Java Tutorial/J2ME/RecordStore

Add records to RecordStore

   <source lang="java">

import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.TextBox; import javax.microedition.lcdui.TextField; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordStore; import javax.microedition.rms.RecordStoreNotFoundException; public class addRecordMIDlet extends MIDlet implements CommandListener {

 private Command exitCommand;
 private Display display;
 public addRecordMIDlet() {
   display = Display.getDisplay(this);
   exitCommand = new Command("exit", Command.SCREEN, 1);
 }
 public void startApp() {
   TextBox aTextBox = new TextBox("a text", null, 256, TextField.ANY);
   RecordStore rs = null;
   byte[] nameEmail = null;
   boolean existingOrNot = false;
   boolean OK = true;
   existingOrNot = existing("aRS");
   if (existingOrNot) {
     try {
       rs = RecordStore.openRecordStore("aRS", false);
     } catch (Exception e) {
       OK = false;
     } finally {
       if (OK) {
         aTextBox.setString("aRS Opened");
       } else {
         aTextBox.setString("aRS cannot open");
       }
     }
   } else {
     try {
       rs = RecordStore.openRecordStore("aRS", true);
     } catch (Exception e) {
       OK = false;
     } finally {
       if (OK) {
         aTextBox.setString("Ok");
       } else {
         aTextBox.setString("not ok");
       }
     }
   }
   if (OK)
     try {
       nameEmail = "login@yourname.net".getBytes();
       rs.addRecord(nameEmail, 0, nameEmail.length);
       aTextBox.setString("Added");
     } catch (Exception e) {
       aTextBox.setString("failed");
     }
   if (OK)
     try {
       rs.closeRecordStore();
     } catch (Exception e) {
     }
   String result = new String(nameEmail);
   int position = result.indexOf("=");
   result = "Name:" + result.substring(0, position) + "\n" + "E-mail?"
       + result.substring(position + 1, result.length());
   aTextBox.setString(result);
   aTextBox.addCommand(exitCommand);
   aTextBox.setCommandListener(this);
   display.setCurrent(aTextBox);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public boolean existing(String recordStoreName) {
   boolean existingOrNot = false;
   RecordStore rs = null;
   if (recordStoreName.length() > 32)
     return false;
   try {
     rs = RecordStore.openRecordStore(recordStoreName, false);
   } catch (RecordStoreNotFoundException e) {
     existingOrNot = false;
   } catch (Exception e) {
   } finally {
     try {
       rs.closeRecordStore();
     } catch (Exception e) {
     }
   }
   return existingOrNot;
 }
 public void commandAction(Command c, Displayable s) {
   destroyApp(false);
   notifyDestroyed();
 }

}</source>

delete RecordStore

   <source lang="java">

import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.TextBox; import javax.microedition.lcdui.TextField; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordStore; public class deleteRecordStoreMIDlet extends MIDlet implements CommandListener {

 private Command exitCommand;
 private Command confirmCommand;
 private Display display;
 public deleteRecordStoreMIDlet() {
   display = Display.getDisplay(this);
   exitCommand = new Command("exit", Command.EXIT, 1);
   confirmCommand = new Command("confirm", Command.OK, 1);
 }
 public void startApp() {
   TextBox aTextBox = new TextBox("RecordStore", null, 256, TextField.ANY);
   aTextBox.addCommand(exitCommand);
   aTextBox.addCommand(confirmCommand);
   aTextBox.setCommandListener(this);
   display.setCurrent(aTextBox);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public void commandAction(Command c, Displayable s) {
   if (c.getCommandType() == Command.EXIT) {
     destroyApp(false);
     notifyDestroyed();
   } else {
     try {
       RecordStore.deleteRecordStore("aRS");
     } catch (Exception e) {
     }
   }
 }

}</source>

Filter Fields

   <source lang="java">

import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.DataInputStream; import java.io.DataOutputStream; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.TextBox; import javax.microedition.lcdui.TextField; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordEnumeration; import javax.microedition.rms.RecordFilter; import javax.microedition.rms.RecordStore; import javax.microedition.rms.RecordStoreNotFoundException; public class FilterFieldsMIDlet extends MIDlet implements CommandListener {

 private Command exitCommand;
 private Display display;
 private String[] names = { "A", "B", "C", "D" };
 private int[] chineseScore = { 74, 98, 89, 76 };
 private int[] englishScore = { 67, 89, 89, 78 };
 private int[] mathScore = { 80, 76, 80, 78 };
 public FilterFieldsMIDlet() {
   display = Display.getDisplay(this);
   exitCommand = new Command("Exit", Command.EXIT, 1);
 }
 public void startApp() {
   TextBox aTextBox = new TextBox("Main", null, 256, TextField.ANY);
   RecordStore rs = null;
   byte[] nameEmail = null;
   boolean existingOrNot = false;
   boolean OK = true;
   existingOrNot = existing("aRS3");
   if (existingOrNot) {
     try {
       rs = RecordStore.openRecordStore("aRS3", false);
     } catch (Exception e) {
       OK = false;
     } finally {
       if (OK) {
         aTextBox.setString("Ok");
       } else {
         aTextBox.setString("not tOk");
       }
     }
   } else {
     try {
       rs = RecordStore.openRecordStore("aRS3", true);
     } catch (Exception e) {
       OK = false;
     } finally {
       if (OK) {
         aTextBox.setString("Ok");
       } else {
         aTextBox.setString("Not Ok");
       }
     }
   }
   Student aStudent = null;
   if (OK)
     try {
       for (int i = 0; i < names.length; i++) {
         aStudent = new Student();
         aStudent.write(names[i], chineseScore[i], englishScore[i], mathScore[i]);
         byte[] data = aStudent.changeToByteArray();
         int recordID = aStudent.getRecordID();
         if (recordID != -1) {
           rs.setRecord(recordID, data, 0, data.length);
         } else {
           recordID = rs.addRecord(data, 0, data.length);
           aStudent.setRecordID(recordID);
         }
         aStudent = null;
       }
       aTextBox.setString("Added");
     } catch (Exception e) {
       aTextBox.setString("Failed");
     }
   String result = "";
   aStudent = new Student();
   if (OK)
     try {
       byte[] data;
       int number = 0;
       RecordFilter rf = new averageFilter();
       RecordEnumeration re = rs.enumerateRecords(rf, null, false);
       while (re.hasNextElement()) {
         int recordID = re.nextRecordId();
         data = rs.getRecord(recordID);
         aStudent.changeFromByteArray(data);
         result += recordID + "\n" + "Name:" + aStudent.getName() + "\n"
             + aStudent.getChineseScore() + "\n" + aStudent.getEnglishScore() + "\n"
             + aStudent.getMathScore() + "\n";
         number++;
       }
       result += number;
       aTextBox.setString(result);
     } catch (Exception e) {
       aTextBox.setString("Failed");
       try {
         rs.closeRecordStore();
         System.out.println("1.Closed.");
         RecordStore.deleteRecordStore("aRS3");
         System.out.println("delete OK");
       } catch (Exception x) {
       }
     } finally {
       try {
         if (rs != null)
           rs.closeRecordStore();
         rs.deleteRecordStore("aRS3");
       } catch (Exception e) {
       }
     }
   aTextBox.setString(result);
   aTextBox.addCommand(exitCommand);
   aTextBox.setCommandListener(this);
   display.setCurrent(aTextBox);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public boolean existing(String recordStoreName) {
   boolean existingOrNot = false;
   RecordStore rs = null;
   if (recordStoreName.length() > 32)
     return false;
   try {
     rs = RecordStore.openRecordStore(recordStoreName, false);
   } catch (RecordStoreNotFoundException e) {
     existingOrNot = false;
   } catch (Exception e) {
   } finally {
     try {
       rs.closeRecordStore();
     } catch (Exception e) {
     }
   }
   return existingOrNot;
 }
 public void commandAction(Command c, Displayable s) {
   destroyApp(false);
   notifyDestroyed();
 }

} class averageFilter implements RecordFilter {

 public boolean matches(byte[] candidate) {
   DataInputStream student = new DataInputStream(new ByteArrayInputStream(candidate));
   int average = 0;
   try {
     String dummy = student.readUTF();
     average = (student.readInt() + student.readInt() + student.readInt()) / 3;
   } catch (Exception e) {
   }
   if (average >= 80)
     return true;
   else
     return false;
 }

} class Student {

 private int ID = -1;
 private String name;
 private int chineseScore;
 private int englishScore;
 private int mathScore;
 public void write(String name, int chineseScore, int englishScore, int mathScore) {
   this.name = name;
   this.chineseScore = chineseScore;
   this.englishScore = englishScore;
   this.mathScore = mathScore;
 }
 public void setRecordID(int ID) {
   this.ID = ID;
 }
 public int getRecordID() {
   return ID;
 }
 public byte[] changeToByteArray() {
   byte[] data = null;
   try {
     ByteArrayOutputStream baos = new ByteArrayOutputStream();
     DataOutputStream dos = new DataOutputStream(baos);
     dos.writeUTF(name);
     dos.writeInt(chineseScore);
     dos.writeInt(englishScore);
     dos.writeInt(mathScore);
     data = baos.toByteArray();
     baos.close();
     dos.close();
   } catch (Exception e) {
   }
   return data;
 }
 public void changeFromByteArray(byte[] data) {
   try {
     ByteArrayInputStream bais = new ByteArrayInputStream(data);
     DataInputStream dis = new DataInputStream(bais);
     name = dis.readUTF();
     chineseScore = dis.readInt();
     englishScore = dis.readInt();
     mathScore = dis.readInt();
     bais.close();
     dis.close();
   } catch (Exception e) {
   }
 }
 public String getName() {
   return name;
 }
 public int getChineseScore() {
   return chineseScore;
 }
 public int getEnglishScore() {
   return englishScore;
 }
 public int getMathScore() {
   return mathScore;
 }

}</source>

Get record from RecordStore

   <source lang="java">

import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.TextBox; import javax.microedition.lcdui.TextField; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordStore; import javax.microedition.rms.RecordStoreNotFoundException; public class getRecordMIDlet extends MIDlet implements CommandListener {

 private Command exitCommand = new Command("exit", Command.STOP, 1);
 private Display display;
 public getRecordMIDlet() {
   display = Display.getDisplay(this);
 }
 public void startApp() {
   TextBox aTextBox = new TextBox("Main", null, 256, TextField.ANY);
   RecordStore rs = null;
   boolean existingOrNot = false;
   existingOrNot = existing("aRS");
   if (existingOrNot) {
     try {
       rs = RecordStore.openRecordStore("aRS", false);
     } catch (Exception e) {
     }
   } else {
     try {
       rs = RecordStore.openRecordStore("aRS", true);
     } catch (Exception e) {
     } finally {
     }
   }
   try {
     String record = "";
     for (int i = 1; i < rs.getNextRecordID(); i++) {
       record = new String(rs.getRecord(i));
     }
     aTextBox.setString(record);
   } catch (Exception e) {
     aTextBox.setString("Failed");
     try {
       rs.closeRecordStore();
       RecordStore.deleteRecordStore("aRS");
     } catch (Exception x) {
     }
   }
   try {
     rs.closeRecordStore();
   } catch (Exception e) {
   }
   aTextBox.addCommand(exitCommand);
   aTextBox.setCommandListener(this);
   display.setCurrent(aTextBox);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public boolean existing(String recordStoreName) {
   boolean existingOrNot = false;
   RecordStore rs = null;
   if (recordStoreName.length() > 32)
     return false;
   try {
     rs = RecordStore.openRecordStore(recordStoreName, false);
   } catch (RecordStoreNotFoundException e) {
     existingOrNot = false;
   } catch (Exception e) {
   } finally {
     try {
       rs.closeRecordStore();
     } catch (Exception e) {
     }
   }
   return existingOrNot;
 }
 public void commandAction(Command c, Displayable s) {
   destroyApp(false);
   notifyDestroyed();
 }

}</source>

Load yahoo stock quote

   <source lang="java">

/* License

* 
* Copyright 1994-2004 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. 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 MICROSYSTEMS, 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. 
*/

import java.io.ByteArrayOutputStream; import java.io.DataOutputStream; import java.io.IOException; import java.io.InputStream; import javax.microedition.io.Connector; import javax.microedition.io.StreamConnection; import javax.microedition.lcdui.Choice; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.List; import javax.microedition.lcdui.TextBox; import javax.microedition.lcdui.TextField; import javax.microedition.lcdui.Ticker; import javax.microedition.midlet.MIDlet; import javax.microedition.midlet.MIDletStateChangeException; import javax.microedition.rms.RecordEnumeration; import javax.microedition.rms.RecordStore; import javax.microedition.rms.RecordStoreException; import javax.microedition.rms.RecordStoreNotOpenException; public class QuotesMIDlet extends MIDlet implements CommandListener {

 Display display = null;
 List menu = null; // main menu
 List choose = null;
 TextBox input = null;
 Ticker ticker = new Ticker("Database Application");
 String quoteServer = "http://quote.yahoo.ru/d/quotes.csv?s=";
 String quoteFormat = "&f=slc1wop";
 static final Command backCommand = new Command("Back", Command.BACK, 0);
 static final Command mainMenuCommand = new Command("Main", Command.SCREEN, 1);
 static final Command saveCommand = new Command("Save", Command.OK, 2);
 static final Command exitCommand = new Command("Exit", Command.STOP, 3);
 String currentMenu = null;
 // Stock data
 String name, date, price;
 StockDB db = null;
 public QuotesMIDlet() {
 }
 public void startApp() throws MIDletStateChangeException {
   display = Display.getDisplay(this);
   // open a db stock file
   try {
     db = new StockDB("stocks");
   } catch (Exception e) {
   }
   menu = new List("Stocks Database", Choice.IMPLICIT);
   menu.append("List Stocks", null);
   menu.append("Add A New Stock", null);
   menu.addCommand(exitCommand);
   menu.setCommandListener(this);
   menu.setTicker(ticker);
   mainMenu();
 }
 public void pauseApp() {
   display = null;
   choose = null;
   menu = null;
   ticker = null;
   try {
     db.close();
     db = null;
   } catch (Exception e) {
   }
 }
 public void destroyApp(boolean unconditional) {
   try {
     db.close();
   } catch (Exception e) {
   }
   notifyDestroyed();
 }
 void mainMenu() {
   display.setCurrent(menu);
   currentMenu = "Main";
 }
 public String tickerString() {
   StringBuffer ticks = null;
   try {
     RecordEnumeration enum = db.enumerate();
     ticks = new StringBuffer();
     while (enum.hasNextElement()) {
       String stock1 = new String(enum.nextRecord());
       ticks.append(Stock.getName(stock1));
       ticks.append(" @ ");
       ticks.append(Stock.getPrice(stock1));
       ticks.append("    ");
     }
   } catch (Exception ex) {
   }
   return (ticks.toString());
 }
 public void addStock() {
   input = new TextBox("Enter a Stock Name:", "", 5, TextField.ANY);
   input.setTicker(ticker);
   input.addCommand(saveCommand);
   input.addCommand(backCommand);
   input.setCommandListener(this);
   input.setString("");
   display.setCurrent(input);
   currentMenu = "Add";
 }
 public String getQuote(String input) throws IOException,
     NumberFormatException {
   String url = quoteServer + input + quoteFormat;
   StreamConnection c = (StreamConnection) Connector.open(url,
       Connector.READ_WRITE);
   InputStream is = c.openInputStream();
   StringBuffer sb = new StringBuffer();
   int ch;
   while ((ch = is.read()) != -1) {
     sb.append((char) ch);
   }
   return (sb.toString());
 }
 public void listStocks() {
   choose = new List("Choose Stocks", Choice.MULTIPLE);
   choose.setTicker(new Ticker(tickerString()));
   choose.addCommand(backCommand);
   choose.setCommandListener(this);
   try {
     RecordEnumeration re = db.enumerate();
     while (re.hasNextElement()) {
       String theStock = new String(re.nextRecord());
       choose.append(Stock.getName(theStock) + " @ "
           + Stock.getPrice(theStock), null);
     }
   } catch (Exception ex) {
   }
   display.setCurrent(choose);
   currentMenu = "List";
 }
 public void commandAction(Command c, Displayable d) {
   String label = c.getLabel();
   if (label.equals("Exit")) {
     destroyApp(true);
   } else if (label.equals("Save")) {
     if (currentMenu.equals("Add")) {
       // add it to database
       try {
         String userInput = input.getString();
         String pr = getQuote(userInput);
         db.addNewStock(pr);
         ticker.setString(tickerString());
       } catch (IOException e) {
       } catch (NumberFormatException se) {
       }
       mainMenu();
     }
   } else if (label.equals("Back")) {
     if (currentMenu.equals("List")) {
       // go back to menu
       mainMenu();
     } else if (currentMenu.equals("Add")) {
       // go back to menu
       mainMenu();
     }
   } else {
     List down = (List) display.getCurrent();
     switch (down.getSelectedIndex()) {
     case 0:
       listStocks();
       break;
     case 1:
       addStock();
       break;
     }
   }
 }

} class StockDB {

 RecordStore recordStore = null;
 public StockDB() {
 }
 public StockDB(String fileName) {
   try {
     recordStore = RecordStore.openRecordStore(fileName, true);
   } catch (RecordStoreException rse) {
     rse.printStackTrace();
   }
 }
 public void close() throws RecordStoreNotOpenException, RecordStoreException {
   if (recordStore.getNumRecords() == 0) {
     String fileName = recordStore.getName();
     recordStore.closeRecordStore();
     recordStore.deleteRecordStore(fileName);
   } else {
     recordStore.closeRecordStore();
   }
 }
 public synchronized void addNewStock(String record) {
   ByteArrayOutputStream baos = new ByteArrayOutputStream();
   DataOutputStream outputStream = new DataOutputStream(baos);
   try {
     outputStream.writeUTF(record);
   } catch (IOException ioe) {
     System.out.println(ioe);
     ioe.printStackTrace();
   }
   byte[] b = baos.toByteArray();
   try {
     recordStore.addRecord(b, 0, b.length);
   } catch (RecordStoreException rse) {
     System.out.println(rse);
     rse.printStackTrace();
   }
 }
 public synchronized RecordEnumeration enumerate()
     throws RecordStoreNotOpenException {
   return recordStore.enumerateRecords(null, null, false);
 }

} /*

* License
* 
* Copyright 1994-2004 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. 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 MICROSYSTEMS, 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.
*/

class Stock {

 private static String name, time, price;
 public static void parse(String data) {
   int index = data.indexOf(""");
   name = data.substring(++index, (index = data.indexOf(""", index)));
   index += 3;
   time = data.substring(index, (index = data.indexOf("-", index)) - 1);
   index += 5;
   price = data.substring(index, (index = data.indexOf("<", index)));
 }
 public static String getName(String record) {
   parse(record);
   return (name);
 }
 public static String getPrice(String record) {
   parse(record);
   return (price);
 }

}</source>

Mixed Record Enumeration

   <source lang="java">

import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.DataInputStream; import java.io.DataOutputStream; import javax.microedition.lcdui.Alert; import javax.microedition.lcdui.AlertType; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Form; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordEnumeration; import javax.microedition.rms.RecordStore; public class J2MEMixedRecordEnumerationExample extends MIDlet implements CommandListener {

 private Display display;
 private Alert alert;
 private Form form = new Form("Mixed RecordEnumeration");
 private Command exit = new Command("Exit", Command.SCREEN, 1);
 private Command start = new Command("Start", Command.SCREEN, 1);
 private RecordStore recordstore = null;
 private RecordEnumeration recordEnumeration = null;
 public J2MEMixedRecordEnumerationExample() {
   display = Display.getDisplay(this);
   form.addCommand(exit);
   form.addCommand(start);
   form.setCommandListener(this);
 }
 public void startApp() {
   display.setCurrent(form);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public void commandAction(Command command, Displayable displayable) {
   if (command == exit) {
     destroyApp(true);
     notifyDestroyed();
   } else if (command == start) {
     try {
       recordstore = RecordStore.openRecordStore("myRecordStore", true);
       byte[] outputRecord;
       String outputString[] = { "First Record", "Second Record", "Third Record" };
       int outputInteger[] = { 15, 10, 5 };
       boolean outputBoolean[] = { true, false, true };
       ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
       DataOutputStream outputDataStream = new DataOutputStream(outputStream);
       for (int x = 0; x < 3; x++) {
         outputDataStream.writeUTF(outputString[x]);
         outputDataStream.writeBoolean(outputBoolean[x]);
         outputDataStream.writeInt(outputInteger[x]);
         outputDataStream.flush();
         outputRecord = outputStream.toByteArray();
         recordstore.addRecord(outputRecord, 0, outputRecord.length);
       }
       outputStream.reset();
       outputStream.close();
       outputDataStream.close();
       StringBuffer buffer = new StringBuffer();
       byte[] byteInputData = new byte[300];
       ByteArrayInputStream inputStream = new ByteArrayInputStream(byteInputData);
       DataInputStream inputDataStream = new DataInputStream(inputStream);
       recordEnumeration = recordstore.enumerateRecords(null, null, false);
       while (recordEnumeration.hasNextElement()) {
         recordstore.getRecord(recordEnumeration.nextRecordId(), byteInputData, 0);
         buffer.append(inputDataStream.readUTF());
         buffer.append("\n");
         buffer.append(inputDataStream.readBoolean());
         buffer.append("\n");
         buffer.append(inputDataStream.readInt());
         buffer.append("\n");
         alert = new Alert("Reading", buffer.toString(), null, AlertType.WARNING);
         alert.setTimeout(Alert.FOREVER);
         display.setCurrent(alert);
       }
       inputStream.close();
       recordstore.closeRecordStore();
       if (RecordStore.listRecordStores() != null) {
         RecordStore.deleteRecordStore("myRecordStore");
         recordEnumeration.destroy();
       }
     } catch (Exception error) {
       alert = new Alert("Error Removing", error.toString(), null, AlertType.WARNING);
       alert.setTimeout(Alert.FOREVER);
       display.setCurrent(alert);
     }
   }
 }

}</source>

Read and write mixed data types with RecordStore

   <source lang="java">

import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.DataInputStream; import java.io.DataOutputStream; import javax.microedition.lcdui.Alert; import javax.microedition.lcdui.AlertType; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Form; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordStore; public class J2MEWriteReadMixedDataTypesExample extends MIDlet implements CommandListener {

 private Display display;
 private Alert alert;
 private Form form = new Form("Mixed Record");
 private Command exit = new Command("Exit", Command.SCREEN, 1);
 private Command start = new Command("Start", Command.SCREEN, 1);
 private RecordStore recordstore = null;
 public J2MEWriteReadMixedDataTypesExample() {
   display = Display.getDisplay(this);
   form.addCommand(exit);
   form.addCommand(start);
   form.setCommandListener(this);
 }
 public void startApp() {
   display.setCurrent(form);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public void commandAction(Command command, Displayable displayable) {
   if (command == exit) {
     destroyApp(true);
     notifyDestroyed();
   } else if (command == start) {
     try {
       recordstore = RecordStore.openRecordStore("myRecordStore", true);
       byte[] outputRecord;
       String outputString = "First Record";
       int outputInteger = 15;
       boolean outputBoolean = true;
       ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
       DataOutputStream outputDataStream = new DataOutputStream(outputStream);
       outputDataStream.writeUTF(outputString);
       outputDataStream.writeBoolean(outputBoolean);
       outputDataStream.writeInt(outputInteger);
       outputDataStream.flush();
       outputRecord = outputStream.toByteArray();
       recordstore.addRecord(outputRecord, 0, outputRecord.length);
       outputStream.reset();
       outputStream.close();
       outputDataStream.close();
       String inputString = null;
       int inputInteger = 0;
       boolean inputBoolean = false;
       byte[] byteInputData = new byte[100];
       ByteArrayInputStream inputStream = new ByteArrayInputStream(byteInputData);
       DataInputStream inputDataStream = new DataInputStream(inputStream);
       for (int x = 1; x <= recordstore.getNumRecords(); x++) {
         recordstore.getRecord(x, byteInputData, 0);
         inputString = inputDataStream.readUTF();
         inputBoolean = inputDataStream.readBoolean();
         inputInteger = inputDataStream.readInt();
         inputStream.reset();
       }
       inputStream.close();
       inputDataStream.close();
       alert = new Alert("Reading", inputString + " " + inputInteger + " " + inputBoolean, null,
           AlertType.WARNING);
       alert.setTimeout(Alert.FOREVER);
       display.setCurrent(alert);
       recordstore.closeRecordStore();
       if (RecordStore.listRecordStores() != null) {
         RecordStore.deleteRecordStore("myRecordStore");
       }
     } catch (Exception error) {
       alert = new Alert("Error Removing", error.toString(), null, AlertType.WARNING);
       alert.setTimeout(Alert.FOREVER);
       display.setCurrent(alert);
     }
   }
 }

}</source>

Record Enumeration

   <source lang="java">

import javax.microedition.lcdui.Alert; import javax.microedition.lcdui.AlertType; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Form; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordEnumeration; import javax.microedition.rms.RecordStore; public class J2MERecordStoreExample extends MIDlet implements CommandListener {

 private Display display;
 private Alert alert;
 private Form form = new Form("Record Store");
 private Command exit = new Command("Exit", Command.SCREEN, 1);
 private Command start = new Command("Start", Command.SCREEN, 1);
 private RecordStore recordstore = null;
 private RecordEnumeration recordenumeration = null;
 public J2MERecordStoreExample() {
   display = Display.getDisplay(this);
   form.addCommand(exit);
   form.addCommand(start);
   form.setCommandListener(this);
 }
 public void startApp() {
   display.setCurrent(form);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public void commandAction(Command command, Displayable displayable) {
   if (command == exit) {
     destroyApp(true);
     notifyDestroyed();
   } else if (command == start) {
     try {
       recordstore = RecordStore.openRecordStore("myRecordStore", true);
     } catch (Exception error) {
       alert = new Alert("Error Creating", error.toString(), null, AlertType.WARNING);
       alert.setTimeout(Alert.FOREVER);
       display.setCurrent(alert);
     }
     try {
       recordstore.closeRecordStore();
     } catch (Exception error) {
       alert = new Alert("Error Closing", error.toString(), null, AlertType.WARNING);
       alert.setTimeout(Alert.FOREVER);
       display.setCurrent(alert);
     }
     if (RecordStore.listRecordStores() != null) {
       try {
         RecordStore.deleteRecordStore("myRecordStore");
       } catch (Exception error) {
         alert = new Alert("Error Removing", error.toString(), null, AlertType.WARNING);
         alert.setTimeout(Alert.FOREVER);
         display.setCurrent(alert);
       }
     }
   }
 }

}</source>

Record Monitor

   <source lang="java">

import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.TextBox; import javax.microedition.lcdui.TextField; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordListener; import javax.microedition.rms.RecordStore; import javax.microedition.rms.RecordStoreNotFoundException; public class RecordMonitorMIDlet extends MIDlet implements CommandListener, RecordListener {

 private Command exitCommand = new Command("Exit", Command.EXIT, 1);
 private Command deleteCommand= new Command("Delete", Command.SCREEN, 1);
 private Command changeCommand = new Command("Edit", Command.SCREEN, 1);
 private Display display;
 RecordStore mainRS = null;
 RecordStore backupRS = null;
 public RecordMonitorMIDlet() {
   display = Display.getDisplay(this);
 }
 public void startApp() {
   TextBox aTextBox = new TextBox("Main", null, 256, TextField.ANY);
   byte[] nameEmail = null;
   boolean existingOrNot = false;
   boolean OK = true;
   existingOrNot = existing("aRS1");
   if (existingOrNot) {
     try {
       mainRS = RecordStore.openRecordStore("aRS1", false);
       mainRS.addRecordListener(this);
     } catch (Exception e) {
       OK = false;
     } finally {
       if (OK) {
         aTextBox.setString("Ok");
       } else {
         aTextBox.setString("Failed");
       }
     }
   } else {
     try {
       mainRS = RecordStore.openRecordStore("aRS1", true);
       mainRS.addRecordListener(this);
     } catch (Exception e) {
       OK = false;
     } finally {
       if (OK) {
         aTextBox.setString("Ok");
       } else {
         aTextBox.setString("Falied");
       }
     }
   }
   if (OK)
     try {
       backupRS = RecordStore.openRecordStore("aRS2", true);
     } catch (Exception e) {
     }
   if (OK)
     try {
       nameEmail = "JIDCA=login@yourname.net".getBytes();
       mainRS.addRecord(nameEmail, 0, nameEmail.length);
       aTextBox.setString("Added");
     } catch (Exception e) {
       aTextBox.setString("Add Falied");
     }
   String result = new String(nameEmail);
   int position = result.indexOf("=");
   result = "Name:" + result.substring(0, position) + "\n" + "E-mail?"
       + result.substring(position + 1, result.length());
   aTextBox.setString(result);
   try {
     int recordID = mainRS.getNextRecordID() - 1;
     byte[] newNameEmail = "Logis=login@yourname.net".getBytes();
     mainRS.setRecord(recordID, newNameEmail, 0, newNameEmail.length);
     recordID = mainRS.getNextRecordID() - 1;
     mainRS.deleteRecord(recordID);
   } catch (Exception e) {
   }
   aTextBox.addCommand(exitCommand);
   aTextBox.addCommand(deleteCommand);
   aTextBox.addCommand(changeCommand);
   aTextBox.setCommandListener(this);
   display.setCurrent(aTextBox);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
   try {
     if (mainRS != null) {
       mainRS.closeRecordStore();
     }
   } catch (Exception e) {
   }
   try {
     if (backupRS != null) {
       backupRS.closeRecordStore();
     }
   } catch (Exception e) {
   }
 }
 public boolean existing(String recordStoreName) {
   boolean existingOrNot = false;
   RecordStore mainRS = null;
   if (recordStoreName.length() > 32)
     return false;
   try {
     mainRS = RecordStore.openRecordStore(recordStoreName, false);
   } catch (RecordStoreNotFoundException e) {
     existingOrNot = false;
   } catch (Exception e) {
   } finally {
     try {
       mainRS.closeRecordStore();
     } catch (Exception e) {
     }
   }
   return existingOrNot;
 }
 public void commandAction(Command c, Displayable s) {
   if (c == deleteCommand) {
     try {
       int recordID = mainRS.getNextRecordID() - 1;
       mainRS.deleteRecord(recordID);
     } catch (Exception e) {
     }
   } else if (c == changeCommand) {
     try {
       int recordID = mainRS.getNextRecordID() - 1;
       byte[] newNameEmail = "Logis=login@yourname.net".getBytes();
       mainRS.setRecord(recordID, newNameEmail, 0, newNameEmail.length);
     } catch (Exception e) {
     }
   } else {
     destroyApp(false);
     notifyDestroyed();
   }
 }
 public void recordAdded(RecordStore recordStore, int recordID) {
   if (recordStore == mainRS) {
     try {
       byte[] data = recordStore.getRecord(recordID);
       int recID = backupRS.addRecord(data, 0, data.length);
     } catch (Exception e) {
     }
   }
 }
 public void recordChanged(RecordStore recordStore, int recordID) {
   if (recordStore == mainRS) {
     try {
       byte[] data = recordStore.getRecord(recordID);
       backupRS.setRecord(recordID, data, 0, data.length);
     } catch (Exception e) {
     }
   }
 }
 public void recordDeleted(RecordStore recordStore, int recordID) {
   if (recordStore == mainRS) {
     try {
       backupRS.deleteRecord(recordID);
     } catch (Exception e) {
     }
   }
 }

}</source>

RecordStore read and write

   <source lang="java">

import javax.microedition.lcdui.Alert; import javax.microedition.lcdui.AlertType; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Form; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordStore; public class J2MEWriteReadExample extends MIDlet implements CommandListener {

 private Display display;
 private Alert alert;
 private Form form = new Form("Record");
 private Command exit = new Command("Exit", Command.SCREEN, 1);
 private Command start = new Command("Start", Command.SCREEN, 1);
 private RecordStore recordstore = null;
 public J2MEWriteReadExample() {
   display = Display.getDisplay(this);
   form.addCommand(exit);
   form.addCommand(start);
   form.setCommandListener(this);
 }
 public void startApp() {
   display.setCurrent(form);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public void commandAction(Command command, Displayable displayable) {
   if (command == exit) {
     destroyApp(true);
     notifyDestroyed();
   } else if (command == start) {
     try {
       recordstore = RecordStore.openRecordStore("myRecordStore", true);
       String outputData = "First Record";
       byte[] byteOutputData = outputData.getBytes();
       recordstore.addRecord(byteOutputData, 0, byteOutputData.length);
       byte[] byteInputData = new byte[1];
       int length = 0;
       for (int x = 1; x <= recordstore.getNumRecords(); x++) {
         if (recordstore.getRecordSize(x) > byteInputData.length) {
           byteInputData = new byte[recordstore.getRecordSize(x)];
         }
         length = recordstore.getRecord(x, byteInputData, 0);
       }
       alert = new Alert("Reading", new String(byteInputData, 0, length), null, AlertType.WARNING);
       alert.setTimeout(Alert.FOREVER);
       display.setCurrent(alert);
       recordstore.closeRecordStore();
       if (RecordStore.listRecordStores() != null) {
         RecordStore.deleteRecordStore("myRecordStore");
       }
     } catch (Exception error) {
       alert = new Alert("Error Removing", error.toString(), null, AlertType.WARNING);
       alert.setTimeout(Alert.FOREVER);
       display.setCurrent(alert);
     }
   }
 }

}</source>

Retrieve All

   <source lang="java">

import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.DataInputStream; import java.io.DataOutputStream; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.TextBox; import javax.microedition.lcdui.TextField; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordEnumeration; import javax.microedition.rms.RecordFilter; import javax.microedition.rms.RecordStore; import javax.microedition.rms.RecordStoreNotFoundException; public class RetrieveAllMIDlet extends MIDlet implements CommandListener {

 private Command exitCommand = new Command("Exit", Command.EXIT, 1);
 private Display display;
 private String[] names = { "A", "B", "C", "D" };
 private int[] chineseScore = { 74, 98, 89, 76 };
 private int[] englishScore = { 67, 89, 89, 78 };
 private int[] mathScore = { 80, 76, 80, 78 };
 public RetrieveAllMIDlet() {
   display = Display.getDisplay(this);
 }
 public void startApp() {
   TextBox aTextBox = new TextBox("Main", null, 256, TextField.ANY);
   RecordStore rs = null;
   boolean existingOrNot = false;
   existingOrNot = existing("aRS3");
   if (existingOrNot) {
     try {
       rs = RecordStore.openRecordStore("aRS3", false);
     } catch (Exception e) {
     }
   } else {
     try {
       rs = RecordStore.openRecordStore("aRS3", true);
     } catch (Exception e) {
     }
   }
   Student aStudent = null;
   try {
     for (int i = 0; i < names.length; i++) {
       aStudent = new Student();
       aStudent.write(names[i], chineseScore[i], englishScore[i], mathScore[i]);
       byte[] data = aStudent.changeToByteArray();
       int recordID = aStudent.getRecordID();
       if (recordID != -1) {
         rs.setRecord(recordID, data, 0, data.length);
       } else {
         recordID = rs.addRecord(data, 0, data.length);
         aStudent.setRecordID(recordID);
       }
       aStudent = null;
     }
     aTextBox.setString("Adding done");
   } catch (Exception e) {
     aTextBox.setString("Add Falied");
   }
   String result = "";
   aStudent = new Student();
   try {
     byte[] data;
     int number = 0;
     RecordFilter rf = new averageFilter();
     RecordEnumeration re = rs.enumerateRecords(rf, null, false);
     while (re.hasNextElement()) {
       int recordID = re.nextRecordId();
       data = rs.getRecord(recordID);
       aStudent.changeFromByteArray(data);
       result += recordID + "\n" + "Name:" + aStudent.getName() + "\n" + ":"
           + aStudent.getChineseScore() + "\n" + ":" + aStudent.getEnglishScore() + "\n" + ":"
           + aStudent.getMathScore() + "\n";
       number++;
     }
     result += number + "\n";
     aTextBox.setString(result);
   } catch (Exception e) {
     aTextBox.setString("Failed!");
     try {
       rs.closeRecordStore();
       RecordStore.deleteRecordStore("aRS3");
     } catch (Exception x) {
     }
   } finally {
     try {
       if (rs != null)
         rs.closeRecordStore();
       rs.deleteRecordStore("aRS3");
     } catch (Exception e) {
     }
   }
   aTextBox.setString(result);
   aTextBox.addCommand(exitCommand);
   aTextBox.setCommandListener(this);
   display.setCurrent(aTextBox);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public boolean existing(String recordStoreName) {
   boolean existingOrNot = false;
   RecordStore rs = null;
   if (recordStoreName.length() > 32)
     return false;
   try {
     rs = RecordStore.openRecordStore(recordStoreName, false);
   } catch (RecordStoreNotFoundException e) {
     existingOrNot = false;
   } catch (Exception e) {
   } finally {
     try {
       rs.closeRecordStore();
     } catch (Exception e) {
     }
   }
   return existingOrNot;
 }
 public void commandAction(Command c, Displayable s) {
   destroyApp(false);
   notifyDestroyed();
 }

} class Student {

 private int ID = -1;
 private String name;
 private int chineseScore;
 private int englishScore;
 private int mathScore;
 public void write(String name, int chineseScore, int englishScore, int mathScore) {
   this.name = name;
   this.chineseScore = chineseScore;
   this.englishScore = englishScore;
   this.mathScore = mathScore;
 }
 public void setRecordID(int ID) {
   this.ID = ID;
 }
 public int getRecordID() {
   return ID;
 }
 public byte[] changeToByteArray() {
   byte[] data = null;
   try {
     ByteArrayOutputStream baos = new ByteArrayOutputStream();
     DataOutputStream dos = new DataOutputStream(baos);
     dos.writeUTF(name);
     dos.writeInt(chineseScore);
     dos.writeInt(englishScore);
     dos.writeInt(mathScore);
     data = baos.toByteArray();
     baos.close();
     dos.close();
   } catch (Exception e) {
   }
   return data;
 }
 public void changeFromByteArray(byte[] data) {
   try {
     ByteArrayInputStream bais = new ByteArrayInputStream(data);
     DataInputStream dis = new DataInputStream(bais);
     name = dis.readUTF();
     chineseScore = dis.readInt();
     englishScore = dis.readInt();
     mathScore = dis.readInt();
     bais.close();
     dis.close();
   } catch (Exception e) {
   }
 }
 public String getName() {
   return name;
 }
 public int getChineseScore() {
   return chineseScore;
 }
 public int getEnglishScore() {
   return englishScore;
 }
 public int getMathScore() {
   return mathScore;
 }

} class averageFilter implements RecordFilter {

 public boolean matches(byte[] candidate) {
   DataInputStream student = new DataInputStream(new ByteArrayInputStream(candidate));
   int average = 0;
   try {
     average = (student.readInt() + student.readInt() + student.readInt()) / 3;
   } catch (Exception e) {
   }
   if (average >= 80)
     return true;
   else
     return false;
 }

}</source>

Save data to RecordStore

   <source lang="java">

import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.TextBox; import javax.microedition.lcdui.TextField; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.InvalidRecordIDException; import javax.microedition.rms.RecordStore; import javax.microedition.rms.RecordStoreException; import javax.microedition.rms.RecordStoreNotFoundException; import javax.microedition.rms.RecordStoreNotOpenException; public class RecordIDMIDlet extends MIDlet implements CommandListener {

 private Command exitCommand= new Command("Exit", Command.EXIT, 1);
 private Display display;
 public RecordIDMIDlet() {
   display = Display.getDisplay(this);
 }
 public void startApp() {
   TextBox aTextBox = new TextBox("Main", null, 256, TextField.ANY);
   RecordStore rs = null;
   byte[] name = null;
   boolean existingOrNot = false;
   boolean OK = true;
   existingOrNot = existing("aRS");
   if (existingOrNot) {
     try {
       rs = RecordStore.openRecordStore("aRS", false);
     } catch (Exception e) {
       OK = false;
     } finally {
       if (OK) {
         aTextBox.setString("Ok");
       } else {
         aTextBox.setString("Failed");
       }
     }
   } else {
     try {
       rs = RecordStore.openRecordStore("aRS", true);
     } catch (Exception e) {
       OK = false;
     } finally {
       if (OK) {
         aTextBox.setString("Ok");
       } else {
         aTextBox.setString("Failed");
       }
     }
   }
   if (OK) {
     try {
       for (int i = 1; i <= 3; i++) {
         name = ("Name " + i).getBytes();
         rs.addRecord(name, 0, name.length);
       }
     } catch (Exception e) {
       aTextBox.setString("Add Falied");
     }
     try {
       rs.deleteRecord(1);
       aTextBox.setString("recordID Delete");
     } catch (InvalidRecordIDException e) {
       try {
         aTextBox.setString(rs.getNumRecords() + "recordID");
       } catch (RecordStoreNotOpenException rse) {
       }
     } catch (RecordStoreException e) {
     } finally {
       try {
         rs.closeRecordStore();
       } catch (Exception e) {
       }
     }
   }
   aTextBox.addCommand(exitCommand);
   aTextBox.setCommandListener(this);
   display.setCurrent(aTextBox);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public boolean existing(String recordStoreName) {
   boolean existingOrNot = false;
   RecordStore rs = null;
   if (recordStoreName.length() > 32)
     return false;
   try {
     rs = RecordStore.openRecordStore(recordStoreName, false);
   } catch (RecordStoreNotFoundException e) {
     existingOrNot = false;
   } catch (Exception e) {
   } finally {
     try {
       rs.closeRecordStore();
     } catch (Exception e) {
     }
   }
   return existingOrNot;
 }
 public void commandAction(Command c, Displayable s) {
   destroyApp(false);
   notifyDestroyed();
 }

}</source>

Search Mixed Record Data Type

   <source lang="java">

import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.DataInputStream; import java.io.DataOutputStream; import javax.microedition.lcdui.Alert; import javax.microedition.lcdui.AlertType; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Form; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordEnumeration; import javax.microedition.rms.RecordFilter; import javax.microedition.rms.RecordStore; public class J2MESearchMixedRecordDataTypeExample extends MIDlet implements CommandListener {

 private Display display;
 private Alert alert;
 private Form form = new Form("Mixed RecordEnumeration");
 private Command exit = new Command("Exit", Command.SCREEN, 1);
 private Command start = new Command("Start", Command.SCREEN, 1);
 private RecordStore recordstore = null;
 private RecordEnumeration recordEnumeration = null;
 private Filter filter = null;
 public J2MESearchMixedRecordDataTypeExample() {
   display = Display.getDisplay(this);
   form.addCommand(exit);
   form.addCommand(start);
   form.setCommandListener(this);
 }
 public void startApp() {
   display.setCurrent(form);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public void commandAction(Command command, Displayable displayable) {
   if (command == exit) {
     destroyApp(true);
     notifyDestroyed();
   } else if (command == start) {
     try {
       recordstore = RecordStore.openRecordStore("myRecordStore", true);
       byte[] outputRecord;
       String outputString[] = { "A", "B", "M" };
       int outputInteger[] = { 15, 10, 5 };
       ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
       DataOutputStream outputDataStream = new DataOutputStream(outputStream);
       for (int x = 0; x < 3; x++) {
         outputDataStream.writeUTF(outputString[x]);
         outputDataStream.writeInt(outputInteger[x]);
         outputDataStream.flush();
         outputRecord = outputStream.toByteArray();
         recordstore.addRecord(outputRecord, 0, outputRecord.length);
         outputStream.reset();
       }
       outputStream.close();
       outputDataStream.close();
       String inputString;
       byte[] byteInputData = new byte[300];
       ByteArrayInputStream inputStream = new ByteArrayInputStream(byteInputData);
       DataInputStream inputDataStream = new DataInputStream(inputStream);
       if (recordstore.getNumRecords() > 0) {
         filter = new Filter("Mary");
         recordEnumeration = recordstore.enumerateRecords(filter, null, false);
         while (recordEnumeration.hasNextElement()) {
           recordstore.getRecord(recordEnumeration.nextRecordId(), byteInputData, 0);
           inputString = inputDataStream.readUTF() + " " + inputDataStream.readInt();
           alert = new Alert("Reading", inputString, null, AlertType.WARNING);
           alert.setTimeout(Alert.FOREVER);
           display.setCurrent(alert);
         }
       }
       inputStream.close();
       recordstore.closeRecordStore();
       if (RecordStore.listRecordStores() != null) {
         RecordStore.deleteRecordStore("myRecordStore");
         filter.filterClose();
         recordEnumeration.destroy();
       }
     } catch (Exception error) {
       alert = new Alert("Error Removing", error.toString(), null, AlertType.WARNING);
       alert.setTimeout(Alert.FOREVER);
       display.setCurrent(alert);
     }
   }
 }

} class Filter implements RecordFilter {

 private String search = null;
 private ByteArrayInputStream inputstream = null;
 private DataInputStream datainputstream = null;
 public Filter(String searchcriteria) {
   search = searchcriteria;
 }
 public boolean matches(byte[] suspect) {
   String string = null;
   try {
     inputstream = new ByteArrayInputStream(suspect);
     datainputstream = new DataInputStream(inputstream);
     string = datainputstream.readUTF();
   } catch (Exception error) {
     return false;
   }
   if (string != null && string.indexOf(search) != -1)
     return true;
   else
     return false;
 }
 public void filterClose() {
   try {
     if (inputstream != null) {
       inputstream.close();
     }
     if (datainputstream != null) {
       datainputstream.close();
     }
   } catch (Exception error) {
   }
 }

}</source>

Search record in RecordStore

   <source lang="java">

import java.io.ByteArrayInputStream; import java.io.DataInputStream; import javax.microedition.lcdui.Alert; import javax.microedition.lcdui.AlertType; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Form; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordEnumeration; import javax.microedition.rms.RecordFilter; import javax.microedition.rms.RecordStore; public class J2MESearchExample extends MIDlet implements CommandListener {

 private Display display;
 private Alert alert;
 private Form form = new Form("Mixed RecordEnumeration", null);
 private Command exit = new Command("Exit", Command.SCREEN, 1);
 private Command start = new Command("Start", Command.SCREEN, 1);
 private RecordStore recordstore = null;
 private RecordEnumeration recordEnumeration = null;
 private Filter filter = null;
 public J2MESearchExample() {
   display = Display.getDisplay(this);
   form.addCommand(exit);
   form.addCommand(start);
   form.setCommandListener(this);
 }
 public void startApp() {
   display.setCurrent(form);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public void commandAction(Command command, Displayable displayable) {
   if (command == exit) {
     destroyApp(true);
     notifyDestroyed();
   } else if (command == start) {
     try {
       recordstore = RecordStore.openRecordStore("myRecordStore", true);
       String outputData[] = { "M", "B", "A" };
       for (int x = 0; x < 3; x++) {
         byte[] byteOutputData = outputData[x].getBytes();
         recordstore.addRecord(byteOutputData, 0, byteOutputData.length);
       }
       filter = new Filter("Bob");
       recordEnumeration = recordstore.enumerateRecords(filter, null, false);
       if (recordEnumeration.numRecords() > 0) {
         String string = new String(recordEnumeration.nextRecord());
         alert = new Alert("Reading", string, null, AlertType.WARNING);
         alert.setTimeout(Alert.FOREVER);
         display.setCurrent(alert);
       }
       recordstore.closeRecordStore();
       if (RecordStore.listRecordStores() != null) {
         RecordStore.deleteRecordStore("myRecordStore");
         recordEnumeration.destroy();
         filter.filterClose();
       }
     } catch (Exception error) {
       alert = new Alert("Error Removing", error.toString(), null, AlertType.WARNING);
       alert.setTimeout(Alert.FOREVER);
       display.setCurrent(alert);
     }
   }
 }

} class Filter implements RecordFilter {

 private String search = null;
 private ByteArrayInputStream inputstream = null;
 private DataInputStream datainputstream = null;
 public Filter(String search) {
   this.search = search.toLowerCase();
 }
 public boolean matches(byte[] suspect) {
   String string = new String(suspect).toLowerCase();
   if (string != null && string.indexOf(search) != -1)
     return true;
   else
     return false;
 }
 public void filterClose() {
   try {
     if (inputstream != null) {
       inputstream.close();
     }
     if (datainputstream != null) {
       datainputstream.close();
     }
   } catch (Exception error) {
   }
 }

}</source>

Sort Fields

   <source lang="java">

import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.DataInputStream; import java.io.DataOutputStream; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.TextBox; import javax.microedition.lcdui.TextField; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordComparator; import javax.microedition.rms.RecordEnumeration; import javax.microedition.rms.RecordStore; import javax.microedition.rms.RecordStoreNotFoundException; public class SortFieldsMIDlet extends MIDlet implements CommandListener {

 private Command exitCommand = new Command("Exit", Command.EXIT, 1);
 private Display display;
 private String[] names = { "A", "B", "C", "D" };
 private int[] chineseScore = { 74, 98, 89, 76 };
 private int[] englishScore = { 67, 89, 89, 78 };
 private int[] mathScore = { 80, 76, 80, 78 };
 public SortFieldsMIDlet() {
   display = Display.getDisplay(this);
 }
 public void startApp() {
   TextBox aTextBox = new TextBox("Main", null, 256, TextField.ANY);
   RecordStore rs = null;
   boolean existingOrNot = false;
   existingOrNot = existing("aRS3");
   if (existingOrNot) {
     try {
       rs = RecordStore.openRecordStore("aRS3", false);
     } catch (Exception e) {
     }
   } else {
     try {
       rs = RecordStore.openRecordStore("aRS3", true);
     } catch (Exception e) {
     }
   }
   Student aStudent = null;
   try {
     for (int i = 0; i < names.length; i++) {
       aStudent = new Student();
       aStudent.write(names[i], chineseScore[i], englishScore[i], mathScore[i]);
       byte[] data = aStudent.changeToByteArray();
       int recordID = aStudent.getRecordID();
       if (recordID != -1) {
         rs.setRecord(recordID, data, 0, data.length);
       } else {
         recordID = rs.addRecord(data, 0, data.length);
         aStudent.setRecordID(recordID);
       }
       aStudent = null;
     }
     String result = "";
     aStudent = new Student();
     byte[] data;
     int number = 0;
     RecordComparator rc = new sortByAverage();
     RecordEnumeration re = rs.enumerateRecords(null, rc, false);
     while (re.hasNextElement()) {
       int recordID = re.nextRecordId();
       data = rs.getRecord(recordID);
       aStudent.changeFromByteArray(data);
       result += recordID + "\n" + "Name:" + aStudent.getName() + "\n" + ":"
           + aStudent.getChineseScore() + "\n" + ":" + aStudent.getEnglishScore() + "\n" + ":"
           + aStudent.getMathScore() + "\n";
       number++;
     }
     result += "" + number + "\n";
     aTextBox.setString(result);
     aTextBox.setString(result);
     aTextBox.addCommand(exitCommand);
     aTextBox.setCommandListener(this);
     display.setCurrent(aTextBox);
   } catch (Exception e) {
   }
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public boolean existing(String recordStoreName) {
   boolean existingOrNot = false;
   RecordStore rs = null;
   if (recordStoreName.length() > 32)
     return false;
   try {
     rs = RecordStore.openRecordStore(recordStoreName, false);
   } catch (RecordStoreNotFoundException e) {
     existingOrNot = false;
   } catch (Exception e) {
   } finally {
     try {
       rs.closeRecordStore();
     } catch (Exception e) {
     }
   }
   return existingOrNot;
 }
 public void commandAction(Command c, Displayable s) {
   destroyApp(false);
   notifyDestroyed();
 }

} class Student {

 private int ID = -1;
 private String name;
 private int chineseScore;
 private int englishScore;
 private int mathScore;
 public void write(String name, int chineseScore, int englishScore, int mathScore) {
   this.name = name;
   this.chineseScore = chineseScore;
   this.englishScore = englishScore;
   this.mathScore = mathScore;
 }
 public void setRecordID(int ID) {
   this.ID = ID;
 }
 public int getRecordID() {
   return ID;
 }
 public byte[] changeToByteArray() {
   byte[] data = null;
   try {
     ByteArrayOutputStream baos = new ByteArrayOutputStream();
     DataOutputStream dos = new DataOutputStream(baos);
     dos.writeUTF(name);
     dos.writeInt(chineseScore);
     dos.writeInt(englishScore);
     dos.writeInt(mathScore);
     data = baos.toByteArray();
     baos.close();
     dos.close();
   } catch (Exception e) {
   }
   return data;
 }
 public void changeFromByteArray(byte[] data) {
   try {
     ByteArrayInputStream bais = new ByteArrayInputStream(data);
     DataInputStream dis = new DataInputStream(bais);
     name = dis.readUTF();
     chineseScore = dis.readInt();
     englishScore = dis.readInt();
     mathScore = dis.readInt();
     bais.close();
     dis.close();
   } catch (Exception e) {
   }
 }
 public String getName() {
   return name;
 }
 public int getChineseScore() {
   return chineseScore;
 }
 public int getEnglishScore() {
   return englishScore;
 }
 public int getMathScore() {
   return mathScore;
 }

} class sortByAverage implements RecordComparator {

 public int compare(byte[] rec1, byte[] rec2) {
   DataInputStream student1 = new DataInputStream(new ByteArrayInputStream(rec1));
   DataInputStream student2 = new DataInputStream(new ByteArrayInputStream(rec2));
   int average1 = 0;
   int average2 = 0;
   try {
     average1 = (student1.readInt() + student1.readInt() + student1.readInt()) / 3;
     average2 = (student2.readInt() + student2.readInt() + student2.readInt()) / 3;
   } catch (Exception e) {
   }
   if (average1 == average2)
     return RecordComparator.EQUIVALENT;
   else if (average1 < average2)
     return RecordComparator.FOLLOWS;
   else
     return RecordComparator.PRECEDES;
 }

}</source>

Sort Mixed Record DataType

   <source lang="java">

import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.DataInputStream; import java.io.DataOutputStream; import javax.microedition.lcdui.Alert; import javax.microedition.lcdui.AlertType; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Form; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordComparator; import javax.microedition.rms.RecordEnumeration; import javax.microedition.rms.RecordStore; public class J2MESortMixedRecordDataTypeExample extends MIDlet implements CommandListener {

 private Display display;
 private Alert alert;
 private Form form = new Form("Mixed RecordEnumeration");
 private Command exit = new Command("Exit", Command.SCREEN, 1);
 private Command start = new Command("Start", Command.SCREEN, 1);
 private RecordStore recordstore = null;
 private RecordEnumeration recordEnumeration = null;
 private Comparator comparator = null;
 public J2MESortMixedRecordDataTypeExample() {
   display = Display.getDisplay(this);
   form.addCommand(exit);
   form.addCommand(start);
   form.setCommandListener(this);
 }
 public void startApp() {
   display.setCurrent(form);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public void commandAction(Command command, Displayable displayable) {
   if (command == exit) {
     destroyApp(true);
     notifyDestroyed();
   } else if (command == start) {
     try {
       recordstore = RecordStore.openRecordStore("myRecordStore", true);
       byte[] outputRecord;
       String outputString[] = { "Mary", "Bob", "Adam" };
       int outputInteger[] = { 15, 10, 5 };
       ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
       DataOutputStream outputDataStream = new DataOutputStream(outputStream);
       for (int x = 0; x < 3; x++) {
         outputDataStream.writeUTF(outputString[x]);
         outputDataStream.writeInt(outputInteger[x]);
         outputDataStream.flush();
         outputRecord = outputStream.toByteArray();
         recordstore.addRecord(outputRecord, 0, outputRecord.length);
         outputStream.reset();
       }
       outputStream.close();
       outputDataStream.close();
       String[] inputString = new String[3];
       byte[] byteInputData = new byte[300];
       ByteArrayInputStream inputStream = new ByteArrayInputStream(byteInputData);
       DataInputStream inputDataStream = new DataInputStream(inputStream);
       StringBuffer buffer = new StringBuffer();
       comparator = new Comparator();
       recordEnumeration = recordstore.enumerateRecords(null, comparator, false);
       while (recordEnumeration.hasNextElement()) {
         recordstore.getRecord(recordEnumeration.nextRecordId(), byteInputData, 0);
         buffer.append(inputDataStream.readUTF());
         buffer.append(inputDataStream.readInt());
         buffer.append("\n");
         inputDataStream.reset();
       }
       alert = new Alert("Reading", buffer.toString(), null, AlertType.WARNING);
       alert.setTimeout(Alert.FOREVER);
       display.setCurrent(alert);
       inputDataStream.close();
       inputStream.close();
       recordstore.closeRecordStore();
       if (RecordStore.listRecordStores() != null) {
         RecordStore.deleteRecordStore("myRecordStore");
         comparator.rupareClose();
         recordEnumeration.destroy();
       }
     } catch (Exception error) {
       alert = new Alert("Error Removing", error.toString(), null, AlertType.WARNING);
       alert.setTimeout(Alert.FOREVER);
       display.setCurrent(alert);
     }
   }
 }

} class Comparator implements RecordComparator {

 private byte[] comparatorInputData = new byte[300];
 private ByteArrayInputStream comparatorInputStream = null;
 private DataInputStream comparatorInputDataType = null;
 public int compare(byte[] record1, byte[] record2) {
   int record1int, record2int;
   try {
     int maxlen = Math.max(record1.length, record2.length);
     if (maxlen > comparatorInputData.length) {
       comparatorInputData = new byte[maxlen];
     }
     comparatorInputStream = new ByteArrayInputStream(record1);
     comparatorInputDataType = new DataInputStream(comparatorInputStream);
     comparatorInputDataType.readUTF();
     record1int = comparatorInputDataType.readInt();
     comparatorInputStream = new ByteArrayInputStream(record2);
     comparatorInputDataType = new DataInputStream(comparatorInputStream);
     comparatorInputDataType.readUTF();
     record2int = comparatorInputDataType.readInt();
     if (record1int == record2int) {
       return RecordComparator.EQUIVALENT;
     } else if (record1int < record2int) {
       return RecordComparator.PRECEDES;
     } else {
       return RecordComparator.FOLLOWS;
     }
   } catch (Exception error) {
     return RecordComparator.EQUIVALENT;
   }
 }
 public void compareClose() {
   try {
     if (comparatorInputStream != null) {
       comparatorInputStream.close();
     }
     if (comparatorInputDataType != null) {
       comparatorInputDataType.close();
     }
   } catch (Exception error) {
   }
 }

}</source>

Sort records in RecordStore

   <source lang="java">

import javax.microedition.lcdui.Alert; import javax.microedition.lcdui.AlertType; import javax.microedition.lcdui.rumand; import javax.microedition.lcdui.rumandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Form; import javax.microedition.midlet.MIDlet; import javax.microedition.rms.RecordComparator; import javax.microedition.rms.RecordEnumeration; import javax.microedition.rms.RecordStore; public class J2MESortExample extends MIDlet implements CommandListener {

 private Display display;
 private Alert alert;
 private Form form = new Form("Mixed RecordEnumeration", null);
 private Command exit = new Command("Exit", Command.SCREEN, 1);
 private Command start = new Command("Start", Command.SCREEN, 1);
 private RecordStore recordstore = null;
 private RecordEnumeration recordEnumeration = null;
 private Comparator comparator = null;
 public J2MESortExample() {
   display = Display.getDisplay(this);
   form.addCommand(exit);
   form.addCommand(start);
   form.setCommandListener(this);
 }
 public void startApp() {
   display.setCurrent(form);
 }
 public void pauseApp() {
 }
 public void destroyApp(boolean unconditional) {
 }
 public void commandAction(Command command, Displayable displayable) {
   if (command == exit) {
     destroyApp(true);
     notifyDestroyed();
   } else if (command == start) {
     try {
       recordstore = RecordStore.openRecordStore("myRecordStore", true);
       String outputData[] = { "M", "B", "A" };
       for (int x = 0; x < 3; x++) {
         byte[] byteOutputData = outputData[x].getBytes();
         recordstore.addRecord(byteOutputData, 0, byteOutputData.length);
       }
       StringBuffer buffer = new StringBuffer();
       Comparator comparator = new Comparator();
       recordEnumeration = recordstore.enumerateRecords(null, comparator, false);
       while (recordEnumeration.hasNextElement()) {
         buffer.append(new String(recordEnumeration.nextRecord()));
         buffer.append("\n");
       }
       alert = new Alert("Reading", buffer.toString(), null, AlertType.WARNING);
       alert.setTimeout(Alert.FOREVER);
       display.setCurrent(alert);
       recordstore.closeRecordStore();
       if (RecordStore.listRecordStores() != null) {
         RecordStore.deleteRecordStore("myRecordStore");
         recordEnumeration.destroy();
       }
     } catch (Exception error) {
       alert = new Alert("Error Removing", error.toString(), null, AlertType.WARNING);
       alert.setTimeout(Alert.FOREVER);
       display.setCurrent(alert);
     }
   }
 }

} class Comparator implements RecordComparator {

 public int compare(byte[] record1, byte[] record2) {
   String string1 = new String(record1), string2 = new String(record2);
   int comparison = string1.rupareTo(string2);
   if (comparison == 0)
     return RecordComparator.EQUIVALENT;
   else if (comparison < 0)
     return RecordComparator.PRECEDES;
   else
     return RecordComparator.FOLLOWS;
 }

}</source>