Randomizing recordStore

Question

hi,
im having this peculiar problem.
Aim: Extracting a record randomly from a RecordStore with every record gaving almost equal probability of being returned.
        try
            numRecs = myDatabase.getNumRecords();
        catch (RecordStoreException rse)
             System.out.println(rse);
             rse.printStackTrace();
        System.out.println("There are " + numRecs + " records in the record store");
        if(numRecs != 0)
            try
                int someNumber = (int) rand.nextInt() % numRecs;
                recordToBeReturned = new String(myDatabase.getRecord(someNumber));
            catch(RecordStoreNotOpenException rsnoe)
                System.out.println("The record store is not open");
                rsnoe.printStackTrace();
            catch(InvalidRecordIDException irie)
                System.out.println("The Record ID is invalid");
                irie.printStackTrace();
            catch (RecordStoreException rse)
                 System.out.println("There has been a general exception");
                 rse.printStackTrace();
Problem: the "getRecord()" method throws up an Arithmetic Exception. i even tried using the variant of getRecord(int, byte[],int). still no use.
So, could anyone suggest a way to randomize using RecordComparator so that i can retrieve random records with enumerate().
thanx in advance.
=====
kiran

Answer 1

hey guyz,
i finally hit upon a solution which seems rather crude.
but im not sure whether the probablity for each record is almost equal...please help me analyze this..here is the code fragment:
public class Database implements RecordComparator{
public synchronized RecordEnumeration enumerate() throws RecordStoreNotOpenException
       return myDatabase.enumerateRecords(null, this, true);
    public Record getARecord()
        Record recordToBeReturned = new Record();
        int numRecs = 0;
        int someID = 0;
         /* class Record is defined as follows:
           *  class Record
           *         String actualRecord;
           *        int  recordID;
        try
            RecordEnumeration rEnum = this.enumerate();
            if(rEnum.hasNextElement() == false)
                rEnum.reset();
            recordToBeReturned.actualRecord = new String(rEnum.nextRecord());
            recordToBeReturned.recordId = rEnum.nextRecordId();
       //CATCH EXCEPTIONS HERE
       *generate a random number between -1 and 1.
       * so this method will randomly oscillate between
       * EQUIVALENT, PRECEDES AND FOLLOWS
    public int compare(byte [] rec1, byte [] rec2)
        Random rand = new Random();
        int randomNumber = (int) rand.nextInt() % 3;
        return randomNumber - 1;
}