org.springframework.cache.support

Class NoOpCache

java.lang.Object

org.springframework.cache.support.NoOpCache

All Implemented Interfaces:

Cache

public class NoOpCache
extends java.lang.Object
implements Cache

A no operation Cache implementation suitable for disabling caching.

Will simply accept any items into the cache not actually storing them.

Since:

4.3.4

Author:

Costin Leau, Stephane Nicoll

Nested Class Summary

Nested classes/interfaces inherited from interface org.springframework.cache.Cache

Cache.ValueRetrievalException, Cache.ValueWrapper

Field Summary

Fields

Modifier and Type	Field and Description
private java.lang.String	name

Constructor Summary

Constructors

Constructor and Description
NoOpCache(java.lang.String name) Create a NoOpCache instance with the specified name

Method Summary

Modifier and Type	Method and Description
void	clear() Remove all mappings from the cache.
void	evict(java.lang.Object key) Evict the mapping for this key from this cache if it is present.
Cache.ValueWrapper	get(java.lang.Object key) Return the value to which this cache maps the specified key.
<T> T	get(java.lang.Object key, java.util.concurrent.Callable<T> valueLoader) Return the value to which this cache maps the specified key, obtaining that value from valueLoader if necessary.
<T> T	get(java.lang.Object key, java.lang.Class<T> type) Return the value to which this cache maps the specified key, generically specifying a type that return value will be cast to.
java.lang.String	getName() Return the cache name.
java.lang.Object	getNativeCache() Return the underlying native cache provider.
void	put(java.lang.Object key, java.lang.Object value) Associate the specified value with the specified key in this cache.
Cache.ValueWrapper	putIfAbsent(java.lang.Object key, java.lang.Object value) Atomically associate the specified value with the specified key in this cache if it is not set already.

Methods inherited from class java.lang.Object

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

Field Detail

name

private final java.lang.String name

Constructor Detail

NoOpCache

public NoOpCache(java.lang.String name)

Create a NoOpCache instance with the specified name

Parameters:

name - the name of the cache

Method Detail

clear

public void clear()

Description copied from interface: Cache

Remove all mappings from the cache.

Specified by:

clear in interface Cache

evict

public void evict(java.lang.Object key)

Description copied from interface: Cache

Evict the mapping for this key from this cache if it is present.

Specified by:

evict in interface Cache

Parameters:

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

get

public Cache.ValueWrapper get(java.lang.Object key)

Description copied from interface: 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.

Specified by:

get in interface Cache

Parameters:

key - the key whose associated value is to be returned

Returns:

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.

See Also:

Cache.get(Object, Class)

get

public <T> T get(java.lang.Object key,
                 java.lang.Class<T> type)

Description copied from interface: 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.

Specified by:

get in interface Cache

Parameters:

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)

Returns:

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

See Also:

Cache.get(Object)

get

public <T> T get(java.lang.Object key,
                 java.util.concurrent.Callable<T> valueLoader)

Description copied from interface: 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

Specified by:

get in interface Cache

Parameters:

key - the key whose associated value is to be returned

Returns:

the value to which this cache maps the specified key

getName

public java.lang.String getName()

Description copied from interface: Cache

Return the cache name.

Specified by:

getName in interface Cache

getNativeCache

public java.lang.Object getNativeCache()

Description copied from interface: Cache

Return the underlying native cache provider.

Specified by:

getNativeCache in interface Cache

put

public void put(java.lang.Object key,
                java.lang.Object value)

Description copied from interface: 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.

Specified by:

put in interface Cache

Parameters:

key - the key with which the specified value is to be associated

value - the value to be associated with the specified key

putIfAbsent

public Cache.ValueWrapper putIfAbsent(java.lang.Object key,
                                      java.lang.Object value)

Description copied from interface: Cache

Atomically associate the specified value with the specified key in this cache if it is not set already.

This is equivalent to:

 Object existingValue = cache.get(key);
 if (existingValue == null) {
     cache.put(key, value);
     return null;
 } else {
     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.

Specified by:

putIfAbsent in interface Cache

Parameters:

key - the key with which the specified value is to be associated

value - the value to be associated with the specified key

Returns:

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.