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AbstractLoadingCache (Guava: Google Core Libraries for Java 11.0.1 API)























  
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com.google.common.cache


Class AbstractLoadingCache<K,V>
java.lang.Object
  com.google.common.cache.AbstractCache<K,V>
      com.google.common.cache.AbstractLoadingCache<K,V>


All Implemented Interfaces: 
Function<K,V>, Cache<K,V>, LoadingCache<K,V>



@Beta
public abstract class AbstractLoadingCache<K,V>extends AbstractCache<K,V>
implements LoadingCache<K,V>




This class provides a skeletal implementation of the 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 AbstractCache.get(K, java.util.concurrent.Callable) and Cache.getIfPresent(K) methods. getUnchecked(K),
 #get(K, Callable), and getAll(java.lang.Iterable) are implemented in terms of get;
 AbstractCache.getAllPresent(java.lang.Iterable) is implemented in terms of get; AbstractCache.invalidateAll(Iterable)
 is implemented in terms of AbstractCache.invalidate(java.lang.Object). The method AbstractCache.cleanUp() is a no-op. All other
 methods throw an UnsupportedOperationException.




Since:
  11.0
Author:
  Charles Fry










Nested Class Summary


 


Nested classes/interfaces inherited from class com.google.common.cache.AbstractCache


AbstractCache.SimpleStatsCounter, AbstractCache.StatsCounter


 







Constructor Summary



protected 
AbstractLoadingCache()



          Constructor for use by subclasses.


 






Method Summary



 V
apply(K key)



          Discouraged.



 ImmutableMap<K,V>
getAll(Iterable<? extends K> keys)



          Returns a map of the values associated with keys, creating or retrieving those values
 if necessary.



 V
getUnchecked(K key)



          Returns the value associated with key in this cache, first loading that value if
 necessary.



 void
refresh(K key)



          Loads a new value for key key, possibly asynchronously.


 


Methods inherited from class com.google.common.cache.AbstractCache


asMap, cleanUp, get, getAllPresent, invalidate, invalidateAll, invalidateAll, put, size, stats


 


Methods inherited from class java.lang.Object


clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait


 


Methods inherited from interface com.google.common.cache.LoadingCache


asMap, get


 


Methods inherited from interface com.google.common.cache.Cache


cleanUp, get, getAllPresent, getIfPresent, invalidate, invalidateAll, invalidateAll, put, size, stats


 


Methods inherited from interface com.google.common.base.Function


equals


 








Constructor Detail




AbstractLoadingCache
protected AbstractLoadingCache()

Constructor for use by subclasses.









Method Detail




getUnchecked
public V getUnchecked(K key)

Description copied from interface: Cache
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. 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.


Specified by:
getUnchecked in interface Cache<K,V>
Specified by:
getUnchecked in interface LoadingCache<K,V>
Overrides:
getUnchecked in class AbstractCache<K,V>








getAll
public ImmutableMap<K,V> getAll(Iterable<? extends K> keys)
                         throws ExecutionException

Description copied from interface: LoadingCache
Returns a map of the values associated with keys, creating or retrieving those values
 if necessary. The returned map contains entries that were already cached, combined with newly
 loaded entries; it will never contain null keys or values.

 Caches loaded by a CacheLoader will issue a single request to
 CacheLoader.loadAll(java.lang.Iterable) for all keys which are not already present in the cache. All
 entries returned by CacheLoader.loadAll(java.lang.Iterable) will be stored in the cache, over-writing
 any previously cached values. This method will throw an exception if
 CacheLoader.loadAll(java.lang.Iterable) returns null, returns a map containing null keys or values,
 or fails to return an entry for each requested key.

 
Note that duplicate elements in keys, as determined by Object.equals(java.lang.Object), will
 be ignored.


Specified by:
getAll in interface LoadingCache<K,V>



Throws:
ExecutionException - if a checked exception was thrown while loading the values





apply
public final V apply(K key)

Description copied from interface: Cache
Discouraged. Provided to satisfy the Function interface; use Cache.get(K, java.util.concurrent.Callable) or
 Cache.getUnchecked(K) instead.


Specified by:
apply in interface Function<K,V>
Specified by:
apply in interface Cache<K,V>
Specified by:
apply in interface LoadingCache<K,V>
Overrides:
apply in class AbstractCache<K,V>








refresh
public void refresh(K key)

Description copied from interface: LoadingCache
Loads a new value for key key, possibly asynchronously. While the new value is loading
 the previous value (if any) will continue to be returned by get(key) unless it is
 evicted. If the new value is loaded successfully it will replace the previous value in the
 cache; if an exception is thrown while refreshing the previous value will remain, and the
 exception will be logged (using Logger) and swallowed.

 Caches loaded by a CacheLoader will call CacheLoader.reload(K, V) if the
 cache currently contains a value for key, and CacheLoader.load(K) otherwise.

 
Returns without doing anything if another thread is currently loading the value for
 key. If the cache loader associated with this cache performs refresh asynchronously
 then this method may return before refresh completes.


Specified by:
refresh in interface LoadingCache<K,V>

















  
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Copyright © 2010-2012. All Rights Reserved.

Method Summary
`V`	`apply(K key)` Discouraged.
`ImmutableMap<K,V>`	`getAll(Iterable<? extends K> keys)` Returns a map of the values associated with `keys`, creating or retrieving those values if necessary.
`V`	`getUnchecked(K key)` Returns the value associated with `key` in this cache, first loading that value if necessary.
`void`	`refresh(K key)` Loads a new value for key `key`, possibly asynchronously.

javadoc.com.google.common.cache.AbstractLoadingCache.html Maven / Gradle / Ivy

com.google.common.cache Class AbstractLoadingCache<K,V>

AbstractLoadingCache

getUnchecked

getAll

apply

refresh

com.google.common.cache
Class AbstractLoadingCache<K,V>