any pending maintenance operations needed by the cache.
      protected abstract Cache<K,V> delegate()
      Returns the backing delegate instance that methods are forwarded to.
      V get(K key, Callable<? extends V> valueLoader)
      Returns the value associated with key in this cache, obtaining that value from valueLoader if necessary.
      ImmutableMap<K,V> getAllPresent(Iterable<?> keys)
      Returns a map of the values associated with keys in this cache.
      V getIfPresent(Object key)
      Returns the value associated with key in this cache, or null if there is no cached value for key.
      void invalidate(Object key)
      Discards any cached value for key key.
      void invalidateAll()
      Discards all entries in the cache.
      void invalidateAll(Iterable<?> keys)
      Discards any cached values for keys keys.
      void put(K key, V value)
      Associates value with key in this cache.
      void putAll(Map<? extends K,? extends V> m)
      Copies all of the mappings from the specified map to the cache.
      long size()
      Returns the approximate number of entries in this cache.
      CacheStats stats()
      Returns a current snapshot of this cache's cumulative statistics.

    • Constructor Detail

      • ForwardingCache

        protected ForwardingCache()
        Constructor for use by subclasses.

    • Method Detail

      • delegate

        protected abstract Cache<K,V> delegate()
        Description copied from class: ForwardingObject
        Returns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such as ForwardingSet.delegate(). Concrete subclasses override this method to supply the instance being decorated.

      • getIfPresent

        public V getIfPresent(Object key)
        Description copied from interface: Cache
        Returns the value associated with key in this cache, or null if there is no cached value for key.
        Specified by:
        getIfPresent in interface  Cache<K,V>
        Since:
        11.0

      • get

        public V get(K key,
             Callable<? extends V> valueLoader)
      throws ExecutionException
        Description copied from interface: Cache
        Returns the value associated with key in this cache, obtaining that value from valueLoader if necessary. No observable state associated with this cache is modified until loading completes. This method provides a simple substitute for the conventional "if cached, return; otherwise create, cache and return" pattern.

        Warning: as with CacheLoader.load(K), valueLoader must not return null; it may either return a non-null value or throw an exception.

        Specified by:
        get in interface  Cache<K,V>
        Throws:
        ExecutionException - if a checked exception was thrown while loading the value
        Since:
        11.0

      • getAllPresent

        public ImmutableMap<K,V> getAllPresent(Iterable<?> keys)
        Description copied from interface: Cache
        Returns a map of the values associated with keys in this cache. The returned map will only contain entries which are already present in the cache.
        Specified by:
        getAllPresent in interface  Cache<K,V>
        Since:
        11.0

      • put

        public void put(K key,
                V value)
        Description copied from interface: Cache
        Associates value with key in this cache. If the cache previously contained a value associated with key, the old value is replaced by value.

        Prefer Cache.get(Object, Callable) when using the conventional "if cached, return; otherwise create, cache and return" pattern.

        Specified by:
        put in interface  Cache<K,V>
        Since:
        11.0

      • putAll

        public void putAll(Map<? extends K,? extends V> m)
        Description copied from interface: Cache
        Copies all of the mappings from the specified map to the cache. The effect of this call is equivalent to that of calling put(k, v) on this map once for each mapping from key k to value v in the specified map. The behavior of this operation is undefined if the specified map is modified while the operation is in progress.
        Specified by:
        putAll in interface  Cache<K,V>
        Since:
        12.0

      • invalidate

        public void invalidate(Object key)
        Description copied from interface: Cache
        Discards any cached value for key key.

      • invalidateAll

        public void invalidateAll(Iterable<?> keys)
        Description copied from interface: Cache
        Discards any cached values for keys keys.
        Specified by:
        invalidateAll in interface  Cache<K,V>
        Since:
        11.0

      • invalidateAll

        public void invalidateAll()
        Description copied from interface: Cache
        Discards all entries in the cache.

      • size

        public long size()
        Description copied from interface: Cache
        Returns the approximate number of entries in this cache.

      • stats

        public CacheStats stats()
        Description copied from interface: Cache
        Returns a current snapshot of this cache's cumulative statistics. All stats are initialized to zero, and are monotonically increasing over the lifetime of the cache.

      • asMap

        public ConcurrentMap<K,V> asMap()
        Description copied from interface: Cache
        Returns a view of the entries stored in this cache as a thread-safe map. Modifications made to the map directly affect the cache.

        Iterators from the returned map are at least weakly consistent: they are safe for concurrent use, but if the cache is modified (including by eviction) after the iterator is created, it is undefined which of the changes (if any) will be reflected in that iterator.

      • cleanUp

        public void cleanUp()
        Description copied from interface: Cache
        Performs any pending maintenance operations needed by the cache. Exactly which activities are performed -- if any -- is implementation-dependent.