diff -r 000000000000 -r e4345a26f81f org/sonews/util/TimeoutMap.java --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/org/sonews/util/TimeoutMap.java Wed Aug 26 10:55:59 2009 +0200 @@ -0,0 +1,145 @@ +/* + * SONEWS News Server + * see AUTHORS for the list of contributors + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ + +package org.sonews.util; + +import java.util.HashMap; +import java.util.HashSet; +import java.util.Map; +import java.util.Set; +import java.util.concurrent.ConcurrentHashMap; + +/** + * Implementation of a Map that will loose its stored values after a + * configurable amount of time. + * This class may be used to cache config values for example. + * @author Christian Lins + * @since sonews/0.5.0 + */ +public class TimeoutMap extends ConcurrentHashMap +{ + + private static final long serialVersionUID = 453453467700345L; + + private int timeout = 60000; // 60 sec + private transient Map timeoutMap = new HashMap(); + + /** + * Constructor. + * @param timeout Timeout in milliseconds + */ + public TimeoutMap(final int timeout) + { + this.timeout = timeout; + } + + /** + * Uses default timeout (60 sec). + */ + public TimeoutMap() + { + } + + /** + * + * @param key + * @return true if key is still valid. + */ + protected boolean checkTimeOut(Object key) + { + synchronized(this.timeoutMap) + { + if(this.timeoutMap.containsKey(key)) + { + long keytime = this.timeoutMap.get(key); + if((System.currentTimeMillis() - keytime) < this.timeout) + { + return true; + } + else + { + remove(key); + return false; + } + } + else + { + return false; + } + } + } + + @Override + public boolean containsKey(Object key) + { + return checkTimeOut(key); + } + + @Override + public synchronized V get(Object key) + { + if(checkTimeOut(key)) + { + return super.get(key); + } + else + { + return null; + } + } + + @Override + public V put(K key, V value) + { + synchronized(this.timeoutMap) + { + removeStaleKeys(); + this.timeoutMap.put(key, System.currentTimeMillis()); + return super.put(key, value); + } + } + + /** + * @param arg0 + * @return + */ + @Override + public V remove(Object arg0) + { + synchronized(this.timeoutMap) + { + this.timeoutMap.remove(arg0); + V val = super.remove(arg0); + return val; + } + } + + protected void removeStaleKeys() + { + synchronized(this.timeoutMap) + { + Set keySet = new HashSet(this.timeoutMap.keySet()); + for(Object key : keySet) + { + // The key/value is removed by the checkTimeOut() method if true + checkTimeOut(key); + } + } + } + +}