Package com.ibm.icu.impl
Class SoftCache<K,V,D>
- java.lang.Object
-
- com.ibm.icu.impl.CacheBase<K,V,D>
-
- com.ibm.icu.impl.SoftCache<K,V,D>
-
- Type Parameters:
K
- Cache lookup key typeV
- Cache instance value type (must not be a CacheValue)D
- Data type for creating a new instance value
- Direct Known Subclasses:
Calendar.WeekDataCache
,ICUResourceBundleReader.ReaderCache
,TimeZoneFormat.TimeZoneFormatCache
,TimeZoneGenericNames.Cache
,TimeZoneNames.Cache
,TimeZoneNamesImpl.MZ2TZsCache
,TimeZoneNamesImpl.TZ2MZsCache
,ZoneMeta.CustomTimeZoneCache
,ZoneMeta.SystemTimeZoneCache
public abstract class SoftCache<K,V,D> extends CacheBase<K,V,D>
Generic, thread-safe cache implementation, usually storing cached instances inReference
s viaCacheValue
s. To use, instantiate a subclass which implements the createInstance() method, and call get() with the key and the data. The get() call will use the data only if it needs to call createInstance(), otherwise the data is ignored.When caching instances while the CacheValue "strength" is
SOFT
, the Java runtime can later release these instances once they are not used any more at all. If such an instance is then requested again, the getInstance() method will call createInstance() again and reset the CacheValue. The cache holds on to its map of keys to CacheValues forever.A value can be null if createInstance() returns null. In this case, it must do so consistently for the same key and data.
-
-
Constructor Summary
Constructors Constructor Description SoftCache()
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description V
getInstance(K key, D data)
Retrieves an instance from the cache.-
Methods inherited from class com.ibm.icu.impl.CacheBase
createInstance
-
-
-
-
Field Detail
-
map
private java.util.concurrent.ConcurrentHashMap<K,java.lang.Object> map
-
-
Method Detail
-
getInstance
public final V getInstance(K key, D data)
Description copied from class:CacheBase
Retrieves an instance from the cache. Calls createInstance(key, data) if the cache does not already contain an instance with this key. Ignores data if the cache already contains an instance with this key.- Specified by:
getInstance
in classCacheBase<K,V,D>
- Parameters:
key
- Cache lookup key for the requested instancedata
- Data for createInstance() if the instance is not already cached- Returns:
- The requested instance
-
-