/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.remoting.transporter;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.io.Serializable;
import javax.management.MBeanServer;
import javax.management.MBeanServerFactory;
import javax.management.ObjectName;
import org.jboss.logging.Logger;
import org.jboss.remoting.CannotConnectException;
import org.jboss.remoting.Client;
import org.jboss.remoting.InvokerLocator;
import org.jboss.remoting.detection.Detector;
import org.jboss.remoting.detection.ServerInvokerMetadata;
import org.jboss.remoting.detection.multicast.MulticastDetector;
import org.jboss.remoting.invocation.NameBasedInvocation;
import org.jboss.remoting.network.NetworkInstance;
import org.jboss.remoting.network.NetworkRegistry;
/**
* Class to be used as a factory via static method calls to get
* remote proxy to POJO that exists within a external process.
* Note, if using clustered, will use the multicast detector by default.
*
* @author <a href="mailto:tom.elrod@jboss.com">Tom Elrod</a>
*/
public class TransporterClient implements InvocationHandler, Serializable
{
private Client remotingClient = null;
private boolean isClustered = false;
private String subSystem = null;
private final Logger log = Logger.getLogger(TransporterClient.class);
// detector variables (only needed when clustering)
private static MBeanServer server = null;
private static Detector detector = null;
private static NetworkRegistry registry = null;
/**
* Creates the remoting client to server POJO.
* Is not clustered.
*
* @param locator
* @throws Exception
*/
private TransporterClient(InvokerLocator locator) throws Exception
{
remotingClient = new Client(locator);
remotingClient.connect();
}
/**
* Creates the remoting client to server POJO.
* Is clustered
*
* @param locator
* @param targetSubsystem
* @throws Exception
*/
private TransporterClient(InvokerLocator locator, String targetSubsystem) throws Exception
{
this(locator);
this.isClustered = true;
this.subSystem = targetSubsystem;
}
/**
* Disconnects the remoting client
*/
private void disconnect()
{
if(remotingClient != null)
{
remotingClient.disconnect();
}
}
/**
* Will set up network registry and detector for clustering (to identify other
* remoting servers running on network).
*
* @throws Exception
*/
private static void setupDetector() throws Exception
{
server = MBeanServerFactory.createMBeanServer();
// the registry will house all remoting servers discovered
registry = NetworkRegistry.getInstance();
server.registerMBean(registry, new ObjectName("remoting:type=NetworkRegistry"));
// multicast detector will detect new network registries that come online
detector = new MulticastDetector();
server.registerMBean(detector, new ObjectName("remoting:type=MulticastDetector"));
detector.start();
}
/**
* Create a remote proxy to a POJO on a remote server.
*
* @param locatorURI - the remoting locator uri to the target server where the target POJO exists.
* @param targetClass - the interface class of the POJO will be calling upon.
* @param clustered - true will cause the transporter to look for other remoting serves that have the POJO running
* and include it in the client's target list. If a call on first target fails, will seamlessly fail over to one
* of the other discovered targets.
* @return dynamic remote proxy typed to the interface specified by the targetClass param.
* @throws Exception
*/
public static Object createTransporterClient(String locatorURI, Class targetClass, boolean clustered) throws Exception
{
if(!clustered)
{
return createTransporterClient(locatorURI, targetClass);
}
else
{
if(registry == null)
{
setupDetector();
}
InvokerLocator locator = new InvokerLocator(locatorURI);
TransporterClient client = new TransporterClient(locator, targetClass.getName());
return Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(),
new Class[]{targetClass}, client);
}
}
/**
* Create a remote proxy to a POJO on a remote server.
*
* @param locatorURI - the remoting locator uri to the target server where the target POJO exists.
* @param targetClass - the interface class of the POJO will be calling upon.
* @return dynamic remote proxy typed to the interface specified by the targetClass param.
* @throws Exception
*/
public static Object createTransporterClient(String locatorURI, Class targetClass) throws Exception
{
InvokerLocator locator = new InvokerLocator(locatorURI);
return createTransporterClient(locator, targetClass);
}
/**
* Create a remote proxy to a POJO on a remote server.
*
* @param locator - the remoting locator to the target server where the target POJO exists.
* @param targetClass - the interface class of the POJO will be calling upon.
* @return dynamic remote proxy typed to the interface specified by the targetClass param.
* @throws Exception
*/
public static Object createTransporterClient(InvokerLocator locator, Class targetClass) throws Exception
{
TransporterClient client = new TransporterClient(locator);
return Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(),
new Class[]{targetClass}, client);
}
/**
* Needs to be called by user when no longer need to make calls on remote POJO. Otherwise will
* maintain remote connection until this is called.
*
* @param transporterClient
*/
public static void destroyTransporterClient(Object transporterClient)
{
if(transporterClient instanceof Proxy)
{
InvocationHandler handler = Proxy.getInvocationHandler(transporterClient);
if(handler instanceof TransporterClient)
{
TransporterClient client = (TransporterClient) handler;
client.disconnect();
}
else
{
throw new IllegalArgumentException("Object is not a transporter client.");
}
}
else
{
throw new IllegalArgumentException("Object is not a transporter client.");
}
}
/**
* The method called when anyone calls on the dynamic proxy returned by getProcessor().
* This method will simply convert the proxy call info into a remoting invocation on the
* target remoting server (using a NameBaseInvocation).
*
* @param proxy
* @param method
* @param args
* @return
* @throws Throwable
*/
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable
{
String methodName = method.getName();
String[] paramSig = createParamSignature(method.getParameterTypes());
NameBasedInvocation request = new NameBasedInvocation(methodName,
args,
paramSig);
Object response = null;
boolean failOver = false;
do
{
try
{
failOver = false;
response = remotingClient.invoke(request);
}
catch(CannotConnectException cnc)
{
failOver = findAlternativeTarget();
if(!failOver)
{
throw cnc;
}
}
catch(InvocationTargetException itex)
{
Throwable rootEx = itex.getCause();
throw rootEx;
}
}
while(failOver);
return response;
}
/**
* Will check to see if the network registry has found any other remoting servers. Then will check
* to see if any of them contain the subsystem we are interested in (which will corespond to the proxy type we
* are using). If one is found, will try to create a remoting client and connect to it.
* If can't find one, will return fasle.
*
* @return
*/
private boolean findAlternativeTarget()
{
boolean failover = false;
if(registry != null)
{
NetworkInstance[] instances = registry.getServers();
if(instances != null)
{
for(int x = 0; x < instances.length; x++)
{
NetworkInstance netInstance = instances[x];
ServerInvokerMetadata[] metadata = netInstance.getServerInvokers();
for(int i = 0; i < metadata.length; i++)
{
ServerInvokerMetadata data = metadata[i];
String[] subsystems = data.getSubSystems();
for(int z = 0; z < subsystems.length; z++)
{
if(subSystem.equalsIgnoreCase(subsystems[z]))
{
// finally found server with target handler
InvokerLocator newLocator = data.getInvokerLocator();
if(!remotingClient.getInvoker().getLocator().equals(newLocator))
{
try
{
remotingClient = new Client(newLocator);
remotingClient.connect();
return true;
}
catch(Exception e)
{
log.warn("Problem connecting to newly found alternate target.", e);
}
}
}
}
}
}
}
}
return failover;
}
/**
* Converts the Class array supplied via the dynamic proxy to
* a String array of the respective class names, which is need by
* the NameBasedInvocation object.
*
* @param args
* @return
*/
private String[] createParamSignature(Class[] args)
{
if(args == null || args.length == 0)
{
return new String[]{};
}
String[] paramSig = new String[args.length];
for(int x = 0; x < args.length; x++)
{
paramSig[x] = args[x].getName();
}
return paramSig;
}
}