Interface LocalManualCache<C extends LocalCache<K,V>,K,V>
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- All Superinterfaces:
Cache<K,V>
- All Known Subinterfaces:
LocalLoadingCache<C,K,V>
- All Known Implementing Classes:
BoundedLocalCache.BoundedLocalLoadingCache,BoundedLocalCache.BoundedLocalManualCache,UnboundedLocalCache.UnboundedLocalLoadingCache,UnboundedLocalCache.UnboundedLocalManualCache
interface LocalManualCache<C extends LocalCache<K,V>,K,V> extends Cache<K,V>
This class provides a skeletal implementation of theCacheinterface to minimize the effort required to implement aLocalCache.
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Method Summary
All Methods Instance Methods Abstract Methods Default Methods Modifier and Type Method Description default java.util.concurrent.ConcurrentMap<K,V>asMap()Returns a view of the entries stored in this cache as a thread-safe map.Ccache()Returns the backingLocalCachedata store.default voidcleanUp()Performs any pending maintenance operations needed by the cache.default longestimatedSize()Returns the approximate number of entries in this cache.default Vget(K key, java.util.function.Function<? super K,? extends V> mappingFunction)Returns the value associated with thekeyin this cache, obtaining that value from themappingFunctionif necessary.default java.util.Map<K,V>getAllPresent(java.lang.Iterable<?> keys)Returns a map of the values associated with thekeysin this cache.default VgetIfPresent(java.lang.Object key)Returns the value associated with thekeyin this cache, ornullif there is no cached value for thekey.default voidinvalidate(java.lang.Object key)Discards any cached value for thekey.default voidinvalidateAll()Discards all entries in the cache.default voidinvalidateAll(java.lang.Iterable<?> keys)Discards any cached values for thekeys.default voidput(K key, V value)Associates thevaluewith thekeyin this cache.default voidputAll(java.util.Map<? extends K,? extends V> map)Copies all of the mappings from the specified map to the cache.default CacheStatsstats()Returns a current snapshot of this cache's cumulative statistics.
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Method Detail
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cache
C cache()
Returns the backingLocalCachedata store.
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estimatedSize
default long estimatedSize()
Description copied from interface:CacheReturns the approximate number of entries in this cache. The value returned is an estimate; the actual count may differ if there are concurrent insertions or removals, or if some entries are pending removal due to expiration or weak/soft reference collection. In the case of stale entries this inaccuracy can be mitigated by performing aCache.cleanUp()first.- Specified by:
estimatedSizein interfaceCache<C extends LocalCache<K,V>,K>- Returns:
- the estimated number of mappings
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cleanUp
default void cleanUp()
Description copied from interface:CachePerforms any pending maintenance operations needed by the cache. Exactly which activities are performed -- if any -- is implementation-dependent.
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getIfPresent
@Nullable default V getIfPresent(java.lang.Object key)
Description copied from interface:CacheReturns the value associated with thekeyin this cache, ornullif there is no cached value for thekey.- Specified by:
getIfPresentin interfaceCache<C extends LocalCache<K,V>,K>- Parameters:
key- the key whose associated value is to be returned- Returns:
- the value to which the specified key is mapped, or
nullif this map contains no mapping for the key
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get
default V get(K key, java.util.function.Function<? super K,? extends V> mappingFunction)
Description copied from interface:CacheReturns the value associated with thekeyin this cache, obtaining that value from themappingFunctionif necessary. This method provides a simple substitute for the conventional "if cached, return; otherwise create, cache and return" pattern.If the specified key is not already associated with a value, attempts to compute its value using the given mapping function and enters it into this cache unless
null. The entire method invocation is performed atomically, so the function is applied at most once per key. Some attempted update operations on this cache by other threads may be blocked while the computation is in progress, so the computation should be short and simple, and must not attempt to update any other mappings of this cache.Warning: as with
CacheLoader.load(K),mappingFunctionmust not attempt to update any other mappings of this cache.- Specified by:
getin interfaceCache<C extends LocalCache<K,V>,K>- Parameters:
key- the key with which the specified value is to be associatedmappingFunction- the function to compute a value- Returns:
- the current (existing or computed) value associated with the specified key, or null if the computed value is null
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getAllPresent
default java.util.Map<K,V> getAllPresent(java.lang.Iterable<?> keys)
Description copied from interface:CacheReturns a map of the values associated with thekeysin this cache. The returned map will only contain entries which are already present in the cache.- Specified by:
getAllPresentin interfaceCache<C extends LocalCache<K,V>,K>- Parameters:
keys- the keys whose associated values are to be returned- Returns:
- the unmodifiable mapping of keys to values for the specified keys found in this cache
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put
default void put(K key, V value)
Description copied from interface:CacheAssociates thevaluewith thekeyin this cache. If the cache previously contained a value associated with thekey, the old value is replaced by the newvalue.Prefer
Cache.get(Object, Function)when using the conventional "if cached, return; otherwise create, cache and return" pattern.
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putAll
default void putAll(java.util.Map<? extends K,? extends V> map)
Description copied from interface:CacheCopies all of the mappings from the specified map to the cache. The effect of this call is equivalent to that of callingput(k, v)on this map once for each mapping from keykto valuevin the specified map. The behavior of this operation is undefined if the specified map is modified while the operation is in progress.
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invalidate
default void invalidate(java.lang.Object key)
Description copied from interface:CacheDiscards any cached value for thekey. The behavior of this operation is undefined for an entry that is being loaded and is otherwise not present.- Specified by:
invalidatein interfaceCache<C extends LocalCache<K,V>,K>- Parameters:
key- the key whose mapping is to be removed from the cache
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invalidateAll
default void invalidateAll(java.lang.Iterable<?> keys)
Description copied from interface:CacheDiscards any cached values for thekeys. The behavior of this operation is undefined for an entry that is being loaded and is otherwise not present.- Specified by:
invalidateAllin interfaceCache<C extends LocalCache<K,V>,K>- Parameters:
keys- the keys whose associated values are to be removed
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invalidateAll
default void invalidateAll()
Description copied from interface:CacheDiscards all entries in the cache. The behavior of this operation is undefined for an entry that is being loaded and is otherwise not present.- Specified by:
invalidateAllin interfaceCache<C extends LocalCache<K,V>,K>
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stats
default CacheStats stats()
Description copied from interface:CacheReturns a current snapshot of this cache's cumulative statistics. All statistics are initialized to zero, and are monotonically increasing over the lifetime of the cache.Due to the performance penalty of maintaining statistics, some implementations may not record the usage history immediately or at all.
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asMap
default java.util.concurrent.ConcurrentMap<K,V> asMap()
Description copied from interface:CacheReturns 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.
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