org.axonframework.common.caching

Interface Cache

All Known Implementing Classes:

AbstractCacheAdapter, EhCacheAdapter, JCacheAdapter, NoCache, WeakReferenceCache

public interface Cache

Abstraction for a Caching mechanism. All Axon component rely on this abstraction, so that different providers can be plugged in. In future versions, this abstraction may be replaced with the javax.cache api, as soon as that api is final.

Since:

2.1.2

Author:

Allard Buijze

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	Cache.EntryListener Interface describing callback methods, which are invoked when changes are made in the underlying cache.
static class	Cache.EntryListenerAdapter Adapter implementation for the EntryListener, allowing for overriding only specific callback methods.

Method Summary

Modifier and Type	Method and Description
default <T> T	computeIfAbsent(Object key, Supplier<T> valueSupplier) Returns the value under the given key in the cache.
default <V> void	computeIfPresent(Object key, UnaryOperator<V> update) Perform the update in the value behind the given key.
boolean	containsKey(Object key) Indicates whether there is an item stored under given key.
<K,V> V	get(K key) Returns an item from the cache, or null if no item was stored under that key
void	put(Object key, Object value) Stores the given value in the cache, under given key.
boolean	putIfAbsent(Object key, Object value) Stores the given value in the cache, under given key, if no element is yet available under that key.
Registration	registerCacheEntryListener(Cache.EntryListener cacheEntryListener) Registers the given cacheEntryListener to listen for Cache changes.
boolean	remove(Object key) Removes the entry stored under given key.
default void	removeAll() Remove all stored entries in this cache.

Method Detail

get

<K,V> V get(K key)

Returns an item from the cache, or null if no item was stored under that key

Type Parameters:

K - The type of key used

V - The type of value stored

Parameters:

key - The key under which the item was cached

Returns:

the item stored under the given key

put

void put(Object key,
         Object value)

Stores the given value in the cache, under given key. If an item already exists, it is updated with the new value.

Parameters:

key - The key under which to store the item

value - The item to cache

putIfAbsent

boolean putIfAbsent(Object key,
                    Object value)

Stores the given value in the cache, under given key, if no element is yet available under that key. This operation is performed atomically.

Parameters:

key - The key under which to store the item

value - The item to cache

Returns:

true if no value was previously assigned to the key, false otherwise.

computeIfAbsent

default <T> T computeIfAbsent(Object key,
                              Supplier<T> valueSupplier)

Returns the value under the given key in the cache. If there is no value present, will invoke the given valueSupplier, put the value in the cache and return the produced value.

Parameters:

key - The key under which the item was cached. If not present, this key is used to cache the outcome of the valueSupplier.

valueSupplier - A supplier that lazily supplies the value if there's no key present.

Returns:

The value that is in the cache after the operation. This can be the original value or the one supplied by the valueSupplier.

remove

boolean remove(Object key)

Removes the entry stored under given key. If no such entry exists, nothing happens.

Parameters:

key - The key under which the item was stored

Returns:

true if a value was previously assigned to the key and has been removed, false otherwise.

removeAll

default void removeAll()

Remove all stored entries in this cache.

containsKey

boolean containsKey(Object key)

Indicates whether there is an item stored under given key.

Parameters:

key - The key to check

Returns:

true if an item is available under that key, false otherwise.

registerCacheEntryListener

Registration registerCacheEntryListener(Cache.EntryListener cacheEntryListener)

Registers the given cacheEntryListener to listen for Cache changes.

Parameters:

cacheEntryListener - The listener to register

Returns:

a handle to deregister the listener

computeIfPresent

default <V> void computeIfPresent(Object key,
                                  UnaryOperator<V> update)

Perform the update in the value behind the given key. The update is only executed if there's an entry referencing the key.

Type Parameters:

V - The type of the value to execute the update for.

Parameters:

key - The key to perform an update for, if not empty.

update - The update to perform if the key is present.