btconnection.java

p2p仿真

/*
 * @(#)BTConnection.java	ver 1.2  6/20/2005
 *
 * Copyright 2005 Weishuai Yang ([e-mail]). 
 * All rights reserved.
 * 
 */
 
package gps.protocol.BT;

import gps.network.Connection;


/**
 * two way connection between two BTSockets.
 *
 *
 * @author  Weishuai Yang
 * @version 1.2,  6/20/2005
 */

public class BTConnection extends Connection {
    /**
     * source bt socket
     */
	private BTSocket mSource;
    /**
     * destination bt socket
     */
	private BTSocket mDestination;
	
	/**
	 * constructs BTConnection object
	 * @param a source BTSocket
	 * @param b destination BTSocket
	 */
	public BTConnection(BTSocket a, BTSocket b){
		super(a.mSession.getAgent(),b.mSession.getAgent());
		mSource=a;
		mDestination=b;
	}

	/**
	 * get bandwidth for the flow origniated from a BTSocket
	 * @param s source BTSocket
	 * @return one way bandwidth
	 */
	public double getBandwidthFrom(BTSocket s){
		return super.getBandwidthFrom(s.mSession.getAgent().getNode());
	}
	/**
	 * set bandwidth for the flow origniated from a BTSocket
	 * @param s source BTSocket
	 * @param b new bandwidth
	 */
	public void setBandwidthFrom(BTSocket s, double b){
		super.setBandwidthFrom(s.mSession.getAgent().getNode(), b);
	}
	
	/**
	 * request more or less bandwidth for a connection
	 * @param adj adjustment
	 */
	public void adjustBandwidth(double adj){
		super.adjustBandwidth(adj);
		//bandwidth is already changed here.
		
		if(mSource.mDownloading&&mDestination.mDownloading){
			mBandwidthAtoB=mBandwidth/2;
			mBandwidthBtoA=mBandwidth/2;
			mSource.adjustInBandwidth(adj/2);
			mDestination.adjustOutBandwidth(adj/2);
			mSource.adjustInBandwidth(adj/2);
			mDestination.adjustOutBandwidth(adj/2);
		}
		else if(mSource.mDownloading&&!mDestination.mDownloading){
			mBandwidthAtoB=0;
			mBandwidthBtoA=mBandwidth;
			mSource.adjustInBandwidth(adj);
			mDestination.adjustOutBandwidth(adj);
		}
		else if(!mSource.mDownloading&&mDestination.mDownloading){
			mBandwidthAtoB=mBandwidth;
			mBandwidthBtoA=0;
			mSource.adjustOutBandwidth(adj);
			mDestination.adjustInBandwidth(adj);
		}
	}
	
	/**
	 * gets string description
	 * @return string description
	 */
	public String toString() {
		String ret = "Connection("+mSource+"->"+mDestination+")";
		if (mActive) 
			ret += ": Active, Bandwidth: "+mBandwidth;
		else 
			ret += ": InActive";
		ret+=" ";
		return ret;
	}
}