com.google.common.cache
@Beta @GwtCompatible public abstract class AbstractCache<K,V> extends java.lang.Object implements Cache<K,V>
Cache interface to minimize the
effort required to implement this interface.
To implement a cache, the programmer needs only to extend this class and provide an
implementation for the Cache.getIfPresent(K) method. getAllPresent(java.lang.Iterable) is implemented in
terms of getIfPresent; invalidateAll(Iterable) is implemented in terms of
invalidate(java.lang.Object). The method cleanUp() is a no-op. All other methods throw an
UnsupportedOperationException.
| Modifier and Type | Class and Description |
|---|---|
static class |
AbstractCache.SimpleStatsCounter
A thread-safe
AbstractCache.StatsCounter implementation for use by Cache implementors. |
static interface |
AbstractCache.StatsCounter
Accumulates statistics during the operation of a
Cache for presentation by Cache.stats(). |
| Modifier | Constructor and Description |
|---|---|
protected |
AbstractCache()
Constructor for use by subclasses.
|
| Modifier and Type | Method and Description |
|---|---|
V |
apply(K key)
Deprecated.
|
java.util.concurrent.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,
java.util.concurrent.Callable<? extends V> valueLoader)
Returns the value associated with
key in this cache, obtaining that value from
valueLoader if necessary. |
ImmutableMap<K,V> |
getAllPresent(java.lang.Iterable<? extends K> keys)
Returns a map of the values associated with
keys in this cache. |
V |
getUnchecked(K key)
Deprecated.
|
void |
invalidate(java.lang.Object key)
Discards any cached value for key
key. |
void |
invalidateAll()
Discards all entries in the cache.
|
void |
invalidateAll(java.lang.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.
|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitget, getIfPresentpublic V get(K key, java.util.concurrent.Callable<? extends V> valueLoader) throws java.util.concurrent.ExecutionException
Cachekey 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.
public ImmutableMap<K,V> getAllPresent(java.lang.Iterable<? extends K> keys)
Cachekeys in this cache. The returned map will
only contain entries which are already present in the cache.getAllPresent in interface Cache<K,V>public void put(K key, V value)
Cachevalue 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.
public void cleanUp()
Cachepublic long size()
Cachepublic void invalidate(java.lang.Object key)
Cachekey.invalidate in interface Cache<K,V>public void invalidateAll(java.lang.Iterable<?> keys)
Cachekeys.invalidateAll in interface Cache<K,V>public void invalidateAll()
CacheinvalidateAll in interface Cache<K,V>public CacheStats stats()
Cachepublic java.util.concurrent.ConcurrentMap<K,V> asMap()
Cache@Deprecated public V getUnchecked(K key)
Cachekey in this cache, first loading that value if
necessary. No observable state associated with this cache is modified until computation
completes. Unlike Cache.get(K, java.util.concurrent.Callable), 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.
getUnchecked in interface Cache<K,V>@Deprecated public V apply(K key)
CacheFunction interface; use Cache.get(K, java.util.concurrent.Callable) or
Cache.getUnchecked(K) instead.