Package io.lettuce.core.support.caching

Interface CacheFrontend<K,V>

Type Parameters:

K - Key type.

V - Value type.

All Superinterfaces:

AutoCloseable, Closeable

All Known Implementing Classes:

ClientSideCaching

public interface CacheFrontend<K,V>
extends Closeable

Interface defining a cache frontend for common cache retrieval operations that using Redis server-side caching assistance.

Since:

6.0

Author:

Mark Paluch

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	CacheFrontend.ValueRetrievalException	Wrapper exception to be thrown from get(Object, Callable) in case of the value loader callback failing with an exception.

Method Summary

Modifier and Type	Method	Description
void	close()	Closes this cache frontend and releases any system resources associated with it.
V	get(K key)	Return the value to which this cache maps the specified key.
V	get(K key, Callable<V> valueLoader)	Return the value to which this cache maps the specified key, obtaining that value from valueLoader if necessary.

Method Detail

get

V get(K key)

Return the value to which this cache maps the specified key.

Note: This method does not allow for differentiating between a cached null value and no cache entry found at all.

Parameters:

key - the key whose associated value is to be returned.

Returns:

the value to which this cache maps the specified key (which may be null itself), or also null if the cache contains no mapping for this key.

See Also:

CacheAccessor.get(Object), RedisCache.get(Object)

get

V get(K key,
      Callable<V> valueLoader)

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 the valueLoader throws an exception, it is wrapped in a CacheFrontend.ValueRetrievalException

Parameters:

key - the key whose associated value is to be returned

valueLoader - the value loader that is used to obtain the value if the client-side cache and Redis cache are not associated with a value.

Returns:

the value to which this cache maps the specified key.

Throws:

CacheFrontend.ValueRetrievalException - if the valueLoader throws an exception or returns a null value.

close

void close()

Closes this cache frontend and releases any system resources associated with it. If the frontend is already closed then invoking this method has no effect.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable