001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017package org.apache.commons.configuration; 018 019/** 020 * <p> 021 * A simple class acting as lock. 022 * </p> 023 * <p> 024 * Instances of this class are used by some configuration classes to synchronize 025 * themselves. 026 * </p> 027 * 028 * @author <a 029 * href="http://commons.apache.org/configuration/team-list.html">Commons 030 * Configuration team</a> 031 * @since 1.7 032 * @version $Id: Lock.java 1301995 2012-03-17 20:24:16Z sebb $ 033 */ 034public class Lock 035{ 036 /** A string used internally to synchronize counter updates. */ 037 private static String counterLock = "Lock"; 038 039 /** A counter for generating unique instance IDs. */ 040 private static int counter; 041 042 /** The name of this lock. */ 043 private final String name; 044 045 /** The unique ID of this lock instance. */ 046 private final int instanceId; 047 048 /** 049 * Creates a new instance of {@code Lock} with the specified name. 050 * 051 * @param name the name of this lock 052 */ 053 public Lock(String name) 054 { 055 this.name = name; 056 synchronized (counterLock) 057 { 058 instanceId = ++counter; 059 } 060 } 061 062 /** 063 * Returns the name of this lock. 064 * 065 * @return the name of this lock 066 */ 067 public String getName() 068 { 069 return name; 070 } 071 072 /** 073 * Returns a string representation of this object. This implementation 074 * returns a string which contains the lock name and the instance ID. 075 * 076 * @return a string for this object 077 */ 078 @Override 079 public String toString() 080 { 081 return "Lock: " + name + " id = " + instanceId + ": " 082 + super.toString(); 083 } 084}