程序包 cn.taketoday.cache.concurrent

类 ConcurrentMapCache

java.lang.Object
cn.taketoday.cache.support.AbstractValueAdaptingCache
cn.taketoday.cache.concurrent.ConcurrentMapCache
所有已实现的接口:
Cache
public class ConcurrentMapCache extends AbstractValueAdaptingCache
Simple Cache implementation based on the core JDK java.util.concurrent package.

Useful for testing or simple caching scenarios, typically in combination with SimpleCacheManager or dynamically through ConcurrentMapCacheManager.

Note: As ConcurrentHashMap (the default implementation used) does not allow for null values to be stored, this class will replace them with a predefined internal object. This behavior can be changed through the ConcurrentMapCache(String, ConcurrentMap, boolean) constructor.

从以下版本开始:
2019-12-17 12:29
作者:
Costin Leau, Juergen Hoeller, Stephane Nicoll, TODAY
另请参阅:

  • 构造器详细资料

    • ConcurrentMapCache

      public ConcurrentMapCache(String name)
      Create a new ConcurrentMapCache with the specified name.
      参数:
      name - the name of the cache

    • ConcurrentMapCache

      public ConcurrentMapCache(String name, boolean allowNullValues)
      Create a new ConcurrentMapCache with the specified name.
      参数:
      name - the name of the cache
      allowNullValues - whether to accept and convert null values for this cache

    • ConcurrentMapCache

      public ConcurrentMapCache(String name, ConcurrentMap<Object,Object> store, boolean allowNullValues)
      Create a new ConcurrentMapCache with the specified name and the given internal ConcurrentMap to use.
      参数:
      name - the name of the cache
      store - the ConcurrentMap to use as an internal store
      allowNullValues - whether to allow null values (adapting them to an internal null holder value)

    • ConcurrentMapCache

      protected ConcurrentMapCache(String name, ConcurrentMap<Object,Object> store, boolean allowNullValues, @Nullable cn.taketoday.core.serializer.support.SerializationDelegate serialization)
      Create a new ConcurrentMapCache with the specified name and the given internal ConcurrentMap to use. If the SerializationDelegate is specified, store-by-value is enabled
      参数:
      name - the name of the cache
      store - the ConcurrentMap to use as an internal store
      allowNullValues - whether to allow null values (adapting them to an internal null holder value)
      serialization - the SerializationDelegate to use to serialize cache entry or null to store the reference
      从以下版本开始:
      4.0

  • 方法详细资料

    • isStoreByValue

      public final boolean isStoreByValue()
      Return whether this cache stores a copy of each entry (true) or a reference (false, default). If store by value is enabled, each entry in the cache must be serializable.
      从以下版本开始:
      4.0

    • getName

      public final String getName()
      从接口复制的说明: Cache
      Return the cache name.

    • getNativeCache

      public final ConcurrentMap<Object,Object> getNativeCache()
      从接口复制的说明: Cache
      Return the underlying native cache provider.

    • lookup

      @Nullable protected Object lookup(Object key)
      从类复制的说明: AbstractValueAdaptingCache
      Perform an actual lookup in the underlying store.
      指定者:
      lookup 在类中 AbstractValueAdaptingCache
      参数:
      key - the key whose associated value is to be returned
      返回:
      the raw store value for the key, or null if none

    • get

      @Nullable public <T> T get(Object key, Callable<T> valueLoader)
      从接口复制的说明: Cache
      Return the value to which this cache maps the specified key, obtaining that value from valueLoader if necessary. This method provides a simple substitute for the conventional "if cached, return; otherwise create, cache and return" pattern.

      If possible, implementations should ensure that the loading operation is synchronized so that the specified valueLoader is only called once in case of concurrent access on the same key.

      If the valueLoader throws an exception, it is wrapped in a Cache.ValueRetrievalException

      参数:
      key - the key whose associated value is to be returned
      返回:
      the value to which this cache maps the specified key
      另请参阅:

    • put

      public void put(Object key, @Nullable Object value)
      从接口复制的说明: Cache
      Associate the specified value with the specified key in this cache.

      If the cache previously contained a mapping for this key, the old value is replaced by the specified value.

      Actual registration may be performed in an asynchronous or deferred fashion, with subsequent lookups possibly not seeing the entry yet. This may for example be the case with transactional cache decorators. Use Cache.putIfAbsent(java.lang.Object, java.lang.Object) for guaranteed immediate registration.

      参数:
      key - the key with which the specified value is to be associated
      value - the value to be associated with the specified key
      另请参阅:

    • putIfAbsent

      @Nullable public Cache.ValueWrapper putIfAbsent(Object key, @Nullable Object value)
      从接口复制的说明: Cache
      Atomically associate the specified value with the specified key in this cache if it is not set already.

      This is equivalent to: 

      
 ValueWrapper existingValue = cache.get(key);
 if (existingValue == null) {
     cache.put(key, value);
 }
 return existingValue;
      except that the action is performed atomically. While all out-of-the-box CacheManager implementations are able to perform the put atomically, the operation may also be implemented in two steps, e.g. with a check for presence and a subsequent put, in a non-atomic way. Check the documentation of the native cache implementation that you are using for more details.

      The default implementation delegates to Cache.get(Object) and Cache.put(Object, Object) along the lines of the code snippet above.

      参数:
      key - the key with which the specified value is to be associated
      value - the value to be associated with the specified key
      返回:
      the value to which this cache maps the specified key (which may be null itself), or also null if the cache did not contain any mapping for that key prior to this call. Returning null is therefore an indicator that the given value has been associated with the key.
      另请参阅:

    • evict

      public void evict(Object key)
      从接口复制的说明: Cache
      Evict the mapping for this key from this cache if it is present.

      Actual eviction may be performed in an asynchronous or deferred fashion, with subsequent lookups possibly still seeing the entry. This may for example be the case with transactional cache decorators. Use Cache.evictIfPresent(java.lang.Object) for guaranteed immediate removal.

      参数:
      key - the key whose mapping is to be removed from the cache
      另请参阅:

    • evictIfPresent

      public boolean evictIfPresent(Object key)
      从接口复制的说明: Cache
      Evict the mapping for this key from this cache if it is present, expecting the key to be immediately invisible for subsequent lookups.

      The default implementation delegates to Cache.evict(Object), returning false for not-determined prior presence of the key. Cache providers and in particular cache decorators are encouraged to perform immediate eviction if possible (e.g. in case of generally deferred cache operations within a transaction) and to reliably determine prior presence of the given key.

      参数:
      key - the key whose mapping is to be removed from the cache
      返回:
      true if the cache was known to have a mapping for this key before, false if it did not (or if prior presence could not be determined)
      另请参阅:

    • clear

      public void clear()
      从接口复制的说明: Cache
      Clear the cache through removing all mappings.

      Actual clearing may be performed in an asynchronous or deferred fashion, with subsequent lookups possibly still seeing the entries. This may for example be the case with transactional cache decorators. Use Cache.invalidate() for guaranteed immediate removal of entries.

      另请参阅:

    • invalidate

      public boolean invalidate()
      从接口复制的说明: Cache
      Invalidate the cache through removing all mappings, expecting all entries to be immediately invisible for subsequent lookups.
      返回:
      true if the cache was known to have mappings before, false if it did not (or if prior presence of entries could not be determined)
      另请参阅:

    • toStoreValue

      protected Object toStoreValue(@Nullable Object userValue)
      从类复制的说明: AbstractValueAdaptingCache
      Convert the given user value, as passed into the put method, to a value in the internal store (adapting null).
      覆盖:
      toStoreValue 在类中 AbstractValueAdaptingCache
      参数:
      userValue - the given user value
      返回:
      the value to store

    • fromStoreValue

      protected Object fromStoreValue(@Nullable Object storeValue)
      从类复制的说明: AbstractValueAdaptingCache
      Convert the given value from the internal store to a user value returned from the get method (adapting null).
      覆盖:
      fromStoreValue 在类中 AbstractValueAdaptingCache
      参数:
      storeValue - the store value
      返回:
      the value to return to the user