slugsmidlet.java

这是我编写的第一个J2ME程序

/*
 * Copyright (c) 2002, 2003 Sun Microsystems, Inc. All Rights Reserved.
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * - Redistribution of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * - Redistribution in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution.
 * Neither the name of Sun Microsystems, Inc., 'Java', 'Java'-based
 * names, or the names of contributors may be used to endorse or promote
 * products derived from this software without specific prior written
 * permission.
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
 * MIDROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
 * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
 * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
 * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
 * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
 * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * You acknowledge that this software is not designed, licensed or
 * intended for use in the design, construction, operation or maintenance
 * of any nuclear facility. $Id: SlugsMIDlet.java,v 1.1 2003/06/03 00:55:31 zull Exp $
 */
package com.sun.j2me.blueprints.slugs.client;

import com.sun.j2me.blueprints.slugs.shared.*;
import com.sun.j2me.blueprints.slugs.shared.Item;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import javax.microedition.midlet.MIDlet;
import javax.microedition.lcdui.*;
import javax.microedition.io.*;

/**
 * This class implements a generic multiplayer
 * client harness. The class of the actual
 * visualization component, as well as the
 * IP address for the server are read from
 * the midlet's descriptor file.
 * 
 * <p>
 * The error handling in this class is very
 * rudimentary. For a production quality game,
 * an error dialog needs to be presented to
 * the user when things go wrong.
 */
public class SlugsMIDlet extends MIDlet implements Runnable, EventClient, 
        CommandListener {
    private static final String SCREEN_CLASS = "ScreenClass";
    private static final String SERVER_IP = "ServerIP";
    private Command exit;
    private Screen screen;
    private DataInputStream in;
    private DataOutputStream out;
    private StreamConnection conn;
    private int frame_no;
    private Frame frame;
    private boolean done;

    /**
     * Start the application
     */
    public void startApp() {
        int player_id;

        player_id = 0;
        exit = new Command("Exit", Command.EXIT, 1);

        try {
            conn = 
                (StreamConnection) Connector.open("socket://" 
                                                  + getAppProperty(SERVER_IP) 
                                                  + ":" + Server.PORT);
            in = new DataInputStream(conn.openInputStream());
            out = new DataOutputStream(conn.openOutputStream());
        } catch (IOException e) {
            closeConnection();
            System.out.println("*** could not connect to server: " + e);
            destroyApp(true);
        } 

        frame = new Frame(null, 0, 0);
        frame_no = -1;

        try {
            Message msg = new Message(Message.ALL_FRAMES, Message.SIGNUP);

            msg.archive(out);
            System.out.println("sent sign-up msg");

            msg = Message.createFromStream(in);

            if (msg.getType() != Message.SIGNUP_ACK) {
                System.out.println("*** could not sign up: " + msg);
                destroyApp(true);
            } 

            player_id = msg.getBody()[0];

            System.out.println("received sign-up ack, id = " + player_id);
        } catch (IOException e) {
            System.out.println("*** could not sign up with server: " + e);
            destroyApp(true);
        } 

        try {
            screen = 
                (Screen) Class.forName(getAppProperty(SCREEN_CLASS)).newInstance();
        } catch (Exception e) {
            System.out.println("*** could not create screen: " + e);
            destroyApp(true);
        } 

        screen.initialize(this, player_id);
        screen.setCommandListener(this);
        screen.addCommand(exit);

        done = false;

        Thread thread = new Thread(this);

        thread.start();
        Display.getDisplay(this).setCurrent(screen);
    } 

    /**
     * Pause the application
     */
    public void pauseApp() {}

    private void closeConnection() {
        try {
            if (in != null) {
                in.close();
            } 

            if (out != null) {
                out.close();
            } 

            if (conn != null) {
                conn.close();
            } 
        } catch (IOException e) {
            System.out.println(e);
        } 
    } 

    /**
     * Destroy the application
     */
    public void destroyApp(boolean unc) {
        System.out.println("MidpTestClient.destroyApp()");

        Message msg = new Message(Message.ALL_FRAMES, Message.SIGNOFF);

        try {
            msg.archive(out);
        } catch (IOException e) { /* ignore */
        } 

        closeConnection();
        Display.getDisplay(this).setCurrent(null);
    } 

    /**
     * Handle soft button events
     */
    public void commandAction(Command cmd, Displayable s) {
        if (cmd == exit) {
            done = true;

            destroyApp(true);
            notifyDestroyed();
        } 
    } 

    /**
     * Handle status events from the visualization component
     */
    public void handleEvent(int id, int data) {
        Message msg;

        synchronized (this) {
            msg = new Message(frame_no, id, data);
        } 

        try {
            msg.archive(out);
        } catch (IOException e) {
            System.out.println("*** could not send message: " + msg);
        } 
    } 

    private void handleStatus(Message msg) {
        Item item;

        synchronized (this) {
            int id = msg.getFrameNumber();

            if (id != frame_no + 1) {
                System.out.println("+++ message id sequence broken:");
                System.out.println("+++ expected " + (frame_no + 1));
                System.out.println("+++ got      " + id);
                System.out.println();
            } 

            frame.initFromIntegerArray(msg.getBody());

            frame_no = id;
        } 

        for (int i = 0; i < frame.getItemCount(); i++) {
            item = frame.getItemAt(i);

            screen.update(item.getStatus(), item.getX(), item.getY());
        } 

        screen.repaint();
    } 

    private void handleError() {
        Message msg = new Message(frame_no, Message.SIGNOFF);

        try {
            msg.archive(out);
        } catch (IOException e) { /* ignore */
        } 
    } 

    private void handleUnknown(Message msg) {
        System.out.println("received unknown message: " + msg);
    } 

    /**
     * Main loop
     */
    public void run() {
        Message msg;

        while (!done) {
            try {
                msg = Message.createFromStream(in);
            } catch (IOException e) {
                System.out.println("cant read message from stream");

                continue;
            } 

            switch (msg.getType()) {

            case Message.SERVER_STATUS:
                handleStatus(msg);

                break;

            case Message.ERROR:
                handleError();

                break;

            default:
                handleUnknown(msg);

                break;
            }
        } 
    } 

}