/**
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.activemq.transport.discovery.rendezvous;
import java.io.IOException;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import javax.jmdns.JmDNS;
import javax.jmdns.ServiceEvent;
import javax.jmdns.ServiceInfo;
import javax.jmdns.ServiceListener;
import org.apache.activemq.command.DiscoveryEvent;
import org.apache.activemq.transport.discovery.DiscoveryAgent;
import org.apache.activemq.transport.discovery.DiscoveryListener;
import org.apache.activemq.util.JMSExceptionSupport;
import org.apache.activemq.util.MapHelper;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import edu.emory.mathcs.backport.java.util.concurrent.CopyOnWriteArrayList;
/**
* A {@link DiscoveryAgent} using <a href="http://www.zeroconf.org/">Zeroconf</a>
* via the <a href="http://jmdns.sf.net/">jmDNS</a> library
*
* @version $Revision$
*/
public class RendezvousDiscoveryAgent implements DiscoveryAgent, ServiceListener {
private static final Log log = LogFactory.getLog(RendezvousDiscoveryAgent.class);
private static final String TYPE_SUFFIX = "ActiveMQ-4.";
private JmDNS jmdns;
private InetAddress localAddress;
private String localhost;
private int weight = 0;
private int priority = 0;
private DiscoveryListener listener;
private String group = "default";
private final CopyOnWriteArrayList serviceInfos = new CopyOnWriteArrayList();
private String brokerName;
// DiscoveryAgent interface
//-------------------------------------------------------------------------
public void start() throws Exception {
if (group == null) {
throw new IOException("You must specify a group to discover");
}
String type = getType();
if (!type.endsWith(".")) {
log.warn("The type '" + type + "' should end with '.' to be a valid Rendezvous type");
type += ".";
}
try {
// force lazy construction
getJmdns();
if (listener!=null) {
log.info("Discovering service of type: " +type);
jmdns.addServiceListener(type, this);
}
}
catch (IOException e) {
JMSExceptionSupport.create("Failed to start JmDNS service: " + e, e);
}
}
public void stop() {
if( jmdns!=null ) {
for (Iterator iter = serviceInfos.iterator(); iter.hasNext();) {
ServiceInfo si = (ServiceInfo) iter.next();
jmdns.unregisterService(si);
}
// Close it down async since this could block for a while.
final JmDNS closeTarget = jmdns;
Thread thread = new Thread() {
public void run() {
closeTarget.close();
}
};
thread.setDaemon(true);
thread.start();
jmdns=null;
}
}
public void registerService(String name) throws IOException {
ServiceInfo si = createServiceInfo(name, new HashMap());
serviceInfos.add(si);
getJmdns().registerService(si);
}
// ServiceListener interface
//-------------------------------------------------------------------------
public void addService(JmDNS jmDNS, String type, String name) {
if (log.isDebugEnabled()) {
log.debug("addService with type: " + type + " name: " + name);
}
if( listener!=null )
listener.onServiceAdd(new DiscoveryEvent(name));
jmDNS.requestServiceInfo(type, name);
}
public void removeService(JmDNS jmDNS, String type, String name) {
if (log.isDebugEnabled()) {
log.debug("removeService with type: " + type + " name: " + name);
}
if( listener!=null )
listener.onServiceRemove(new DiscoveryEvent(name));
}
public void serviceAdded(ServiceEvent event) {
addService(event.getDNS(), event.getType(), event.getName());
}
public void serviceRemoved(ServiceEvent event) {
removeService(event.getDNS(), event.getType(), event.getName());
}
public void serviceResolved(ServiceEvent event) {
}
public void resolveService(JmDNS jmDNS, String type, String name, ServiceInfo serviceInfo) {
}
public int getPriority() {
return priority;
}
public void setPriority(int priority) {
this.priority = priority;
}
public int getWeight() {
return weight;
}
public void setWeight(int weight) {
this.weight = weight;
}
public JmDNS getJmdns() throws IOException {
if (jmdns == null) {
jmdns = createJmDNS();
}
return jmdns;
}
public void setJmdns(JmDNS jmdns) {
this.jmdns = jmdns;
}
public InetAddress getLocalAddress() throws UnknownHostException {
if (localAddress == null) {
localAddress = createLocalAddress();
}
return localAddress;
}
public void setLocalAddress(InetAddress localAddress) {
this.localAddress = localAddress;
}
public String getLocalhost() {
return localhost;
}
public void setLocalhost(String localhost) {
this.localhost = localhost;
}
// Implementation methods
//-------------------------------------------------------------------------
protected ServiceInfo createServiceInfo(String name, Map map) {
int port = MapHelper.getInt(map, "port", 0);
String type = getType();
if (log.isDebugEnabled()) {
log.debug("Registering service type: " + type + " name: " + name + " details: " + map);
}
return new ServiceInfo(type, name+"."+type, port, weight, priority, "");
}
protected JmDNS createJmDNS() throws IOException {
return JmDNSFactory.create(getLocalAddress());
}
protected InetAddress createLocalAddress() throws UnknownHostException {
if (localhost != null) {
return InetAddress.getByName(localhost);
}
return InetAddress.getLocalHost();
}
public void setDiscoveryListener(DiscoveryListener listener) {
this.listener = listener;
}
public String getGroup() {
return group;
}
public void setGroup(String group) {
this.group=group;
}
public String getType() {
return "_" + group+"."+TYPE_SUFFIX;
}
public void setBrokerName(String brokerName) {
this.brokerName = brokerName;
}
public void serviceFailed(DiscoveryEvent event) throws IOException {
// TODO: is there a way to notify the JmDNS that the service failed?
}
}