Handling Errors in Visual J++

Handle ADO errors in your Microsoft Visual J++ applications using a try catch block. Once an error has been thrown, you can iterate through the collection, successively handling each error. The following Visual J++ example shows a console application that deliberately causes an error.

When the catch block is activated, it calls the PrintProviderError function to display the errors. The PrintProviderError function iterates through the Errors collection and sends a line to the standard output device that describes each error in the collection.

// BeginErrorExampleVJ
/**
 * This class can take a variable number of parameters on the command
 * line. Program execution begins with the main() method. The class
 * constructor is not invoked unless an object of type 'Class1'
 * created in the main() method.
 */

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

public class ErrorExample
{
    /**
     * The main entry point for the application. 
     *
     * @param args Array of parameters passed to the application
     * via the command line.
     */
    public static void main (String[] args)
    {
        DescriptionX();
        System.exit(0);
    }

    static void DescriptionX()
    {
        BufferedReader in = new 
        BufferedReader(new InputStreamReader(System.in));

        // Define ADO Objects.
        Connection cnConn1 = null;

        try
        {
            // Create an error by trying to
            // Open a database that doesn't exist.
            cnConn1 = new Connection();
            cnConn1.open("nothing");
        }
        catch( AdoException ae )
        {
            // Notify user of any errors that result from ADO.
            PrintProviderError(cnConn1);
        }

        try
        {
            System.out.println("\nPress <Enter> key to continue.");
            in.readLine();
        }
        // 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 Connections 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");
    }
}
// EndErrorExampleVJ