public class ConcurrentMapCache extends Object implements Cache
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.ValueWrapper| 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. |
| Modifier and Type | Method and Description |
|---|---|
void |
clear()
Remove all mappings from the cache.
|
void |
evict(Object key)
Evict the mapping for this key from this cache if it is present.
|
protected Object |
fromStoreValue(Object storeValue)
Convert the given value from the internal store to a user value
returned from the get method (adapting
null). |
Cache.ValueWrapper |
get(Object key)
Return the value to which this cache maps the specified key.
|
<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.
|
ConcurrentMap<Object,Object> |
getNativeCache()
Return the the underlying native cache provider.
|
boolean |
isAllowNullValues() |
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). |
public 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)public final String getName()
Cachepublic final ConcurrentMap<Object,Object> getNativeCache()
CachegetNativeCache in interface Cachepublic final boolean isAllowNullValues()
public Cache.ValueWrapper get(Object key)
CacheReturns 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.
get in interface Cachekey - the key whose associated value is to be returnedCache.ValueWrapper which may also hold
a cached null value. A straight null being
returned means that the cache contains no mapping for this key.Cache.get(Object, Class)public <T> T get(Object key, Class<T> type)
CacheNote: 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.
get in interface Cachekey - the key whose associated value is to be returnedtype - 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)null itself), or also null if
the cache contains no mapping for this keyCache.get(Object)public void put(Object key, Object value)
CacheIf the cache previously contained a mapping for this key, the old value is replaced by the specified value.
public Cache.ValueWrapper putIfAbsent(Object key, Object value)
CacheThis is equivalent to:
Object existingValue = cache.get(key);
if (existingValue == null) {
cache.put(key, value);
return null;
} else {
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.putIfAbsent in interface Cachekey - 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.public void evict(Object key)
Cachepublic void clear()
Cacheprotected Object fromStoreValue(Object storeValue)
null).storeValue - the store value