Testing the connection

[Jens Mayer <je...@gmx.de>]

In my application, the user has the ability to switch between databases 
(for testing purposes). He gets a little dialog, types in 
user/password/db-name and under the hood, an appropriate
DataContext is built.

Works fine, but I want to test the correctness of what he typed in 
BEFORE the next query is performed.

So I could do that by getting the new DataSource and invoking 
getConnection() with an appropriate Exceptionhandling but that seems to 
be not very smart design.

Does anyone have a better idea?

Jens

Re: Testing the connection

[Mike Kienenberger <mk...@gmail.com>]

What you described is how the Cayenne modeler does it, so it's
probably the best way we know.

org.objectstyle.cayenne.modeler.dialog.pref.DataSourcePreferences

    /**
     * Tries to establish a DB connection, reporting the status of
this operation.
     */
    public void testDataSourceAction() {
        DBConnectionInfo currentDataSource = getConnectionInfo();
        if (currentDataSource == null) {
            return;
        }

        if (currentDataSource.getJdbcDriver() == null) {
            JOptionPane.showMessageDialog(
                    null,
                    "No JDBC Driver specified",
                    "Warning",
                    JOptionPane.WARNING_MESSAGE);
            return;
        }

        if (currentDataSource.getUrl() == null) {
            JOptionPane.showMessageDialog(
                    null,
                    "No Database URL specified",
                    "Warning",
                    JOptionPane.WARNING_MESSAGE);
            return;
        }

        try {
            Class driverClass =
getApplication().getClassLoadingService().loadClass(
                    currentDataSource.getJdbcDriver());
            Driver driver = (Driver) driverClass.newInstance();

            // connect via Cayenne DriverDataSource - it addresses
some driver issues...
            Connection c = new DriverDataSource(
                    driver,
                    currentDataSource.getUrl(),
                    currentDataSource.getUserName(),
                    currentDataSource.getPassword()).getConnection();
            try {
                c.close();
            }
            catch (SQLException e) {
                // i guess we can ignore this...
            }

            JOptionPane.showMessageDialog(
                    null,
                    "Connected Successfully",
                    "Success",
                    JOptionPane.INFORMATION_MESSAGE);
        }
        catch (Throwable th) {
            th = Util.unwindException(th);
            JOptionPane.showMessageDialog(null, "Error connecting to DB: "
                    + th.getLocalizedMessage(), "Warning",
JOptionPane.WARNING_MESSAGE);
            return;
        }
    }



On 4/10/07, Jens Mayer <je...@gmx.de> wrote:
> In my application, the user has the ability to switch between databases
> (for testing purposes). He gets a little dialog, types in
> user/password/db-name and under the hood, an appropriate
> DataContext is built.
>
> Works fine, but I want to test the correctness of what he typed in
> BEFORE the next query is performed.
>
> So I could do that by getting the new DataSource and invoking
> getConnection() with an appropriate Exceptionhandling but that seems to
> be not very smart design.
>
> Does anyone have a better idea?
>
> Jens
>