org.springframework.cache.concurrent

Class 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
    • 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

      All Methods Instance Methods Concrete Methods 
      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 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