类 NoOpCache

构造器详细资料

• NoOpCache

  public NoOpCache​(String name)

  Create a NoOpCache instance with the specified name.

  参数:

  name - the name of the cache

方法详细资料

• getName

  public String getName()

  从接口复制的说明: Cache
  Return the cache name.

  指定者:

  getName 在接口中 Cache

• getNativeCache

  public Object getNativeCache()

  从接口复制的说明: Cache
  Return the underlying native cache provider.

  指定者:

  getNativeCache 在接口中 Cache

• get

  @Nullable
  public Cache.ValueWrapper get​(Object key)

  从接口复制的说明: Cache
  Return the value to which this cache maps the specified key.

  Returns null if the cache contains no mapping for this key; otherwise, the cached value (which may be null itself) will be returned in a Cache.ValueWrapper.

  指定者:

  get 在接口中 Cache

  参数:

  key - the key whose associated value is to be returned

  返回:

  the value to which this cache maps the specified key, contained within a Cache.ValueWrapper which may also hold a cached null value. A straight null being returned means that the cache contains no mapping for this key.

  另请参阅:

  Cache.get(Object, Class), Cache.get(Object, Callable)

• get

  @Nullable
  public <T> T get​(Object key,
                   @Nullable
                   Class<T> type)

  从接口复制的说明: Cache
  Return the value to which this cache maps the specified key, generically specifying a type that return value will be cast to.

  Note: This variant of get does not allow for differentiating between a cached null value and no cache entry found at all. Use the standard Cache.get(Object) variant for that purpose instead.

  指定者:

  get 在接口中 Cache

  参数:

  key - the key whose associated value is to be returned

  type - the required type of the returned value (may be null to bypass a type check; in case of a null value found in the cache, the specified type is irrelevant)

  返回:

  the value to which this cache maps the specified key (which may be null itself), or also null if the cache contains no mapping for this key

  另请参阅:

  Cache.get(Object)

• 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

  指定者:

  get 在接口中 Cache

  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:

  Cache.get(Object)

• 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.

  指定者:

  put 在接口中 Cache

  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:

  Cache.putIfAbsent(Object, Object)

• 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.

  指定者:

  putIfAbsent 在接口中 Cache

  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:

  Cache.put(Object, Object)

• 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.

  指定者:

  evict 在接口中 Cache

  参数:

  key - the key whose mapping is to be removed from the cache

  另请参阅:

  Cache.evictIfPresent(Object)

• 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.

  指定者:

  evictIfPresent 在接口中 Cache

  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:

  Cache.evict(Object)

• 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.

  指定者:

  clear 在接口中 Cache

  另请参阅:

  Cache.invalidate()

• 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.

  指定者:

  invalidate 在接口中 Cache

  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:

  Cache.clear()