public class ConcurrentMapCache extends AbstractValueAdaptingCache
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.
Cache.ValueRetrievalException, Cache.ValueWrapper| Modifier | Constructor and Description |
|---|---|
|
ConcurrentMapCache(String name)
Create a new ConcurrentMapCache with the specified name.
|
|
ConcurrentMapCache(String name,
boolean allowNullValues)
Create a new ConcurrentMapCache with the specified name.
|
|
ConcurrentMapCache(String name,
ConcurrentMap<Object,Object> store,
boolean allowNullValues)
Create a new ConcurrentMapCache with the specified name and the
given internal
ConcurrentMap to use. |
protected |
ConcurrentMapCache(String name,
ConcurrentMap<Object,Object> store,
boolean allowNullValues,
SerializationDelegate serialization)
Create a new ConcurrentMapCache with the specified name and the
given internal
ConcurrentMap to use. |
| 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.
|
protected Object |
fromStoreValue(Object storeValue)
Convert the given value from the internal store to a user value
returned from the get method (adapting
null). |
<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. |
String |
getName()
Return the cache name.
|
ConcurrentMap<Object,Object> |
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.
|
boolean |
isStoreByValue()
Return whether this cache stores a copy of each entry (
true) or
a reference (false, default). |
protected Object |
lookup(Object key)
Perform an actual lookup in the underlying store.
|
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.
|
protected Object |
toStoreValue(Object userValue)
Convert the given user value, as passed into the put method,
to a value in the internal store (adapting
null). |
get, get, isAllowNullValues, toValueWrapperpublic ConcurrentMapCache(String name)
name - the name of the cachepublic ConcurrentMapCache(String name, boolean allowNullValues)
name - the name of the cacheallowNullValues - whether to accept and convert null
values for this cachepublic ConcurrentMapCache(String name, ConcurrentMap<Object,Object> store, boolean allowNullValues)
ConcurrentMap to use.name - the name of the cachestore - the ConcurrentMap to use as an internal storeallowNullValues - whether to allow null values
(adapting them to an internal null holder value)protected ConcurrentMapCache(String name, ConcurrentMap<Object,Object> store, boolean allowNullValues, @Nullable SerializationDelegate serialization)
ConcurrentMap to use. If the
SerializationDelegate is specified,
store-by-value is enabledname - the name of the cachestore - the ConcurrentMap to use as an internal storeallowNullValues - 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 referencepublic final boolean isStoreByValue()
true) or
a reference (false, default). If store by value is enabled, each
entry in the cache must be serializable.public final String getName()
Cachepublic final ConcurrentMap<Object,Object> getNativeCache()
Cache@Nullable protected Object lookup(Object key)
AbstractValueAdaptingCachelookup in class AbstractValueAdaptingCachekey - the key whose associated value is to be returnednull if none@Nullable public <T> T get(Object key, Callable<T> valueLoader)
CachevalueLoader 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
key - the key whose associated value is to be returnedCache.get(Object)public void put(Object key, @Nullable Object value)
CacheIf 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.
key - the key with which the specified value is to be associatedvalue - the value to be associated with the specified keyCache.putIfAbsent(Object, Object)@Nullable public Cache.ValueWrapper putIfAbsent(Object key, @Nullable Object value)
CacheThis is equivalent to:
ValueWrapper existingValue = cache.get(key);
if (existingValue == null) {
cache.put(key, value);
}
return existingValue;
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.
key - the key with which the specified value is to be associatedvalue - the value to be associated with the specified keynull 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.Cache.put(Object, Object)public void evict(Object key)
CacheActual 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.
key - the key whose mapping is to be removed from the cacheCache.evictIfPresent(Object)public boolean evictIfPresent(Object key)
CacheThe 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.
key - the key whose mapping is to be removed from the cachetrue 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)Cache.evict(Object)public void clear()
CacheActual 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.
Cache.invalidate()public boolean invalidate()
Cachetrue if the cache was known to have mappings before,
false if it did not (or if prior presence of entries could
not be determined)Cache.clear()protected Object toStoreValue(@Nullable Object userValue)
AbstractValueAdaptingCachenull).toStoreValue in class AbstractValueAdaptingCacheuserValue - the given user valueprotected Object fromStoreValue(@Nullable Object storeValue)
AbstractValueAdaptingCachenull).fromStoreValue in class AbstractValueAdaptingCachestoreValue - the store value