001 package org.apache.turbine.services.uniqueid; 002 003 004 /* 005 * Licensed to the Apache Software Foundation (ASF) under one 006 * or more contributor license agreements. See the NOTICE file 007 * distributed with this work for additional information 008 * regarding copyright ownership. The ASF licenses this file 009 * to you under the Apache License, Version 2.0 (the 010 * "License"); you may not use this file except in compliance 011 * with the License. You may obtain a copy of the License at 012 * 013 * http://www.apache.org/licenses/LICENSE-2.0 014 * 015 * Unless required by applicable law or agreed to in writing, 016 * software distributed under the License is distributed on an 017 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 018 * KIND, either express or implied. See the License for the 019 * specific language governing permissions and limitations 020 * under the License. 021 */ 022 023 024 import java.security.MessageDigest; 025 026 027 import org.apache.commons.codec.binary.Base64; 028 import org.apache.commons.logging.Log; 029 import org.apache.commons.logging.LogFactory; 030 031 import org.apache.turbine.Turbine; 032 import org.apache.turbine.services.InitializationException; 033 import org.apache.turbine.services.TurbineBaseService; 034 import org.apache.turbine.util.GenerateUniqueId; 035 036 /** 037 * <p> This is an implementation of {@link UniqueIdService}. 038 * 039 * @author <a href="mailto:Rafal.Krzewski@e-point.pl">Rafal Krzewski</a> 040 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a> 041 * @version $Id: TurbineUniqueIdService.java 1066925 2011-02-03 19:44:37Z ludwig $ 042 */ 043 public class TurbineUniqueIdService 044 extends TurbineBaseService 045 implements UniqueIdService 046 { 047 /** Logging */ 048 private static Log log = LogFactory.getLog(TurbineUniqueIdService.class); 049 050 /** The identifier of this instance of turbine. */ 051 protected static String turbineId = "UNKNOWN"; 052 053 protected static String turbineURL = "UNKNOWN"; 054 055 protected static int counter; 056 057 058 /** 059 * <p> Initializes the service upon first Turbine.doGet() 060 * invocation. 061 */ 062 @Override 063 public void init() 064 throws InitializationException 065 { 066 try 067 { 068 // This might be a problem if the unique Id Service runs 069 // before Turbine got its first request. In this case, 070 // getDefaultServerData will return just a dummy value 071 // which is the same for all instances of Turbine. 072 // 073 // @todo This needs definitely further working. 074 String url = Turbine.getDefaultServerData().toString(); 075 076 MessageDigest md = MessageDigest.getInstance("MD5"); 077 byte [] bytesId = md.digest(url.getBytes("UTF-8")); 078 turbineId = new String(Base64.encodeBase64(bytesId)); 079 080 log.info("This is Turbine instance running at: " + url); 081 log.info("The instance id is #" + turbineId); 082 setInit(true); 083 } 084 catch (Exception e) 085 { 086 throw new InitializationException( 087 "Could not initialize TurbineUniqueId Service", e); 088 } 089 } 090 091 /** 092 * <p> Writes a message to the log upon system shutdown. 093 */ 094 @Override 095 public void shutdown() 096 { 097 log.info("Turbine instance running at " + turbineURL + " shutting down."); 098 } 099 100 /** 101 * <p> Returns an identifier of this Turbine instance that is unique 102 * both on the server and worldwide. This identifier is computed 103 * as an MD5 sum of the URL (including schema, address, port if 104 * different that 80/443 respecively, context and servlet name). 105 * There is an overwhelming probalility that this id will be 106 * different that all other Turbine instances online. 107 * 108 * @return A String with the instance identifier. 109 */ 110 public String getInstanceId() 111 { 112 return turbineId; 113 } 114 115 /** 116 * <p> Returns an identifier that is unique within this turbine 117 * instance, but does not have random-like apearance. 118 * 119 * @return A String with the non-random looking instance 120 * identifier. 121 */ 122 public String getUniqueId() 123 { 124 int current; 125 synchronized (TurbineUniqueIdService.class) 126 { 127 current = counter++; 128 } 129 String id = Integer.toString(current); 130 131 // If you manage to get more than 100 million of ids, you'll 132 // start getting ids longer than 8 characters. 133 if (current < 100000000) 134 { 135 id = ("00000000" + id).substring(id.length()); 136 } 137 return id; 138 } 139 140 /** 141 * <p> Returns a unique identifier that looks like random data. 142 * 143 * @return A String with the random looking instance identifier. 144 */ 145 public String getPseudorandomId() 146 { 147 return GenerateUniqueId.getIdentifier(); 148 } 149 }