Sort Mixed Record Data Type Example
/*
J2ME: The Complete Reference
James Keogh
Publisher: McGraw-Hill
ISBN 0072227109
*/
//jad file (please verify the jar size)
/*
MIDlet-Name: SortMixedRecordDataTypeExample
MIDlet-Version: 1.0
MIDlet-Vendor: MyCompany
MIDlet-Jar-URL: SortMixedRecordDataTypeExample.jar
MIDlet-1: SortMixedRecordDataTypeExample, ,
SortMixedRecordDataTypeExample
MicroEdition-Configuration: CLDC-1.0
MicroEdition-Profile: MIDP-1.0
MIDlet-JAR-SIZE: 100
*/
import javax.microedition.rms.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;
import java.io.*;
public class SortMixedRecordDataTypeExample
extends MIDlet implements CommandListener
{
private Display display;
private Alert alert;
private Form form;
private Command exit;
private Command start;
private RecordStore recordstore = null;
private RecordEnumeration recordEnumeration = null;
private Comparator comparator = null;
public SortMixedRecordDataTypeExample ()
{
display = Display.getDisplay(this);
exit = new Command("Exit", Command.SCREEN, 1);
start = new Command("Start", Command.SCREEN, 1);
form = new Form("Mixed RecordEnumeration");
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
{
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();
}
catch ( Exception error)
{
alert = new Alert("Error Writing",
error.toString(), null, AlertType.WARNING);
alert.setTimeout(Alert.FOREVER);
display.setCurrent(alert);
}
try
{
String[] inputString = new String[3];
int z = 0;
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();
}
catch (Exception error)
{
alert = new Alert("Error Reading",
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");
comparator.compareClose();
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)
{
}
}
}
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