RMS -- Getting the RecordId of the Current Record

Question

Hello, I need to get the current record Id from recordStore so I can update a count field. Here is the code that updates the count field.
// member vars to hold RMS stuff
private RecordStore rs;
private RecordEnumeration re;
private ByteArrayOutputStream os;
// Constructor allocates RMS vars
public Ctor ( String sRmsFilename ) throws Exception {
rs = RecordStore.openRecordStore ( sRmsFilename, false );
re = rs.enumerateRecords ( null, null, true );
re.keepUpdated ( true );
os = new ByteArrayOutputStream ();
////// METHOD REQUIRING CURRENT RECORD ID
private void updateDBCount ( int count ) throws Exception {
DataOutputStream dos = new DataOutputStream ( os ) ;
dos.writeInt ( count );
*int currentRecordId = {color:#008080}getCurrentRecordId {color}();*
byte[] b = os.toByteArray ();
os.reset ();
rs.setRecord ( currentRecordId, b, 0, b.length );
This is the code that I use to retrieve the recordId of the current record;
////////// CODE TO RETRIEVE CURENT RECORD ID
private int getCurrentRecordId () throws Exception {
*if ( re.{color:#0000ff}hasPreviousElement{color} () ) {*
*re.{color:#0000ff}previousRecordId{color} ();*
*return re.{color:#0000ff}nextRecordId{color} ();*
*else {*
*re.{color:#0000ff}nextRecordId{color} ();*
*return re.{color:#0000ff}previousRecordId{color} ();*
This is how getCurrentRecordId () is suppose to work, using RecordEnumeration. If there is a previous record then advance backwards to previous record. Now advance forward to next record and this should been the current record Id and so it is return. However, if there is no previous record then advance forward to next record. Now advanced backward to previous record and this should been the current record Id and so it is return.
Well, does anyone see a problem with this code? If so please let me know and, of course, as always any suggestions are very welcome!
Note: The reason I chose to use RecordEnumeration.nextRecordId () / previousRecordId () methods is because I figured it is run fast and less resources would be consumed than if actual records were retrieved using RecordEnumeration.nextRecord () / previousRecord ()methods.
Thanks!

Answer 1

{color:#000080}I see a problem if the RecordStore has no records, or only one record. This is what I might do (untested)private int getCurrentRecordId () throws Exception
    if ( re.numRecords() == 0 )
        // maybe you want to add a record
        // or maybe throw a new Exception
        // or just return -1 or 0 and
        // let the calling routine handle that
        return -1;
    } else if ( re.numRecords() ==1 )
        return 1;
    } else if ( re.hasPreviousElement () )
        re.previousRecordId ();
        return re.nextRecordId ();
    } else
        re.nextRecordId ();
        return re.previousRecordId ();
}Regarding running fast, the documentation for javax.microedition.rms.RecordEnumeration says{color}
keepUpdated - if true, the enumerator will keep its enumeration current with any changes in the records of the record store. Use with caution as there are possible performance consequences.{color:#000080}
Actually, since you do not have a filter or comparator, it would probably be more efficient to keep track of the current record with a int instance field. But that's your choice.
Cheers, Darryl{color}