基于MIDP1.0实现RMS容量探测器

作者：mingjava  文章来源：http://www.j2medev.com/Article/ShowArticle.asp?ArticleID=68

软件名称：RMS容量探测器
    作者简介：詹建飞(mingjava)，北京邮电大学信息工程学院信号与信息处理专业研究生。
    电子信箱：[e-mail]

    之所以写这个RMS容量探测器是因为我在nokia 6108手机上编写个人通信录的时候想知道它的RecordStore最大有多少空间可以使用。我调用getSizeAviable()的时候发现它返回的值几乎等于手机上剩余的内存空间的值，因此我想这个API的实现是错误的。于是编写了这个简单的RMS容量探测器，它能探测手机上一个RecordStore能存储数据的最大值，单位是K字节,请不要在模拟器上运行这个软件，这没有任何意义。下面简单介绍一下实现。

    由于软件比较小，因此我没有应用MVC的设计模式，如果编写较大的应用程序一定要使用MVC。软件一共有三个类:CounterCanvas,RMSAnalyzer和RMSModel。软件的原理是：新建一个RecordStore然后每隔100ms往里面写入1K的数据，在退出的时候删除这个RecordStore。思路非常简单！代码也不复杂，因此我直接给出源代码。你可以从这里下载源文件(其中包括jar文件和jad文件)。如果提供下载请注明出处和作者

import javax.microedition.rms.*;
public class RMSModel
{
    public static final int K = 1024;
    private RecordStore rs;
    private int baseCount;
    private RMSAnalyzer RMSanalyzer;
    public static final String name = "test";

    public RMSModel(int baseCount, RMSAnalyzer rmsa)
            throws RecordStoreException
    {
        this.baseCount = baseCount;
        this.RMSanalyzer = rmsa;
        if (rs == null)
        {
            rs = RecordStore.openRecordStore(name, true);
            writeRecord(baseCount);
        }
    }

    public void writeRecord(int count) throws RecordStoreException
    {
        byte[] data = new byte[count * K];
        for (int i = 0; i < count; i++)
        {
            data[i] = 1;
        }
        rs.addRecord(data, 0, count * K);
    }

    public void deleteRMS()
    {
        try
        {
            rs.closeRecordStore();
            RecordStore.deleteRecordStore(name);
        } catch (RecordStoreException e)
        {
            RMSanalyzer.showAlertError(e.getMessage());
        }
    }
}

import java.io.IOException;

import javax.microedition.lcdui.Alert;
import javax.microedition.lcdui.AlertType;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.Image;
import javax.microedition.midlet.MIDlet;
import javax.microedition.midlet.MIDletStateChangeException;
import javax.microedition.rms.RecordStoreException;

public class RMSAnalyzer extends MIDlet implements CommandListener
{

    private Display display;
    private CounterCanvas counterCanvas;
    private Alert alert;
    public static final Command startCommand = new Command("开始", Command.ITEM,
            1);
    public static final Command exitCommand = new Command("退出", Command.EXIT, 2);

    protected void startApp() throws MIDletStateChangeException
    {

        display = Display.getDisplay(this);
        alert = new Alert("错误提示");
        try
        {
            String interval = this.getAppProperty("INTER");
            int t = Integer.parseInt(interval);
            counterCanvas = new CounterCanvas(t, 0, this);
        } catch (RecordStoreException e)
        {
            this.showAlertError(e.getMessage());
        }
        Form mainForm = new Form("RMS测试器");
        Image mainImage = getMainImage("java.png");
        if (mainImage != null)
        {
            mainForm.append(mainImage);
        } else
        {
            mainForm.append("欢迎使用自由软件");
        }
        mainForm.addCommand(startCommand);
        mainForm.addCommand(exitCommand);
        mainForm.setCommandListener(this);
        display.setCurrent(mainForm);

    }

    public Image getMainImage(String name)
    {
        Image image = null;
        try
        {
            image = Image.createImage("/" + name);
        } catch (IOException e)
        {
            return null;
        }
        return image;
    }

    public Display getDisplay()
    {
        return display;
    }

    protected void pauseApp()
    {
      

    }

    protected void destroyApp(boolean arg0) throws MIDletStateChangeException
    {
    

    }

    public void commandAction(Command cmd, Displayable disp)
    {
        if (cmd == startCommand)
        {
            display.setCurrent(counterCanvas);
            counterCanvas.start();
        } else if (cmd == exitCommand)
        {
            exitMIDlet();
        }
    }

    public void exitMIDlet()
    {
        try
        {
            destroyApp(false);
            notifyDestroyed();
        } catch (MIDletStateChangeException e)
        {
            showAlertError(e.getMessage());
        }
    }

    public void showAlertError(String message)
    {
        alert.setString(message);
        alert.setType(AlertType.ERROR);
        alert.setTimeout(2500);
        display.setCurrent(alert);

    }

}

import java.util.Timer;
import java.util.TimerTask;

import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Graphics;
import javax.microedition.rms.*;

public class CounterCanvas extends Canvas implements CommandListener
{

    private RMSModel model;
    private RMSAnalyzer RMSanalyzer;
    private int interTime;
    private int counter;
    private boolean go = true;
    public static Command exitCommand = new Command("退出", Command.EXIT, 3);
    public static final int INC = 1;
    public TimerTask timerTask;
    public final Timer timer = new Timer();

public CounterCanvas(int interTime, int base, RMSAnalyzer rmsa)
            throws RecordStoreException
    {
        this.interTime = interTime;
        this.counter = base;
        this.RMSanalyzer = rmsa;
        model = new RMSModel(base, RMSanalyzer);
        this.addCommand(exitCommand);
        this.setCommandListener(this);

        timerTask = new TimerTask()
        {
            public void run()
            {

                try
                {
                    model.writeRecord(INC);
                    counter++;
                } catch (RecordStoreFullException e)
                {
                    go = false;
                    model.deleteRMS();
                    timer.cancel();
                } catch (RecordStoreException e)
                {
                    model.deleteRMS();
                    RMSanalyzer.showAlertError(e.getMessage());
                    timer.cancel();
                }
                repaint();

            }
        };

    }

    public void start()
    {
        timer.schedule(timerTask, 500, interTime);
    }

    public void setCounter(int counter)
    {
        this.counter = counter;
    }

    public void setInterTime(int interTime)
    {
        this.interTime = interTime;
    }

    protected void paint(Graphics arg0)
    {
       
        int SCREEN_WIDTH = this.getWidth();
        int SCREEN_HEIGHT = this.getHeight();
        arg0.drawRect(SCREEN_WIDTH / 10, SCREEN_HEIGHT / 2,
                SCREEN_WIDTH * 4 / 5, 10);
        if (RMSanalyzer.getDisplay().isColor())
        {
            arg0.setColor(128, 128, 255);
        }
        arg0.fillRect(SCREEN_WIDTH / 10 + 1, SCREEN_HEIGHT / 2 + 1, counter, 9);
        if (!go)
            arg0.drawString("最大值:" + counter + "K字节", SCREEN_WIDTH / 10,
                    SCREEN_HEIGHT / 10, Graphics.TOP | Graphics.LEFT);

    }

    public void commandAction(Command arg0, Displayable arg1)
    {
       
        if (arg0 == exitCommand)
        {
            RMSanalyzer.exitMIDlet();
        }

    }

}
RMSAnalyzer.jad
MIDlet-Jar-Size: 15785
MIDlet-1: RMSAnalyzer,,RMSAnalyzer
MIDlet-Jar-URL: RMSAnalyzer.jar
MicroEdition-Configuration: CLDC-1.0
MIDlet-Version: 1.0.0
MIDlet-Name: RMSAnalyzer
MIDlet-Data-Size: 8192
MIDlet-Vendor: www.j2medev.com
MicroEdition-Profile: MIDP-1.0
INTER: 100