Mencari/mem-filter data dalam record store pada JAVA (J2ME)

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import javax.microedition.rms.*;
import java.io.IOException;
       
public class DemoCariRecord extends MIDlet
  implements CommandListener {
   
  private Display display;
  private List list;
  private TextField tfCari;
  private RecordStore rs = null;
   
  private final Command cmdKeluar =
    new Command("Keluar", Command.EXIT, 1);
  private final Command cmdKembali =
    new Command("Kembali", Command.BACK, 1);
  private final Command cmdPencarian =
    new Command("Pencarian", Command.SCREEN, 1);
  private final Command cmdCari =
    new Command("Cari", Command.OK, 1);
   
  public DemoCariRecord() {
    display = Display.getDisplay(this);
    list = new List(null, Choice.IMPLICIT);
    list.addCommand(cmdKeluar);
    list.addCommand(cmdPencarian);
    list.setCommandListener(this);
      
    try {
      rs = RecordStore.openRecordStore("DBNama", true);
    } catch (RecordStoreException rse) {
      rse.printStackTrace();
    }
       
  }
   
  public void startApp() {
    try {
      if (rs.getNumRecords() < 1) {
        tambahData("Kiki");
        tambahData("Fira");
        tambahData("Dede");
        tambahData("Mira");
        tambahData("Aryo");
        tambahData("Dona");
      }
    } catch (RecordStoreException rse) {
      rse.printStackTrace();
    }
    tampilkanData(false);
    display.setCurrent(list);
  }
   
  public void pauseApp() {       
  }
   
  public void destroyApp(boolean unconditional) {       
  }
   
  public void commandAction(Command c, Displayable s) {
    if (c == cmdKeluar) {
      destroyApp(false);
      notifyDestroyed();
    } else if (c == cmdKembali) {
      display.setCurrent(list);
      tampilkanData(false);
    } else if (c == cmdPencarian) {
      Form form = new Form("Cari Nama");
      tfCari = new TextField("Masukkan karakter pertama", null,
                              1, TextField.ANY);
      form.append(tfCari);
      form.addCommand(cmdCari);
      form.addCommand(cmdKembali);
      form.setCommandListener(this);
      display.setCurrent(form);
    } else if (c == cmdCari) {
      tampilkanData(true);
    }
  }
   
  public void tambahData(String nama) {
    byte[] temp = null;
           
    try {
      ByteArrayOutputStream baos =
        new ByteArrayOutputStream();
      DataOutputStream dos = new DataOutputStream(baos);
      dos.writeUTF(nama);
      temp = baos.toByteArray();
    } catch (IOException ioe) {
      ioe.printStackTrace();
    }
     
    try {
      rs.addRecord(temp, 0, temp.length);
    } catch (RecordStoreNotOpenException rsnoe) {
      rsnoe.printStackTrace();
    } catch (RecordStoreException rse) {
      rse.printStackTrace();
    }
  }
   
  public void tampilkanData(boolean filter) {
    byte[] temp = null;
    RecordEnumeration re = null;

    list.deleteAll();
    try {           
      if (filter) {
        String s = tfCari.getString().toLowerCase();
        CariNama cn = new CariNama(s);
        re = rs.enumerateRecords(cn, null, false);
        list.setTitle("Hasil Pencarian");
        list.removeCommand(cmdPencarian);
        list.removeCommand(cmdKeluar);
        list.addCommand(cmdKembali);
      } else {
        re = rs.enumerateRecords(null, null, false);
        list.setTitle("Daftar Nama");
        list.addCommand(cmdPencarian);
        list.addCommand(cmdKeluar);
        list.removeCommand(cmdKembali);
      }
      while (re.hasNextElement()) {
        int i = re.nextRecordId();               
        temp = rs.getRecord(i);
        ByteArrayInputStream bais =
          new ByteArrayInputStream(temp);
        DataInputStream dis = new DataInputStream(bais);
        try {
          String nama = dis.readUTF();
          list.append(nama, null);
        } catch (IOException ioe) {
          ioe.printStackTrace();
        }
      }
      display.setCurrent(list);
    } catch (InvalidRecordIDException invID) {
      invID.printStackTrace();
    } catch (RecordStoreNotOpenException rsnoe) {
      rsnoe.printStackTrace();
    } catch (RecordStoreException rse) {
      rse.printStackTrace();
    }   
     
    display.setCurrent(list);
  }
   
  // inner class untuk mencari data
  class CariNama implements RecordFilter {
       
    private String karakterAwal;
       
    public CariNama(String karakterAwal) {
      this.karakterAwal = karakterAwal.toLowerCase();
    }
       
    public boolean matches(byte[] candidate) {
      String s =
        new String(candidate).toLowerCase().substring(2);           
      return s.startsWith(karakterAwal);
    }
  }
   
}