//
// (C) COPYRIGHT International Business Machines Corp. 1997
// All Rights Reserved
// Licensed Materials - Property of IBM
//
// US Government Users Restricted Rights - Use, duplication or
// disclosure restricted by GSA ADP Schedule Contract with IBM Corp.
//


/*
 * $Header: /home/gda/dxcvs/dx/src/ui++/java/dx/server/DXThread.java,v 1.1.1.1 1999/03/24 15:17:33 gda Exp $
 */
import java.net.*;
import java.io.*;
import java.util.*;
import dx.protocol.*;

public abstract class DXThread extends Thread
{
    protected Socket clientSocket = null;
    protected Vector actions;

    private DataInputStream is;
    private PrintStream os;
    private Vector msg_queue;

    //
    // Failure status
    //
    private boolean failed = false;
    protected void setFailed() { failed = true; }
    protected boolean isFailed() { return failed; }

    //
    // debug status
    //
    private boolean debug = false;
    protected boolean isDebug() { return debug; }

    public void cleanUp() { }


protected DXThread (Socket client)
{
    clientSocket = client;
    try {
	InputStream bis = new DataInputStream(clientSocket.getInputStream());
	OutputStream bos = new DataOutputStream(clientSocket.getOutputStream());
	is = new DataInputStream(bis);
	os = new PrintStream(bos, false);
    } catch (Exception e) {
	e.printStackTrace();
	is = null;
	os = null;
    }

    actions = new Vector(20);
    msg_queue = new Vector(10);

    String debug_option_string = getClass().getName() + ".debug";
    String dbgmsgs = System.getProperty(debug_option_string);
    if (dbgmsgs != null) debug = true;
    else debug = false;
    failed = false;
}

protected String getNextString() throws IOException
{
    String retval = null;
    synchronized(msg_queue) {
	if (getQueueSize() > 0) {
	    String msg = (String)msg_queue.firstElement();
	    msg_queue.removeElementAt(0);
	    retval = msg;
	} else
	    retval = is.readLine();
    }
    return retval;
}

protected int getQueueSize() throws IOException
{
    int qsize = 0;
    synchronized (msg_queue) {
	while (is.available() > 0) {
	    String inputLine = is.readLine();
	    msg_queue.addElement((Object)inputLine);
	}
	qsize = msg_queue.size();
    }
    return qsize;
}

public final void run()
{
    String inputLine = null;
    try {
	while ((failed == false) && ((inputLine = getNextString()) != null)) {
	    if (debug)
		System.out.println (getName()+": " + inputLine);
	    Enumeration enum = actions.elements();
	    boolean executed = false;
	    while (enum.hasMoreElements()) {
		DXThreadCommand stc = (DXThreadCommand)enum.nextElement();
		if (inputLine.startsWith(stc.getCommandString())) {
		    executed = stc.execute(inputLine);
		    if (executed) break;
		}
	    }
	    if (!executed)
		System.out.println (getName() + ": Unrecognized: " +
		    inputLine);
	}
    } catch (SocketException se) {
    } catch (Exception e) {
	e.printStackTrace();
	setFailed();
    }
    disconnect();
}

protected void transmit(threadMsg msg)
{
    if (isDebug()) {
	System.out.println ("                                       " +
	    getName() + ": " + msg.toString());
    }

    os.println (msg.toString());
    os.flush();
}

//
// There's a problem here I don't understand.  The thread is generally sitting
// in getNextString() waiting for input from the browser.  If DXServer decides
// it's time to shutdown, then he wants to call disconnect() for every running
// thread.  The problem with that is that the call to close a socket blocks.
// I don't know why - must have something to do with having a thread inside
// readLine.  The book says these methods aren't synchronized but apparently
// something is synchronized inside there.  So, I wrote virtual cleanUp() 
// so that DXServer can call run clean-up type work before shutting down.
// That's important because we need a change to erase image files.
//
protected boolean disconnect(threadMsg msg)
{
    cleanUp();
    try { clientSocket.close(); } catch (Exception e) { }
    try { is.close(); } catch (Exception e) { }
    try { os.close(); } catch (Exception e) { }
    return true;
}

protected boolean disconnect() { return disconnect(null); }

protected String peekQueue(String cmd, boolean remove) throws IOException
{
    String retval = null;
    synchronized (msg_queue) {
	if (getQueueSize() > 0) {
	    Enumeration enum = msg_queue.elements();
	    while (enum.hasMoreElements()) {
		String msg = (String)enum.nextElement();
		if (msg.startsWith(cmd)) {
		    retval = msg;
		    break;
		}
	    }
	    if (remove) 
		msg_queue.removeElement(retval);
	}
    }
    return retval;
}


} // end DXThread