1 package org.apache.turbine.services.uniqueid;
2
3
4 /*
5 * Licensed to the Apache Software Foundation (ASF) under one
6 * or more contributor license agreements. See the NOTICE file
7 * distributed with this work for additional information
8 * regarding copyright ownership. The ASF licenses this file
9 * to you under the Apache License, Version 2.0 (the
10 * "License"); you may not use this file except in compliance
11 * with the License. You may obtain a copy of the License at
12 *
13 * http://www.apache.org/licenses/LICENSE-2.0
14 *
15 * Unless required by applicable law or agreed to in writing,
16 * software distributed under the License is distributed on an
17 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
18 * KIND, either express or implied. See the License for the
19 * specific language governing permissions and limitations
20 * under the License.
21 */
22
23
24 import java.security.MessageDigest;
25
26
27 import org.apache.commons.codec.binary.Base64;
28 import org.apache.commons.logging.Log;
29 import org.apache.commons.logging.LogFactory;
30
31 import org.apache.turbine.Turbine;
32 import org.apache.turbine.services.InitializationException;
33 import org.apache.turbine.services.TurbineBaseService;
34 import org.apache.turbine.util.GenerateUniqueId;
35
36 /**
37 * <p> This is an implementation of {@link UniqueIdService}.
38 *
39 * @author <a href="mailto:Rafal.Krzewski@e-point.pl">Rafal Krzewski</a>
40 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
41 * @version $Id: TurbineUniqueIdService.java 1706239 2015-10-01 13:18:35Z tv $
42 */
43 public class TurbineUniqueIdService
44 extends TurbineBaseService
45 implements UniqueIdService
46 {
47 /** Logging */
48 private static Log log = LogFactory.getLog(TurbineUniqueIdService.class);
49
50 /** The identifier of this instance of turbine. */
51 protected static String turbineId = "UNKNOWN";
52
53 protected static String turbineURL = "UNKNOWN";
54
55 protected static int counter;
56
57
58 /**
59 * <p> Initializes the service upon first Turbine.doGet()
60 * invocation.
61 */
62 @Override
63 public void init()
64 throws InitializationException
65 {
66 try
67 {
68 // This might be a problem if the unique Id Service runs
69 // before Turbine got its first request. In this case,
70 // getDefaultServerData will return just a dummy value
71 // which is the same for all instances of Turbine.
72 //
73 // TODO This needs definitely further working.
74 String url = Turbine.getDefaultServerData().toString();
75
76 MessageDigest md = MessageDigest.getInstance("MD5");
77 byte [] bytesId = md.digest(url.getBytes("UTF-8"));
78 turbineId = new String(Base64.encodeBase64(bytesId));
79
80 log.info("This is Turbine instance running at: " + url);
81 log.info("The instance id is #" + turbineId);
82 setInit(true);
83 }
84 catch (Exception e)
85 {
86 throw new InitializationException(
87 "Could not initialize TurbineUniqueId Service", e);
88 }
89 }
90
91 /**
92 * <p> Writes a message to the log upon system shutdown.
93 */
94 @Override
95 public void shutdown()
96 {
97 log.info("Turbine instance running at " + turbineURL + " shutting down.");
98 }
99
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 }