Answer / mohit chaudhry

package hello;
import javax.microedition.rms.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class ReadWrite extends MIDlet implements CommandListener,RecordListener
{
private RecordStore rs = null;
RecordEnumeration re=null;
Display disp;
Alert a1,a2;
List l1,l2;
Form f,f1;
TextField tf,tf1;
Command edit,delete,back,go,ok;
public ReadWrite()
{
disp=Display.getDisplay(this);
a1=new Alert("Result");
a2=new Alert("Listener Result");
edit=new Command("Edit",Command.SCREEN,1);
delete=new Command("Delete",Command.SCREEN,2);
back=new Command("Back",Command.BACK,3);
ok=new Command("Ok",Command.OK,1);
go=new Command("Go",Command.OK,1);
l1=new List("Main Screen",List.IMPLICIT);
l2=new List("Contacts",List.IMPLICIT);
l1.append("Read", null);
l1.append("Write", null);
l1.append("Exit", null);
l1.addCommand(ok);
l2.addCommand(delete);
l2.addCommand(edit);
l2.addCommand(back);
l1.setCommandListener(this);
l2.setCommandListener(this);
f=new Form("Add Record");
tf=new TextField("Enter Data","",50,TextField.ANY);
f.append(tf);
f.addCommand(go);
f.setCommandListener(this);
try
{
rs = RecordStore.openRecordStore("data", true );

rs.addRecordListener(this);
}
catch (Exception e)
{ }
}
public void commandAction(Command c,Displayable d)
{
String s=l1.getString(l1.getSelectedIndex());
if(c==ok && s.equals("Read"))
{
l2.deleteAll();
try
{
re= rs.enumerateRecords(null, null, true);
while( re.hasNextElement() ){
byte[] data = re.nextRecord();
l2.append(new String(data), null);
}
disp.setCurrent(l2);
}
catch (Exception e)
{ }
}
if(c==ok && s.equals("Write"))
{
tf.setString(" ");
disp.setCurrent(f);
}
if(c==ok && s.equals("Exit"))
{
destroyApp(false);
notifyDestroyed();
try
{
rs.closeRecordStore();
RecordStore.deleteRecordStore("db");
}
catch (Exception e)
{ }
}
if(c==delete)
{
try
{
re = rs.enumerateRecords(null, null, true);
if (re.hasNextElement())
{
int recordId = re.nextRecordId();
rs.deleteRecord(recordId);

}
}
catch (Exception ex)
{ }
}
if(c==edit)
{
disp.setCurrent(f1);

}

if(c==back)
{
disp.setCurrent(l1);
}
if(c==go)
{
byte[] rec = tf.getString().getBytes();
try
{
rs.addRecord(rec, 0, rec.length);
tf.setString("");
}
catch (Exception e)
{ }

}

}

public void destroyApp( boolean unconditional )
{}

public void startApp()
{
disp.setCurrent(l1);
}

public void pauseApp()
{ }

public void recordAdded(RecordStore r,int rid)
{

a2.setString("record listener called for record add");
disp.setCurrent(a2,l1);
}

public void recordDeleted(RecordStore r,int rid)
{

a2.setString("record listener called for record delete");
disp.setCurrent(a2,l1);
}
public void recordChanged(RecordStore r,int rid)
{

a2.setString("record listener called for record chsnge");
disp.setCurrent(a2,l1);
}
}

Answer / binukjames

Following is a simple J2ME Record store program.
Create a project(MIDet) using this code and see the console
output.
The same way u can store / update ur data into RMS(Record
Management Systen _mobile database). create a user interface
for this program if required.

//===RmsListener.java ============================START

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

public class RmsListener extends MIDlet
{
private RecordStore rs = null;
static final String REC_STORE = "db_8";

public RmsListener()
{
// Open record store and add listener
openRecStore();
rs.addRecordListener(new TestRecordListener());

// Initiate actions that will wake up the listener
writeRecord("J2ME and MIDP");
updateRecord("MIDP and J2ME");
deleteRecord();

closeRecStore(); // Close record store
deleteRecStore(); // Remove the record store
}

public void destroyApp( boolean unconditional )
{
}

public void startApp()
{
// There is no user interface, go ahead and shutdown
destroyApp(false);
notifyDestroyed();
}

public void pauseApp()
{
}

public void openRecStore()
{
try
{
// The second parameter indicates that the record store
// should be created if it does not exist
rs = RecordStore.openRecordStore(REC_STORE, true);
}
catch (Exception e)
{
db(e.toString());
}
}

public void closeRecStore()
{
try
{
rs.closeRecordStore();
}
catch (Exception e)
{
db(e.toString());
}
}

public void deleteRecStore()
{
if (RecordStore.listRecordStores() != null)
{
try
{
RecordStore.deleteRecordStore(REC_STORE);
}
catch (Exception e)
{
db(e.toString());
}
}
}

public void writeRecord(String str)
{
byte[] rec = str.getBytes();

try
{
rs.addRecord(rec, 0, rec.length);
}
catch (Exception e)
{
db(e.toString());
}
}

public void updateRecord(String str)
{
try
{
rs.setRecord(1, str.getBytes(), 0, str.length());
}
catch (Exception e)
{
db(e.toString());
}
}

public void deleteRecord()
{
try
{
rs.deleteRecord(1);
}
catch (Exception e)
{
db(e.toString());
}
}

/*--------------------------------------------------
* Simple message to console for debug/errors
* When used with Exceptions we should handle the
* error in a more appropriate manner.
*-------------------------------------------------*/
public void db(String str)
{
System.err.println("Msg: " + str);
}

}


/*--------------------------------------------------
* Listen for updates to the record store
*-------------------------------------------------*/
class TestRecordListener implements RecordListener
{
public void recordAdded(RecordStore recordStore, int
recordId)
{
try
{
System.out.println("Record with ID#: " + recordId +
" added to RecordStore: " +
recordStore.getName());
}
catch (Exception e)
{
System.err.println(e);
}
}

public void recordDeleted(RecordStore recordStore, int
recordId)
{
try
{
System.out.println("Record with ID#: " + recordId +
" deleted from RecordStore: " +
recordStore.getName());
}
catch (Exception e)
{
System.err.println(e);
}
}

public void recordChanged(RecordStore recordStore, int
recordId)
{
try
{
System.out.println("Record with ID#: " + recordId +
" changed in RecordStore: " +
recordStore.getName());
}
catch (Exception e)
{
System.err.println(e);
}
}
}
//=====================================================END

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