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 */
017 package org.apache.activemq.transport.discovery.zeroconf;
018
019 import java.io.IOException;
020 import java.net.InetAddress;
021 import java.net.UnknownHostException;
022 import java.util.HashMap;
023 import java.util.Iterator;
024 import java.util.Map;
025 import java.util.concurrent.CopyOnWriteArrayList;
026 import javax.jmdns.JmDNS;
027 import javax.jmdns.ServiceEvent;
028 import javax.jmdns.ServiceInfo;
029 import javax.jmdns.ServiceListener;
030
031 import org.apache.activemq.command.DiscoveryEvent;
032 import org.apache.activemq.transport.discovery.DiscoveryAgent;
033 import org.apache.activemq.transport.discovery.DiscoveryListener;
034 import org.apache.activemq.util.JMSExceptionSupport;
035 import org.apache.activemq.util.MapHelper;
036 import org.slf4j.Logger;
037 import org.slf4j.LoggerFactory;
038
039 /**
040 * A {@link DiscoveryAgent} using <a href="http://www.zeroconf.org/">Zeroconf</a>
041 * via the <a href="http://jmdns.sf.net/">jmDNS</a> library
042 *
043 *
044 */
045 public class ZeroconfDiscoveryAgent implements DiscoveryAgent, ServiceListener {
046 private static final Logger LOG = LoggerFactory.getLogger(ZeroconfDiscoveryAgent.class);
047
048 private static final String TYPE_SUFFIX = "ActiveMQ-5.";
049
050 private JmDNS jmdns;
051 private InetAddress localAddress;
052 private String localhost;
053 private int weight;
054 private int priority;
055
056 private DiscoveryListener listener;
057 private String group = "default";
058 private final CopyOnWriteArrayList<ServiceInfo> serviceInfos = new CopyOnWriteArrayList<ServiceInfo>();
059
060 // DiscoveryAgent interface
061 // -------------------------------------------------------------------------
062 public void start() throws Exception {
063 if (group == null) {
064 throw new IOException("You must specify a group to discover");
065 }
066 String type = getType();
067 if (!type.endsWith(".")) {
068 LOG.warn("The type '" + type + "' should end with '.' to be a valid Rendezvous type");
069 type += ".";
070 }
071 try {
072 // force lazy construction
073 getJmdns();
074 if (listener != null) {
075 LOG.info("Discovering service of type: " + type);
076 jmdns.addServiceListener(type, this);
077 }
078 } catch (IOException e) {
079 JMSExceptionSupport.create("Failed to start JmDNS service: " + e, e);
080 }
081 }
082
083 public void stop() {
084 if (jmdns != null) {
085 for (Iterator<ServiceInfo> iter = serviceInfos.iterator(); iter.hasNext();) {
086 ServiceInfo si = iter.next();
087 jmdns.unregisterService(si);
088 }
089
090 // Close it down async since this could block for a while.
091 final JmDNS closeTarget = jmdns;
092 Thread thread = new Thread() {
093 public void run() {
094 try {
095 JmDNSFactory.onClose(getLocalAddress(), closeTarget);
096 } catch (IOException e) {
097 LOG.debug("Error closing JmDNS " + getLocalhost() + ". This exception will be ignored.", e);
098 }
099 }
100 };
101
102 thread.setDaemon(true);
103 thread.start();
104
105 jmdns = null;
106 }
107 }
108
109 public void registerService(String name) throws IOException {
110 ServiceInfo si = createServiceInfo(name, new HashMap());
111 serviceInfos.add(si);
112 getJmdns().registerService(si);
113 }
114
115 // ServiceListener interface
116 // -------------------------------------------------------------------------
117 public void addService(JmDNS jmDNS, String type, String name) {
118 if (LOG.isDebugEnabled()) {
119 LOG.debug("addService with type: " + type + " name: " + name);
120 }
121 if (listener != null) {
122 listener.onServiceAdd(new DiscoveryEvent(name));
123 }
124 jmDNS.requestServiceInfo(type, name);
125 }
126
127 public void removeService(JmDNS jmDNS, String type, String name) {
128 if (LOG.isDebugEnabled()) {
129 LOG.debug("removeService with type: " + type + " name: " + name);
130 }
131 if (listener != null) {
132 listener.onServiceRemove(new DiscoveryEvent(name));
133 }
134 }
135
136 public void serviceAdded(ServiceEvent event) {
137 addService(event.getDNS(), event.getType(), event.getName());
138 }
139
140 public void serviceRemoved(ServiceEvent event) {
141 removeService(event.getDNS(), event.getType(), event.getName());
142 }
143
144 public void serviceResolved(ServiceEvent event) {
145 }
146
147 public void resolveService(JmDNS jmDNS, String type, String name, ServiceInfo serviceInfo) {
148 }
149
150 public int getPriority() {
151 return priority;
152 }
153
154 public void setPriority(int priority) {
155 this.priority = priority;
156 }
157
158 public int getWeight() {
159 return weight;
160 }
161
162 public void setWeight(int weight) {
163 this.weight = weight;
164 }
165
166 public JmDNS getJmdns() throws IOException {
167 if (jmdns == null) {
168 jmdns = createJmDNS();
169 }
170 return jmdns;
171 }
172
173 public void setJmdns(JmDNS jmdns) {
174 this.jmdns = jmdns;
175 }
176
177 public InetAddress getLocalAddress() throws UnknownHostException {
178 if (localAddress == null) {
179 localAddress = createLocalAddress();
180 }
181 return localAddress;
182 }
183
184 public void setLocalAddress(InetAddress localAddress) {
185 this.localAddress = localAddress;
186 }
187
188 public String getLocalhost() {
189 return localhost;
190 }
191
192 public void setLocalhost(String localhost) {
193 this.localhost = localhost;
194 }
195
196 // Implementation methods
197 // -------------------------------------------------------------------------
198 protected ServiceInfo createServiceInfo(String name, Map map) {
199 int port = MapHelper.getInt(map, "port", 0);
200
201 String type = getType();
202
203 if (LOG.isDebugEnabled()) {
204 LOG.debug("Registering service type: " + type + " name: " + name + " details: " + map);
205 }
206 return ServiceInfo.create(type, name + "." + type, port, weight, priority, "");
207 }
208
209 protected JmDNS createJmDNS() throws IOException {
210 return JmDNSFactory.create(getLocalAddress());
211 }
212
213 protected InetAddress createLocalAddress() throws UnknownHostException {
214 if (localhost != null) {
215 return InetAddress.getByName(localhost);
216 }
217 return InetAddress.getLocalHost();
218 }
219
220 public void setDiscoveryListener(DiscoveryListener listener) {
221 this.listener = listener;
222 }
223
224 public String getGroup() {
225 return group;
226 }
227
228 public void setGroup(String group) {
229 this.group = group;
230 }
231
232 public String getType() {
233 return "_" + group + "." + TYPE_SUFFIX;
234 }
235
236 public void serviceFailed(DiscoveryEvent event) throws IOException {
237 // TODO: is there a way to notify the JmDNS that the service failed?
238 }
239
240 }