org.springframework.cache.ehcache

Class EhCacheCache

java.lang.Object

org.springframework.cache.ehcache.EhCacheCache

All Implemented Interfaces:

Cache

public class EhCacheCache
extends Object
implements Cache

Cache implementation on top of an Ehcache instance.

Since:

3.1

Author:

Costin Leau, Juergen Hoeller, Stephane Nicoll

Nested Class Summary

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

Cache.ValueRetrievalException, Cache.ValueWrapper

Constructor Summary

Constructors

Constructor and Description
EhCacheCache(Ehcache ehcache) Create an EhCacheCache instance.

Method Summary

Modifier and Type	Method and Description
void	clear() Clear the cache through removing all mappings.
void	evict(Object key) Evict the mapping for this key from this cache if it is present.
boolean	evictIfPresent(Object key) Evict the mapping for this key from this cache if it is present, expecting the key to be immediately invisible for subsequent lookups.
Cache.ValueWrapper	get(Object key) Return the value to which this cache maps the specified key.
<T> T	get(Object key, Callable<T> valueLoader) Return the value to which this cache maps the specified key, obtaining that value from valueLoader if necessary.
<T> T	get(Object key, 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.
String	getName() Return the cache name.
Ehcache	getNativeCache() Return the underlying native cache provider.
boolean	invalidate() Invalidate the cache through removing all mappings, expecting all entries to be immediately invisible for subsequent lookups.
void	put(Object key, Object value) Associate the specified value with the specified key in this cache.
Cache.ValueWrapper	putIfAbsent(Object key, 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

Constructor Detail

EhCacheCache

public EhCacheCache(Ehcache ehcache)

Create an EhCacheCache instance.

Parameters:

ehcache - the backing Ehcache instance

Method Detail

getName

public final String getName()

Description copied from interface: Cache

Return the cache name.

Specified by:

getName in interface Cache

getNativeCache

public final Ehcache getNativeCache()

Description copied from interface: Cache

Return the underlying native cache provider.

Specified by:

getNativeCache in interface Cache

get

@Nullable
public Cache.ValueWrapper get(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), Cache.get(Object, Callable)

get

@Nullable
public <T> T get(Object key,
                           @Nullable
                           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

@Nullable
public <T> T get(Object key,
                           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

See Also:

Cache.get(Object)

put

public void put(Object key,
                @Nullable
                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.

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.

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

See Also:

Cache.putIfAbsent(Object, Object)

putIfAbsent

@Nullable
public Cache.ValueWrapper putIfAbsent(Object key,
                                                @Nullable
                                                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:

 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.

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.

See Also:

Cache.put(Object, Object)

evict

public void evict(Object key)

Description copied from interface: 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.

Specified by:

evict in interface Cache

Parameters:

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

See Also:

Cache.evictIfPresent(Object)

evictIfPresent

public boolean evictIfPresent(Object key)

Description copied from interface: 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.

Specified by:

evictIfPresent in interface Cache

Parameters:

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

Returns:

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)

See Also:

Cache.evict(Object)

clear

public void clear()

Description copied from interface: 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.

Specified by:

clear in interface Cache

See Also:

Cache.invalidate()

invalidate

public boolean invalidate()

Description copied from interface: Cache

Invalidate the cache through removing all mappings, expecting all entries to be immediately invisible for subsequent lookups.

Specified by:

invalidate in interface Cache

Returns:

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)

See Also:

Cache.clear()