com.aspectran.core.util.cache.Cache Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2022 The Aspectran 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.aspectran.core.util.cache;
import java.util.Set;
/**
* A Map-like data structure that stores key-value pairs and provides temporary
* access to it.
*
* @param the type of keys
* @param the type of mapped values
* @since 6.6.7
*/
public interface Cache {
/**
* Gets an entry from the cache.
* @param key the key whose associated value is to be returned
* @return the element, or {@code null}, if it does not exist
*/
V get(K key);
/**
* Removes the specified element from this cache if it is present.
* @param key key with which the specified value is to be associated
*/
void remove(K key);
/**
* Removes all of the elements from this cache.
*/
void clear();
/**
* Returns a {@link Set} view of the keys contained in this cache.
* @return the set view
*/
Set keySet();
/**
* Returns the number of elements in this cache.
* @return the number of elements in this cache
*/
int size();
/**
* Returns {@code true} if this cache contains no key-value mappings.
* @return {@code true} if this cache contains no key-value mappings
*/
boolean isEmpty();
}