/*
* Copyright (C) 2011 The Guava Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.glassfish.jersey.internal.guava;
import java.util.concurrent.Callable;
/**
* A semi-persistent mapping from keys to values. Cache entries are manually added using
* {@link #get(Object, Callable)} or {@link #put(Object, Object)}, and are stored in the cache until
* either evicted or manually invalidated.
* <p>
* <p>Implementations of this interface are expected to be thread-safe, and can be safely accessed
* by multiple concurrent threads.
* <p>
* <p>Note that while this class is still annotated as {@link Beta}, the API is frozen from a
* consumer's standpoint. In other words existing methods are all considered {@code non-Beta} and
* won't be changed without going through an 18 month deprecation cycle; however new methods may be
* added at any time.
*
* @author Charles Fry
* @since 10.0
*/
public interface Cache<K, V> {
/**
* Returns the value associated with {@code key} in this cache, or {@code null} if there is no
* cached value for {@code key}.
*
* @since 11.0
*/
V getIfPresent(Object key);
/**
* Associates {@code value} with {@code key} in this cache. If the cache previously contained a
* value associated with {@code key}, the old value is replaced by {@code value}.
* <p>
* <p>Prefer {@link #get(Object, Callable)} when using the conventional "if cached, return;
* otherwise create, cache and return" pattern.
*
* @since 11.0
*/
void put(K key, V value);
}