Clone Method Example (VJ++)

Clone Method Example (VJ++)

This example uses the Clone method to create copies of a Recordset and then lets the user position the record pointer of each copy independently.

import com.ms.wfc.data.*;
import java.io.* ;

public class CloneX
{
    // The main entry point for the application.

    public static void main (String[] args)
    {
        CloneX();
        System.exit(0);
    }

    // CloneX function

    static void CloneX()
    {
        // Assign SQL statement and connection string to variables.
        String strSQL = "SELECT stor_name FROM Stores "
            + "ORDER BY stor_name";

        String strCnn = "Provider=sqloledb;Data Source=srv;"
            + "Initial Catalog=Pubs;User Id=sa;Password=;";

        // Define ADO Objects.
        Recordset[] arstStores = null;

        //Declarations.
        BufferedReader in =
            new BufferedReader (new InputStreamReader(System.in));
        String line = null;
        String strMessage;
        String strFind;
        int  intLoop;
        boolean booExit = true;

        try
        {
            // Open recordset as a static cursor type recordset.
            arstStores = new Recordset[3];
            arstStores[0] = new Recordset();
            arstStores[0].setCursorType(AdoEnums.CursorType.STATIC);
            arstStores[0].setLockType(AdoEnums.LockType.BATCHOPTIMISTIC);
            arstStores[0].open(strSQL,strCnn,AdoEnums.CursorType.STATIC,
                AdoEnums.LockType.BATCHOPTIMISTIC,AdoEnums.CommandType.TEXT);

            // Create two clones of the original Recordset.
            arstStores[1] = (Recordset)arstStores[0].clone
                (AdoEnums.LockType.BATCHOPTIMISTIC);
            arstStores[2] = (Recordset)arstStores[0].clone
                (AdoEnums.LockType.BATCHOPTIMISTIC);

            while(booExit)
            {
                // Loop through the array so that on each pass,
                // the user is searching a different copy of the
                // same Recordset.
                for (intLoop = 0; intLoop < 3; intLoop++)
                {
                    // Ask for search string while showing where
                    // the current record pointer is for each Recordset
                    strMessage = "\nRecordsets from stores table:" + "\n"
                        +  "  1 - Original - Record pointer at "
                        + arstStores[0].getField("stor_name").getString()
                        + "\n" + "  2 - Clone - Record pointer at "
                        + arstStores[1].getField("stor_name").getString()
                        + "\n" + "  3 - Clone - Record pointer at "
                        + arstStores[2].getField("stor_name").getString()
                        + "\n";
                    System.out.println(strMessage);
                    System.out.println("Enter search string for #"
                        + (intLoop+1) + "(Press <Enter> to Exit.)");

                    if((strFind = in.readLine().trim()) == null)
                    {
                        booExit = false;
                        break;
                    }

                    // Find the search string; if there's no
                    // match, jump to the last record.
                    arstStores[intLoop].setFilter("stor_name >= '" +
                        strFind + "'");
                    if (arstStores[intLoop].getEOF())
                    {
                        arstStores[intLoop].setFilter
                            (new Integer(AdoEnums.FilterGroup.NONE));
                        arstStores[intLoop].moveLast();
                    }
                }
            }
            // Cleanup objects before exit.
            arstStores[0].close();
            arstStores[1].close();
            arstStores[2].close();
        }
        catch( AdoException ae )
        {
            // Notify user of any errors that result from ADO.

            // As passing a connection, check for null pointer first.
            if (arstStores[0] != null)
            {
                PrintProviderError(arstStores[0].getActiveConnection());
            }
            else
            {
                System.out.println("Exception: " + ae.getMessage());
            }
        }

        // System read requires this catch.
        catch( java.io.IOException je)
        {
            PrintIOError(je);
        }

    }

    // PrintProviderError Function

    static void PrintProviderError( Connection Cnn1 )
    {
        // Print Provider errors from Connection object.
        // ErrItem is an item object in the Connection’s Errors collection.
        com.ms.wfc.data.Error  ErrItem = null;
        long nCount = 0;
        int  i      = 0;

        nCount = Cnn1.getErrors().getCount();

        // If there are any errors in the collection, print them.
        if( nCount > 0);
        {
            // Collection ranges from 0 to nCount - 1
            for (i = 0; i< nCount; i++)
            {
                ErrItem = Cnn1.getErrors().getItem(i);
                System.out.println("\t Error number: " + ErrItem.getNumber()
                    + "\t" + ErrItem.getDescription() );
            }
        }

    }

    // PrintIOError Function

    static void PrintIOError( java.io.IOException je)
    {
        System.out.println("Error \n");
        System.out.println("\tSource = " + je.getClass() + "\n");
        System.out.println("\tDescription = " + je.getMessage() + "\n");
    }
}