/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.openjpa.lib.util;
import java.util.Map;
/**
* A {@link Map} type that can hold its keys, values, or both with
* weak or soft references.
*
* @author Abe White
*/
public interface ReferenceMap extends Map {
public static final int HARD = 0;
public static final int WEAK = 1;
public static final int SOFT = 2;
/**
* Purge stale entries.
*/
public void removeExpired();
/**
* Overridable callback for when a key reference expires.
*
* @param value the value for the expired key
*/
public void keyExpired(Object value);
/**
* Overridable callback for when a value reference expires.
*
* @param key the key for the expired value
*/
public void valueExpired(Object key);
}