courier.java

J2ME MIDP_Example_Applications

// Copyright 2002 Nokia Corporation. 
// 
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// EXPRESS OR IMPLIED, INCLUDING ANY WARRANTY OF MERCHANTABILITY, FITNESS 
// FOR ANY PARTICULAR PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE 
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// OF ANY PATENT OR OTHER INTELLECTUAL PROPERTY RIGHTS OWNED OR CONTROLLED 
// BY THIRD PARTIES 
// 
// Furthermore, information provided in this source code is preliminary, 
// and may be changed substantially prior to final release. Nokia Corporation 
// retains the right to make changes to this source code at 
// any time, without notice. This source code is provided for informational 
// purposes only. 
// 
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// Corporation.
// Java and all Java-based marks are trademarks or registered trademarks of
// Sun Microsystems, Inc.
// Other product and company names mentioned herein may be trademarks or
// trade names of their respective owners.
// 
// A non-exclusive, non-transferable, worldwide, limited license is hereby 
// granted to the Licensee to download, print, reproduce and modify the 
// source code. The licensee has the right to market, sell, distribute and 
// make available the source code in original or modified form only when 
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package example.delivery;

import java.util.*;
import javax.microedition.rms.*;


// The Courier class is a singleton which wraps the 'Courier'
// record store. There are two records in that record store.
// After the records are first created in the new
// record store, no new records are ever added. So the recordIds
// always have known fixed values between 1 and 2.
// See the recordId index values defined below.


public class Courier
{
    // recordId's for USERNAME and PASSWORD
    private static final int USERNAME = 1;
    private static final int PASSWORD = 2;
    private static final byte[] empty = new byte[0];
    public  static final String RSNAME = "Courier";
    private static RecordStore rs = null;
    private static Courier instance = null;

    // The unique singleton instance of this class.

    static Courier getInstance()
        throws RecordStoreException
    {
        if (instance == null)
        {
            instance = new Courier();
        }
        return instance;
    }


    private Courier()
        throws RecordStoreException
    {
        openRecordStore();
        if (rs.getNumRecords() == 0)
        {
            init(null, null);
        }
    }


    static void openRecordStore()
        throws RecordStoreException
    {
        // At most, one rs should ever be open.
        if (rs == null)
        {
            rs = RecordStore.openRecordStore(RSNAME, true);
        }
    }


    static void closeRecordStore()
        throws RecordStoreException
    {
        if (rs != null)
        {
            rs.closeRecordStore();
            rs = null;
        }
    }


    // Method newRecordStore can also be used to delete all records too.

    private void newRecordStore()
        throws RecordStoreException
    {
        // Note: To perform a deleteRecordStore, rs should first be closed as
        //       many times as it was opened. In this class, that's at most once.

        closeRecordStore();
        try
        {
            RecordStore.deleteRecordStore(RSNAME);
        }
        catch(RecordStoreNotFoundException e)
        {
            // It may not exist the first time newRecordStore is called.
        }
        openRecordStore();
    }


    private void init(String username, String password)
        throws RecordStoreException
    {
        // The method adds records to the record store in the order that
        // matches the fixed recordId values defined above.

        newRecordStore();
        addRecord(username); // recordId USERNAME (1)
        addRecord(password); // recordId PASSWORD (2)
    }


    String getUsername()
        throws RecordStoreException
    {
        byte[] barray = rs.getRecord(USERNAME);
        if (barray == null || barray.length == 0)
        {
            return "";
        }
        else
        {
            return new String(barray);
        }
    }


    void setUsername(String str)
        throws RecordStoreException
    {
        setRecord(USERNAME, str);
    }


    String getPassword()
        throws RecordStoreException
    {
        byte[] barray = rs.getRecord(PASSWORD);
        if (barray == null || barray.length == 0)
        {
            return "";
        }
        else
        {
            return new String(barray);
        }
    }


    void setPassword(String str)
        throws RecordStoreException
    {
        setRecord(PASSWORD, str);
    }


    private void addRecord(String str)
        throws RecordStoreException
    {
        if (str == null || str.length() == 0)
        {
            rs.addRecord(null, 0, 0);
        }
        else
        {
            rs.addRecord(str.getBytes(), 0, str.length());
        }
    }


    private void setRecord(int ix, String str)
        throws RecordStoreException
    {
        if (str == null || str.length() == 0)
        {
            rs.setRecord(ix, empty, 0, 0);
        }
        else
        {
            rs.setRecord(ix, str.getBytes(), 0, str.length());
        }
    }
}