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 }