Package org.codehaus.groovy.runtime.memoize

Class StampedCommonCache<K,V>

java.lang.Object
org.codehaus.groovy.runtime.memoize.StampedCommonCache<K,V>
Type Parameters:
K - type of the keys
V - type of the values
All Implemented Interfaces:
Serializable, Map<K,V>, EvictableCache<K,V>, MemoizeCache<K,V>, ValueConvertable<V,Object>
@ThreadSafe public class StampedCommonCache<K,V> extends Object implements EvictableCache<K,V>, ValueConvertable<V,Object>, Serializable
Represents a simple key-value cache, which is thread safe and backed by a Map instance. StampedCommonCache has better performance than ConcurrentCommonCache, but it is not reentrant, in other words, it may cause deadlock if getAndPut(Object, MemoizeCache.ValueProvider) or getAndPut(Object, MemoizeCache.ValueProvider, boolean) is called recursively: readlock -> upgrade to writelock -> readlock (fails to get and waits forever)
Since:
3.0.0
See Also:

  • Constructor Details

    • StampedCommonCache

      public StampedCommonCache()
      Constructs a cache with unlimited size

    • StampedCommonCache

      public StampedCommonCache(int initialCapacity, int maxSize, EvictableCache.EvictionStrategy evictionStrategy)
      Constructs a cache with limited size
      Parameters:
      initialCapacity - initial capacity of the cache
      maxSize - max size of the cache
      evictionStrategy - LRU or FIFO, see EvictableCache.EvictionStrategy

    • StampedCommonCache

      public StampedCommonCache(int initialCapacity, int maxSize)
      Constructs a LRU cache with the specified initial capacity and max size. The LRU cache is slower than LRUCache
      Parameters:
      initialCapacity - initial capacity of the LRU cache
      maxSize - max size of the LRU cache

    • StampedCommonCache

      public StampedCommonCache(int maxSize)
      Constructs a LRU cache with the default initial capacity(16)
      Parameters:
      maxSize - max size of the LRU cache
      See Also:

    • StampedCommonCache

      public StampedCommonCache(Map<K,V> map)
      Constructs a cache backed by the specified Map instance
      Parameters:
      map - the Map instance

  • Method Details

    • get

      public V get(Object key)
      Gets a value from the cache
      Specified by:
      get in interface Map<K,V>
      Specified by:
      get in interface MemoizeCache<K,V>
      Parameters:
      key - the key whose associated value is to be returned
      Returns:
      the value, or null, if it does not exist.

    • put

      public V put(K key, V value)
      Associates the specified value with the specified key in the cache.
      Specified by:
      put in interface Map<K,V>
      Specified by:
      put in interface MemoizeCache<K,V>
      Parameters:
      key - key with which the specified value is to be associated
      value - value to be associated with the specified key
      Returns:
      null, or the old value if the key associated with the specified key.

    • getAndPut

      public V getAndPut(K key, MemoizeCache.ValueProvider<? super K,? extends V> valueProvider)
      Try to get the value from cache. If not found, create the value by MemoizeCache.ValueProvider and put it into the cache, at last return the value.
      Specified by:
      getAndPut in interface MemoizeCache<K,V>
      Parameters:
      key - the key to look up
      valueProvider - provide the value if the associated value not found
      Returns:
      the cached value

    • getAndPut

      public V getAndPut(K key, MemoizeCache.ValueProvider<? super K,? extends V> valueProvider, boolean shouldCache)

    • values

      public Collection<V> values()
      Get all cached values
      Specified by:
      values in interface EvictableCache<K,V>
      Specified by:
      values in interface Map<K,V>
      Returns:
      all cached values

    • entrySet

      public Set<Map.Entry<K,V>> entrySet()
      Specified by:
      entrySet in interface Map<K,V>

    • keys

      public Set<K> keys()
      Get all keys associated to cached values
      Specified by:
      keys in interface EvictableCache<K,V>
      Returns:
      all keys

    • containsKey

      public boolean containsKey(Object key)
      Determines if the cache contains an entry for the specified key.
      Specified by:
      containsKey in interface EvictableCache<K,V>
      Specified by:
      containsKey in interface Map<K,V>
      Parameters:
      key - key whose presence in this cache is to be tested.
      Returns:
      true if the cache contains a mapping for the specified key

    • containsValue

      public boolean containsValue(Object value)
      Specified by:
      containsValue in interface Map<K,V>

    • size

      public int size()
      Get the size of the cache
      Specified by:
      size in interface EvictableCache<K,V>
      Specified by:
      size in interface Map<K,V>
      Returns:
      the size of the cache

    • isEmpty

      public boolean isEmpty()
      Specified by:
      isEmpty in interface Map<K,V>

    • remove

      public V remove(Object key)
      Remove the cached value by the key
      Specified by:
      remove in interface EvictableCache<K,V>
      Specified by:
      remove in interface Map<K,V>
      Parameters:
      key - of the cached value
      Returns:
      returns the removed value

    • putAll

      public void putAll(Map<? extends K,? extends V> m)
      Specified by:
      putAll in interface Map<K,V>

    • keySet

      public Set<K> keySet()
      Specified by:
      keySet in interface Map<K,V>

    • clearAll

      public Map<K,V> clearAll()
      Clear the cache
      Specified by:
      clearAll in interface EvictableCache<K,V>
      Returns:
      returns the content of the cleared map

    • cleanUpNullReferences

      public void cleanUpNullReferences()
      Invoked when some of the held SoftReferences have been evicted by the garbage collector and so should be removed from the cache. The implementation must ensure that concurrent invocations of all methods on the cache may occur from other threads and thus should protect any shared resources.
      Specified by:
      cleanUpNullReferences in interface MemoizeCache<K,V>

    • convertValue

      public Object convertValue(V value)
      convert the original value to the target value
      Specified by:
      convertValue in interface ValueConvertable<K,V>
      Parameters:
      value - the original value
      Returns:
      the converted value