com.google.gerrit.server.cache.Cache Maven / Gradle / Ivy
// Copyright (C) 2009 The Android Open Source Project
//
// 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 com.google.gerrit.server.cache;
import java.util.concurrent.TimeUnit;
/**
* A fast in-memory and/or on-disk based cache.
*
* @type type of key used to lookup entries in the cache.
* @type type of value stored within each cache entry.
*/
public interface Cache {
/** Get the element from the cache, or null if not stored in the cache. */
public V get(K key);
/** Put one element into the cache, replacing any existing value. */
public void put(K key, V value);
/** Remove any existing value from the cache, no-op if not present. */
public void remove(K key);
/** Remove all cached items. */
public void removeAll();
/**
* Get the time an element will survive in the cache.
*
* @param unit desired units of the return value.
* @return time an item can live before being purged.
*/
public long getTimeToLive(TimeUnit unit);
}