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com.google.common.cache
Interface Cache<K,V>
- All Superinterfaces:
- Function<K,V>
- All Known Subinterfaces:
- LoadingCache<K,V>
- All Known Implementing Classes:
- AbstractCache, AbstractLoadingCache, ForwardingCache, ForwardingCache.SimpleForwardingCache, ForwardingLoadingCache, ForwardingLoadingCache.SimpleForwardingLoadingCache
@Beta
@GwtCompatible
public interface Cache<K,V>
- extends Function<K,V>
A semi-persistent mapping from keys to values. Cache entries are manually added using
#get(K, Callable)
or #put(K, V)
, and are stored in the cache until either
evicted or manually invalidated.
Note: in release 12.0, all methods moved from Cache
to LoadingCache
will be deleted from Cache
. As part of this transition Cache
will no longer
extend Function
.
Implementations of this interface are expected to be thread-safe, and can be safely accessed by multiple concurrent threads.
All methods other than getIfPresent(K)
are optional.
- Since:
- 10.0
- Author:
- Charles Fry
Method Summary | |
---|---|
V |
apply(K key)
Deprecated. This method has been split out into the LoadingCache interface, and will be
removed from Cache in Guava release 12.0. Note that
CacheBuilder.build(CacheLoader) now returns a LoadingCache , so this deprecation
(migration) can be dealt with by simply changing the type of references to the results of
CacheBuilder.build(CacheLoader) . |
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. |
V |
get(K key)
Deprecated. This method has been split out into the LoadingCache interface, and will be
removed from Cache in Guava release 12.0. Note that
CacheBuilder.build(CacheLoader) now returns a LoadingCache , so this deprecation
(migration) can be dealt with by simply changing the type of references to the results of
CacheBuilder.build(CacheLoader) . |
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<? extends K> keys)
Returns a map of the values associated with keys in this cache. |
V |
getIfPresent(K key)
Returns the value associated with key in this cache, or null if there is no
cached value for key . |
V |
getUnchecked(K key)
Deprecated. This method has been split out into the LoadingCache interface, and will be
removed from Cache in Guava release 12.0. Note that
CacheBuilder.build(CacheLoader) now returns a LoadingCache , so this deprecation
(migration) can be dealt with by simply changing the type of references to the results of
CacheBuilder.build(CacheLoader) . |
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. |
long |
size()
Returns the approximate number of entries in this cache. |
CacheStats |
stats()
Returns a current snapshot of this cache's cumulative statistics. |
Methods inherited from interface com.google.common.base.Function |
---|
equals |
Method Detail |
---|
getIfPresent
@Nullable V getIfPresent(K key)
- Returns the value associated with
key
in this cache, ornull
if there is no cached value forkey
.- Since:
- 11.0
get
V get(K key, Callable<? extends V> valueLoader) throws ExecutionException
- Returns the value associated with
key
in this cache, obtaining that value fromvalueLoader
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 returnnull
; it may either return a non-null value or throw an exception.- Throws:
ExecutionException
- if a checked exception was thrown while loading the valueUncheckedExecutionException
- if an unchecked exception was thrown while loading the valueExecutionError
- if an error was thrown while loading the value- Since:
- 11.0
getAllPresent
ImmutableMap<K,V> getAllPresent(Iterable<? extends K> keys)
- 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.- Since:
- 11.0
put
void put(K key, V value)
- Associates
value
withkey
in this cache. If the cache previously contained a value associated withkey
, the old value is replaced byvalue
.Prefer
get(Object, Callable)
when using the conventional "if cached, return; otherwise create, cache and return" pattern.- Since:
- 11.0
invalidate
void invalidate(Object key)
- Discards any cached value for key
key
.
invalidateAll
void invalidateAll(Iterable<?> keys)
- Discards any cached values for keys
keys
.- Since:
- 11.0
invalidateAll
void invalidateAll()
- Discards all entries in the cache.
size
long size()
- Returns the approximate number of entries in this cache.
stats
CacheStats stats()
- 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
ConcurrentMap<K,V> asMap()
- Returns a view of the entries stored in this cache as a thread-safe map. Modifications made to
the map directly affect the cache.
cleanUp
void cleanUp()
- Performs any pending maintenance operations needed by the cache. Exactly which activities are
performed -- if any -- is implementation-dependent.
get
@Deprecated V get(K key) throws ExecutionException
- Deprecated. This method has been split out into the
LoadingCache
interface, and will be removed fromCache
in Guava release 12.0. Note thatCacheBuilder.build(CacheLoader)
now returns aLoadingCache
, so this deprecation (migration) can be dealt with by simply changing the type of references to the results ofCacheBuilder.build(CacheLoader)
.- Returns the value associated with
key
in this cache, first loading that value if necessary. No observable state associated with this cache is modified until loading completes.- Throws:
ExecutionException
- if a checked exception was thrown while loading the valueUncheckedExecutionException
- if an unchecked exception was thrown while loading the valueExecutionError
- if an error was thrown while loading the value
- Returns the value associated with
getUnchecked
@Deprecated V getUnchecked(K key)
- Deprecated. This method has been split out into the
LoadingCache
interface, and will be removed fromCache
in Guava release 12.0. Note thatCacheBuilder.build(CacheLoader)
now returns aLoadingCache
, so this deprecation (migration) can be dealt with by simply changing the type of references to the results ofCacheBuilder.build(CacheLoader)
.- Returns the value associated with
key
in this cache, first loading that value if necessary. No observable state associated with this cache is modified until computation completes. Unlikeget(K, java.util.concurrent.Callable extends V>)
, this method does not throw a checked exception, and thus should only be used in situations where checked exceptions are not thrown by the cache loader.Warning: this method silently converts checked exceptions to unchecked exceptions, and should not be used with cache loaders which throw checked exceptions.
- Throws:
UncheckedExecutionException
- if an exception was thrown while loading the value, regardless of whether the exception was checked or uncheckedExecutionError
- if an error was thrown while loading the value
- Returns the value associated with
apply
@Deprecated V apply(K key)
- Deprecated. This method has been split out into the
LoadingCache
interface, and will be removed fromCache
in Guava release 12.0. Note thatCacheBuilder.build(CacheLoader)
now returns aLoadingCache
, so this deprecation (migration) can be dealt with by simply changing the type of references to the results ofCacheBuilder.build(CacheLoader)
.- Discouraged. Provided to satisfy the
Function
interface; useget(K, java.util.concurrent.Callable extends V>)
orgetUnchecked(K)
instead.- Throws:
UncheckedExecutionException
- if an exception was thrown while loading the value, regardless of whether the exception was checked or uncheckedExecutionError
- if an error was thrown while loading the value
- Discouraged. Provided to satisfy the
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