org.springframework.cache.concurrent

Class ConcurrentMapCache

java.lang.Object

org.springframework.cache.support.AbstractValueAdaptingCache

org.springframework.cache.concurrent.ConcurrentMapCache

All Implemented Interfaces:

Cache

public class ConcurrentMapCache
extends AbstractValueAdaptingCache

Simple 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.

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

Modifier	Constructor and Description
	ConcurrentMapCache(java.lang.String name) Create a new ConcurrentMapCache with the specified name.
	ConcurrentMapCache(java.lang.String name, boolean allowNullValues) Create a new ConcurrentMapCache with the specified name.
	ConcurrentMapCache(java.lang.String name, java.util.concurrent.ConcurrentMap<java.lang.Object,java.lang.Object> store, boolean allowNullValues) Create a new ConcurrentMapCache with the specified name and the given internal ConcurrentMap to use.
protected	ConcurrentMapCache(java.lang.String name, java.util.concurrent.ConcurrentMap<java.lang.Object,java.lang.Object> store, boolean allowNullValues, SerializationDelegate serialization) Create a new ConcurrentMapCache with the specified name and the given internal ConcurrentMap to use.

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.
protected java.lang.Object	fromStoreValue(java.lang.Object storeValue) Convert the given value from the internal store to a user value returned from the get method (adapting null).
<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.
java.lang.String	getName() Return the cache name.
java.util.concurrent.ConcurrentMap<java.lang.Object,java.lang.Object>	getNativeCache() Return the underlying native cache provider.
boolean	isStoreByValue() Return whether this cache stores a copy of each entry (true) or a reference (false, default).
protected java.lang.Object	lookup(java.lang.Object key) Perform an actual lookup in the underlying store.
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.
protected java.lang.Object	toStoreValue(java.lang.Object userValue) Convert the given user value, as passed into the put method, to a value in the internal store (adapting null).

Methods inherited from class org.springframework.cache.support.AbstractValueAdaptingCache

get, get, isAllowNullValues, toValueWrapper

Methods inherited from class java.lang.Object

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

Constructor Detail

ConcurrentMapCache

public ConcurrentMapCache(java.lang.String name)

Create a new ConcurrentMapCache with the specified name.

Parameters:

name - the name of the cache

ConcurrentMapCache

public ConcurrentMapCache(java.lang.String name,
                          boolean allowNullValues)

Create a new ConcurrentMapCache with the specified name.

Parameters:

name - the name of the cache

allowNullValues - whether to accept and convert null values for this cache

ConcurrentMapCache

public ConcurrentMapCache(java.lang.String name,
                          java.util.concurrent.ConcurrentMap<java.lang.Object,java.lang.Object> store,
                          boolean allowNullValues)

Create a new ConcurrentMapCache with the specified name and the given internal ConcurrentMap to use.

Parameters:

name - the name of the cache

store - the ConcurrentMap to use as an internal store

allowNullValues - whether to allow null values (adapting them to an internal null holder value)

ConcurrentMapCache

protected ConcurrentMapCache(java.lang.String name,
                             java.util.concurrent.ConcurrentMap<java.lang.Object,java.lang.Object> store,
                             boolean allowNullValues,
                             @Nullable
                             SerializationDelegate serialization)

Create a new ConcurrentMapCache with the specified name and the given internal ConcurrentMap to use. If the SerializationDelegate is specified, store-by-value is enabled

Parameters:

name - the name of the cache

store - the ConcurrentMap to use as an internal store

allowNullValues - 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 reference

Since:

4.3

Method Detail

isStoreByValue

public final boolean isStoreByValue()

Return whether this cache stores a copy of each entry (true) or a reference (false, default). If store by value is enabled, each entry in the cache must be serializable.

Since:

4.3

getName

public final java.lang.String getName()

Description copied from interface: Cache

Return the cache name.

getNativeCache

public final java.util.concurrent.ConcurrentMap<java.lang.Object,java.lang.Object> getNativeCache()

Description copied from interface: Cache

Return the underlying native cache provider.

lookup

@Nullable
protected java.lang.Object lookup(java.lang.Object key)

Description copied from class: AbstractValueAdaptingCache

Perform an actual lookup in the underlying store.

Specified by:

lookup in class AbstractValueAdaptingCache

Parameters:

key - the key whose associated value is to be returned

Returns:

the raw store value for the key, or null if none

get

@Nullable
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

Parameters:

key - the key whose associated value is to be returned

Returns:

the value to which this cache maps the specified key

put

public void put(java.lang.Object key,
                @Nullable
                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.

Parameters:

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

value - the value to be associated with the specified key

putIfAbsent

@Nullable
public Cache.ValueWrapper putIfAbsent(java.lang.Object key,
                                                @Nullable
                                                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.

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.

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.

Parameters:

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

clear

public void clear()

Description copied from interface: Cache

Remove all mappings from the cache.

toStoreValue

protected java.lang.Object toStoreValue(@Nullable
                                        java.lang.Object userValue)

Description copied from class: AbstractValueAdaptingCache

Convert the given user value, as passed into the put method, to a value in the internal store (adapting null).

Overrides:

toStoreValue in class AbstractValueAdaptingCache

Parameters:

userValue - the given user value

Returns:

the value to store

fromStoreValue

protected java.lang.Object fromStoreValue(@Nullable
                                          java.lang.Object storeValue)

Description copied from class: AbstractValueAdaptingCache

Convert the given value from the internal store to a user value returned from the get method (adapting null).

Overrides:

fromStoreValue in class AbstractValueAdaptingCache

Parameters:

storeValue - the store value

Returns:

the value to return to the user