LocalNetworkModule.java

/* 
 * Copyright (c) 2009, 2012 IBM Corp.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    Dave Locke - initial API and implementation and/or initial documentation
 */
package org.eclipse.paho.client.mqttv3.internal;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.Method;

import org.eclipse.paho.client.mqttv3.MqttException;


/**
 * Special comms class that allows an MQTT client to use a non TCP / optimised 
 * mechanism to talk to an MQTT server when running in the same JRE instance as the 
 * MQTT server.  
 *
 * This class checks for the existence of the optimised comms adatper class i.e. the one
 * that provides the optimised communication mechanism.  If not available the request
 * to connect using the optimised mechanism is rejected.  
 *  
 * The only known server that implements this is the microbroker:- an MQTT server that 
 * ships with a number of IBM products.
 */
public class LocalNetworkModule implements NetworkModule {
	private Class LocalListener;
	private String brokerName;
	private Object localAdapter;
	
	public LocalNetworkModule(String brokerName) {
		this.brokerName = brokerName;
	}

	public void start() throws IOException, MqttException{
		if (!ExceptionHelper.isClassAvailable("com.ibm.mqttdirect.modules.local.bindings.LocalListener")) {
			throw ExceptionHelper.createMqttException(MqttException.REASON_CODE_SERVER_CONNECT_ERROR);
		}
		try {
			LocalListener = Class.forName("com.ibm.mqttdirect.modules.local.bindings.LocalListener");
			Method connect_m = LocalListener.getMethod("connect", new Class[]{ java.lang.String.class });
			localAdapter = connect_m.invoke(null,new Object[]{ brokerName });
		} catch(Exception e) {
		}
		if(localAdapter == null) {
			throw ExceptionHelper.createMqttException(MqttException.REASON_CODE_SERVER_CONNECT_ERROR);
		}
	}

	public InputStream getInputStream() throws IOException {
		InputStream stream = null;
		try {
			Method m = LocalListener.getMethod("getClientInputStream",new Class[]{});
			stream = (InputStream)m.invoke(this.localAdapter,new Object[]{});
		} catch(Exception e) {
		}
		return stream;
	}
	
	public OutputStream getOutputStream() throws IOException {
		OutputStream stream = null;
		try {
			Method m = LocalListener.getMethod("getClientOutputStream",new Class[]{});
			stream = (OutputStream)m.invoke(this.localAdapter,new Object[]{});
		} catch(Exception e) {
		}
		return stream;
	}

	public void stop() throws IOException {
		if (localAdapter != null) {
			try {
				Method m = LocalListener.getMethod("close",new Class[]{});
				m.invoke(this.localAdapter,new Object[]{});
			} catch(Exception e) {
			}
		}
	}
}