Simple Sort for RMS
/*--------------------------------------------------
* SimpleSort.java
*
* No GUI interface, all output is to the console
*
* Example from the book: Core J2ME Technology
* Copyright John W. Muchow http://www.CoreJ2ME.com
* You may use/modify for any non-commercial purpose
*-------------------------------------------------*/
import java.io.*;
import javax.microedition.midlet.*;
import javax.microedition.rms.*;
public class SimpleSort extends MIDlet
{
private RecordStore rs = null;
static final String REC_STORE = "db_1";
public SimpleSort()
{
openRecStore(); // Create the record store
// Write a few records
writeRecord("Sand Wedge");
writeRecord("One Wood");
writeRecord("Putter");
writeRecord("Five Iron");
// Read back with enumerator, sorting the results
readRecords();
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 readRecords()
{
try
{
if (rs.getNumRecords() > 0)
{
Comparator comp = new Comparator();
RecordEnumeration re = rs.enumerateRecords(null, comp, false);
while (re.hasNextElement())
{
// Calls String constructor that takes an array of bytes as input
String str = new String(re.nextRecord());
System.out.println(str);
System.out.println("------------------------------");
}
}
}
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.
*-------------------------------------------------*/
private void db(String str)
{
System.err.println("Msg: " + str);
}
}
/*--------------------------------------------------
* Compares two records to determine sort order
*-------------------------------------------------*/
class Comparator implements RecordComparator
{
public int compare(byte[] rec1, byte[] rec2)
{
String str1 = new String(rec1), str2 = new String(rec2);
int result = str1.compareTo(str2);
if (result == 0)
return RecordComparator.EQUIVALENT;
else if (result < 0)
return RecordComparator.PRECEDES;
else
return RecordComparator.FOLLOWS;
}
}
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