/* 
 * XClient.java --
 *
 * Copyright 1996 Regents of the University of California
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for any purpose and without
 * fee is hereby granted, provided that this copyright
 * notice appears in all copies.  The University of California
 * makes no representations about the suitability of this
 * software for any purpose.  It is provided "as is" without
 * express or implied warranty.
 *
 * rcsid = "$Header: /disks/barad-dur/now/rywang/src/java/classes/ryw/XAnim.java,v 1.1 1995/10/07 14:15:40 rywang Exp $ xFS (Berkeley)"
 */

package ryw;

import java.lang.*;
import java.net.*;
import java.io.*;


/**
 * A client object that connects, reads, and writes from a server
 * in a thread.
 */
public abstract class XClient implements Runnable {
    String host;
    int port;
    int retryInter;
    Thread listener;
    Socket server;
    protected InputStream ins;
    protected OutputStream outs;
    protected DataInputStream dins;
    protected DataOutputStream douts;
    protected PrintStream pouts;
    protected boolean connected;

    
    public synchronized void connect (String host, int port)
	throws IOException {
	XError.info ("XClient:connect:to "+host+" at "+port);
	this.host = host;
	this.port = port;
	stop ();
	server = new Socket (host, port);
	ins = server.getInputStream ();
	dins = new DataInputStream (ins);
	outs = server.getOutputStream ();
	douts = new DataOutputStream (outs);
	pouts = new PrintStream (outs);
	connected = true;
	start ();
	XError.info ("XClient:connection established");
    }


    public synchronized void reset () {
	try {
	    if (server != null) {
		server.close ();
		server = null;
	    }
	    connected = false;
	    if (ins != null) {
		ins.close ();
		ins = null;
		dins = null;
	    }
	    if (outs != null) {
		outs.close ();
		outs = null;
		douts = null;
	    }
	} catch (Exception e) {
	}
    }


    public synchronized void tryConnect (String host, int port,
					 int retryInter) {
	this.retryInter = retryInter;
	for (;;) {
	    try {
		connect (host, port);
		break;
	    } catch (Exception e) {
		XError.yell ("XClient:tryConnect: failed to connect");
		try {
		    Thread.sleep (retryInter);
		} catch (Exception e2) {
		}
		XError.info ("XClient:tryConnect: retrying...");
	    }
	}
    }


    public synchronized void tryReconnect () {
	tryConnect (host, port, retryInter);
    }
	    

    public synchronized void start () {
	if (listener == null) {
	    if (!connected)
		tryReconnect ();
	    listener = new Thread (this);
	    listener.start ();
	}
    }


    public synchronized void stop () {
	connected = false;
	if (listener == null) {
	    return;
	}
	listener.stop ();
	listener = null;
	reset ();
    }


    public void run () {
	for (;;) {
	    try {
		readFromServer ();
	    } catch (ThreadDeath e) {
		XError.say ("XClient:run: thread death");
		throw e;
	    } catch (IOException e) {
		if (connected) {
		    XError.yell (e, "XClient:run: readFromServer failed");
		    tryConnect (host, port, retryInter);
		}
	    } catch (NullPointerException e) {
		/*
		 * When I kill this thread, I'm supposed to
		 * get ThreadDeath, but instead I get
		 * NullPointer from readFromServer().
		 */
		XError.say ("XClient:run: null pointer, thread stopped");
		throw new ThreadDeath ();
	    }
	}
    }


    public synchronized void sendLoop () {
	for (;;) {
	    try {
		sendToServer ();
	    } catch (IOException e) {
		XError.yell (e, "XClient:sendLoop: sendToServer failed");
		tryConnect (host, port, retryInter);
	    }
	}
    }


    public abstract void readFromServer () throws IOException;
    public abstract void sendToServer   () throws IOException;
}