Penggunaan Record Comparator pada Mobile

Pengurutan sebuah enumerasi dapat didefinisikan menggunakan sebuah Record Comparator. Record comparatr dapat digunakan melalui method enumerateRecords.

Inilah contoh scriptnya :



import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.rms.*;
import java.io.*;

public class RMSComparator extends MIDlet implements CommandListener,RecordComparator
{
    Display display;
    List recList;
    RecordStore recStore;
    byte[] data = null;
    Command exitCommand = new Command("Exit", Command.EXIT, 1);
    Command newCommand = new Command("New Item", Command.OK, 1);
    Ticker ticker = new Ticker("JENI - Java Education Network Indonesia");
    public RMSComparator()
    {
        recList = new List("Record List",List.IMPLICIT);
        dispRec();
        recList.setTicker(ticker);
        recList.addCommand(exitCommand);
        recList.addCommand(newCommand);
        recList.setCommandListener(this);
    }
    public void startApp()
    {
        if (display == null)
        {
            display = Display.getDisplay(this);
            display.setCurrent(recList);
        }
    }
    public void pauseApp(){
    }
    public void destroyApp(boolean unconditional) {
    }
    public void commandAction(Command c, Displayable d)
    {
        if (c== exitCommand)
        {
            destroyApp(true);
            notifyDestroyed();// Exit
        }
        if (c== newCommand)
        {
            try
            {
                recStore= RecordStore.openRecordStore("RmsComparator", true);
                ByteArrayOutputStream out = new ByteArrayOutputStream();
                DataOutputStream dOut= new DataOutputStream(out);
                dOut.writeInt(recStore.getNextRecordID()* recStore.getNextRecordID());
                dOut.writeUTF("Record #" + recStore.getNextRecordID());
                byte[] bytes = out.toByteArray();
                recStore.addRecord(bytes,0,bytes.length);
                dOut.close();
                out.close();
                recStore.closeRecordStore();
            }catch(Exception e)
            {
                System.out.println(e.toString());
            }
            dispRec();
        }
    }
    public void dispRec()
    {
        recList.deleteAll();
        try
        {
            recStore= RecordStore.openRecordStore("RmsComparator", true);
            RecordEnumeration enumerator
            = recStore.enumerateRecords(null, this, false);
            while (enumerator.hasNextElement())
            {
                byte[] recBytes = enumerator.nextRecord();
                ByteArrayInputStream in = new ByteArrayInputStream(recBytes);
                DataInputStream dIn = new DataInputStream(in);
                int count=dIn.readInt();
                String item = dIn.readUTF();
                recList.append(count+","+item,null);
                dIn.close();
                in.close();
            }
            recStore.closeRecordStore();
        }catch (Exception e)
        {
        }
    }
    public int compare(byte[] rec1, byte[] rec2)
    {
        String record1 = new String(rec1).toUpperCase();
        String record2 = new String(rec2).toUpperCase();
        if (record1.compareTo(record2) < 0)
        {
            return(PRECEDES);
        } else
        {
            if (record1.compareTo(record2) > 0)
            {
                return(FOLLOWS);
            } else
            {
                return(EQUIVALENT);
            }
        }
    }
}

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