JoystickInterface.java

/*
 *  Player Java Client 3 - JoystickInterface.java
 *  Copyright (C) 2002-2006 Radu Bogdan Rusu, Maxim Batalin
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * $Id$
 *
 */
package javaclient3;

import java.io.IOException;


import javaclient3.structures.PlayerMsgHdr;
import javaclient3.structures.joystick.PlayerJoystickData;
import javaclient3.xdr.OncRpcException;
import javaclient3.xdr.XdrBufferDecodingStream;

/**
 * The joystick interface provides access to the state of a joystick. It allows 
 * another driver or a (possibly off-board) client to read and use the state of a joystick.\
 * <br>
 * This interface accepts no commands or configuration requests.
 * @author Radu Bogdan Rusu
 * @version
 * <ul>
 *      <li>v2.0 - Player 2.0 supported
 * </ul>
 */
public class JoystickInterface extends PlayerDevice {
    
    private PlayerJoystickData pjdata;
    private boolean            readyPjdata = false;
    
    /**
     * Constructor for JoystickInterface.
     * @param pc a reference to the PlayerClient object
     */
    public JoystickInterface (PlayerClient pc) { super(pc); }
    
    /**
     * The joystick data packet, which contains the current state of the joystick.
     */
    public synchronized void readData (PlayerMsgHdr header) {
        try {
            switch (header.getSubtype ()) {
                case PLAYER_JOYSTICK_DATA_STATE: {
                    this.timestamp = header.getTimestamp();
               
                    pjdata = new PlayerJoystickData ();
                    
                    // Buffer for reading xpos, ypos, xscale, yscale, buttons
                    byte[] buffer = new byte[20];
                    // Read xpos, ypos, xscale, yscale, buttons
                    is.readFully (buffer, 0, 20);
                    
                    // Begin decoding the XDR buffer
                    XdrBufferDecodingStream xdr = new XdrBufferDecodingStream (buffer);
                    xdr.beginDecoding ();
                    pjdata.setXpos    (xdr.xdrDecodeInt ());
                    pjdata.setYpos    (xdr.xdrDecodeInt ()); 
                    pjdata.setXscale  (xdr.xdrDecodeInt ());
                    pjdata.setYscale  (xdr.xdrDecodeInt ());
                    pjdata.setButtons (xdr.xdrDecodeInt ());
                    xdr.endDecoding   ();
                    xdr.close ();
                    
                    readyPjdata = true;
                    break;
                }
            }
        } catch (IOException e) {
            throw new PlayerException 
                ("[Joystick] : Error reading payload: " + 
                        e.toString(), e);
        } catch (OncRpcException e) {
            throw new PlayerException 
                ("[Joystick] : Error while XDR-decoding payload: " + 
                        e.toString(), e);
        }
    }

    /**
     * Returns the joystick data (xpos, ypos, xscale, yscale, buttons)
     * @return the joystick data
     */
    public synchronized PlayerJoystickData getData () { return pjdata; }
    
    /**
     * Check if data is available.
     * @return true if ready, false if not ready 
     */
    public boolean isDataReady () {
        if (readyPjdata) {
            readyPjdata = false;
            return true;
        }
        return false;
    }
}