jadex.base.relay.JadexRelayExample Maven / Gradle / Ivy

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Base classes for Jadex relay server.
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package jadex.base.relay;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.Random;


/**
 *  Example showing how to connect to Jadex relay server using pure Java only
 *  (no Jadex jars required).
 *  It is recommended using the helper methods of RelayConnectionManager instead. 
 */
public class JadexRelayExample
{
	//-------- example code below --------
	
	/**
	 *  Main method for testing.
	 */
	public static void	main(String[] args)	throws Exception
	{
		// Create a random id, which is used for sending message to.
		String	id	= "RelayExample_"+new Random().nextInt(1000);
		
		// Connect to server (starts receiver thread in background).
		connect(id);
		
		// Send a message to self.
		send(id, "Hello Relay World!".getBytes("UTF-8"));

		send(id, "some more testing...".getBytes("UTF-8"));

		// Wait while received message is printed on receiver thread.
		Thread.sleep(1000);
		
		// Exit
		System.exit(0);
	}
	
	/**
	 *  Called whenever a message is received.
	 */
	public static void	deliverMessage(byte[] rawmsg)
	{
		try
		{
			System.out.println("Message received: "+new String(rawmsg, "UTF-8"));
		}
		catch (UnsupportedEncodingException e)
		{
			throw new RuntimeException(e);
		}
	}
	
	//-------- helper code below (need not be touched) --------
	
	/** The relay server address. */
	public static final String	ADDRESS	= "http://www.activecomponents.org/relay/";
	
	/** The default message type: followed by length (int as 4 bytes) and arbitrary message content from some sender. */
	public static final byte	MSGTYPE_DEFAULT	= 1;
	
	/** The ping message type sent by server to verify if connection is alive (just the type byte and no content). */
	public static final byte	MSGTYPE_PING	= 2;
	
	/**
	 *  Start a new thread and connect to the relay server. 
	 */
	public static void	connect(String id)	throws Exception
	{
		// Connect to server.
		URL	url	= new URL(ADDRESS+"?id="+URLEncoder.encode(id, "UTF-8"));
		HttpURLConnection	con	= (HttpURLConnection)url.openConnection();
		con.setUseCaches(false);
		final InputStream	in	= con.getInputStream();
		int read;
		while((read=in.read())!=-1 && read!=MSGTYPE_PING)
		{
			// wait for first ping.
			System.out.println(read);
		}
		
		// Start receiver thread.
		new Thread(new Runnable()
		{
			public void run()
			{
				try
				{
					while(true)
					{
						// Read message type.
						int	b	= in.read();
						if(b==-1)
						{
							throw new IOException("Stream closed");
						}
						else if(b==MSGTYPE_PING)
						{
							System.out.println("Received server ping");
						}
						else if(b==MSGTYPE_DEFAULT)
						{
							byte[] rawmsg	= null;
							
							// Read message header (size)
							int msg_size;
							byte[] asize = new byte[4];
							for(int i=0; i0)
							{
								rawmsg = new byte[msg_size];
								int count = 0;
								while(count>> 24) & 0xFF);
		buffer[1] = (byte)((val >>> 16) & 0xFF);
		buffer[2] = (byte)((val >>> 8) & 0xFF);
		buffer[3] = (byte)(val & 0xFF);

		return buffer;
	}
}