001/**
002 *
003 * Copyright (c) 2014, the Railo Company Ltd. All rights reserved.
004 *
005 * This library is free software; you can redistribute it and/or
006 * modify it under the terms of the GNU Lesser General Public
007 * License as published by the Free Software Foundation; either 
008 * version 2.1 of the License, or (at your option) any later version.
009 * 
010 * This library is distributed in the hope that it will be useful,
011 * but WITHOUT ANY WARRANTY; without even the implied warranty of
012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013 * Lesser General Public License for more details.
014 * 
015 * You should have received a copy of the GNU Lesser General Public 
016 * License along with this library.  If not, see <http://www.gnu.org/licenses/>.
017 * 
018 **/
019package lucee.commons.lock;
020
021import lucee.runtime.exp.PageException;
022
023
024public interface Lock {
025        
026        public void lock(long timeout) throws PageException;
027
028        public void unlock();
029        
030        /**
031     * Returns an estimate of the number of threads waiting to
032     * acquire this lock.  The value is only an estimate because the number of
033     * threads may change dynamically while this method traverses
034     * internal data structures.  This method is designed for use in
035     * monitoring of the system state, not for synchronization
036     * control.
037     *
038     * @return the estimated number of threads waiting for this lock
039     */
040    public int getQueueLength();
041}