Class AbstractValueAdaptingCache
- java.lang.Object
- org.springframework.cache.support.AbstractValueAdaptingCache
- All Implemented Interfaces:
Cache
- Direct Known Subclasses:
CaffeineCache
,ConcurrentMapCache
,GuavaCache
,JCacheCache
public abstract class AbstractValueAdaptingCache extends Object implements Cache
Common base class forCache
implementations that need to adaptnull
values (and potentially other such special values) before passing them on to the underlying store.Transparently replaces given
null
user values with an internalNullValue.INSTANCE
, if configured to supportnull
values (as indicated byisAllowNullValues()
.- Since:
- 4.2.2
- Author:
- Juergen Hoeller
Nested Class Summary
Nested classes/interfaces inherited from interface org.springframework.cache.Cache
Cache.ValueRetrievalException, Cache.ValueWrapper
Constructor Summary
Constructors Modifier Constructor Description protected
AbstractValueAdaptingCache(boolean allowNullValues)
Create anAbstractValueAdaptingCache
with the given setting.
Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description protected Object
fromStoreValue(Object storeValue)
Convert the given value from the internal store to a user value returned from the get method (adaptingnull
).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.boolean
isAllowNullValues()
Return whethernull
values are allowed in this cache.protected abstract Object
lookup(Object key)
Perform an actual lookup in the underlying store.protected Object
toStoreValue(Object userValue)
Convert the given user value, as passed into the put method, to a value in the internal store (adaptingnull
).protected Cache.ValueWrapper
toValueWrapper(Object storeValue)
Wrap the given store value with aSimpleValueWrapper
, also going throughfromStoreValue(java.lang.Object)
conversion.Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface org.springframework.cache.Cache
clear, evict, get, getName, getNativeCache, put, putIfAbsent
Constructor Detail
AbstractValueAdaptingCache
protected AbstractValueAdaptingCache(boolean allowNullValues)
Create anAbstractValueAdaptingCache
with the given setting.- Parameters:
allowNullValues
- whether to allow fornull
values
Method Detail
isAllowNullValues
public final boolean isAllowNullValues()
Return whethernull
values are allowed in this cache.
get
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 benull
itself) will be returned in aCache.ValueWrapper
.- Specified by:
get
in interfaceCache
- 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 cachednull
value. A straightnull
being returned means that the cache contains no mapping for this key. - See Also:
Cache.get(Object, Class)
get
public <T> T get(Object key, 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 cachednull
value and no cache entry found at all. Use the standardCache.get(Object)
variant for that purpose instead.- Specified by:
get
in interfaceCache
- Parameters:
key
- the key whose associated value is to be returnedtype
- the required type of the returned value (may benull
to bypass a type check; in case of anull
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 alsonull
if the cache contains no mapping for this key - See Also:
Cache.get(Object)
lookup
protected abstract Object lookup(Object key)
Perform an actual lookup in the underlying store.- Parameters:
key
- the key whose associated value is to be returned- Returns:
- the raw store value for the key, or
null
if none
fromStoreValue
protected Object fromStoreValue(Object storeValue)
Convert the given value from the internal store to a user value returned from the get method (adaptingnull
).- Parameters:
storeValue
- the store value- Returns:
- the value to return to the user
toStoreValue
protected Object toStoreValue(Object userValue)
Convert the given user value, as passed into the put method, to a value in the internal store (adaptingnull
).- Parameters:
userValue
- the given user value- Returns:
- the value to store
toValueWrapper
protected Cache.ValueWrapper toValueWrapper(Object storeValue)
Wrap the given store value with aSimpleValueWrapper
, also going throughfromStoreValue(java.lang.Object)
conversion. Useful forget(Object)
andCache.putIfAbsent(Object, Object)
implementations.- Parameters:
storeValue
- the original value- Returns:
- the wrapped value