receiver_01.java

codigo fuente de protocolo ARQ stop and wait (IDLE ARQ)

package ece544.p1.zbwu;

import java.io.IOException;
import java.io.OutputStream;

import ece544.p1.IReceiver;
import edu.rutgers.winlab.labloma.net.*;


/**
 * Jan 28, 2003
 * This is for implementation of IReceiver, the
 * receiver is going to recieved fix-length packets of 1024
 * while the last 4 bytes is an length indicator.
 * Thus, 1020 data bytes + 4 length indicator
 
 * @author Zhibin Wu 
 */
public class 
Receiver 
	implements IReceiver 
{

	/**
	 * the parameter addr is not used,
         * define private member varibles here
         * out is the buffer to store the packet , then the data in
         * the packet will be send to the outputstream after length indicator
         * is evaluated
	 */
        private INetworkPort defaultport;
        private byte[] out;

	public 
	Receiver(
		INetworkPort port, 
		IAddress addr
	) {
             defaultport = port ;
             out = new byte[1024];
            
	}

	/**
	 * @see ece544.p1.IReceiver#receive(OutputStream)
         *
         * The method is simple, reading a packet of 1024, see last 4 bytes to
         * parse the length as an integer "len_rcvd",
         * then sending the number of bytes as data to outputstream  
         *
	 */
	public void 
	receive(
		OutputStream stream
	) throws IOException
	{


            int i;
            int len_rcvd;
            
            
            do
            {
                 defaultport.recv(out);
                 String s = new String(out,1020, 4);
	         len_rcvd = Integer.parseInt(s);
           	 stream.write (out,0,len_rcvd);
              
            } while (defaultport.hasMore());
                        

          
	}

}