JAVA Swing client, Data Access to Remote Database; Ibatis

By : poezn
Source: Stackoverflow.com
Question!

I've got a Java client that needs to access a remote database. It is the goal to hide database credentials from the user and not hardcode any credentials within the code. Therefore, the database access will probably have to be on the server side.

I'm restricted to use Ibatis as a data abstraction framework. Apart from that I have JBoss running on the webserver, allowing me to use data sources.

How would you design the remote database access and data serialization/deserialization. would you prefer web services of some kind of data stream over a socket? How would you realize either of both?

By : poezn


Answers

Build a Service Layer and expose it over RMI - possibly as EJB3 stateless session beans as you have JBoss, possibly as pure RMI. I wouldn't bother with web services unless you have a specific need. RMI will take case of serialisation for you.

Your service layer needs to expose a method to authenticate users using their credentials entered on startup of the Swing app. All calls for data go through the service layer. No SQL exists in the Swing app.

There are other benfits of this arrangment other than just hiding the database credentials. Not only do you end up with a layered architecture, but you gain efficiencies from sharing prepared statements amongst all your clients by having a single data source on the server.



FWIW, here's my implementation of manually setting orientation (to go in your app's root view controller, natch):

-(void)rotateInterfaceToOrientation:(UIDeviceOrientation)orientation{

    CGRect bounds = [[ UIScreen mainScreen ] bounds ];
    CGAffineTransform t;
    CGFloat r = 0;
    switch ( orientation ) {
        case UIDeviceOrientationLandscapeRight:
            r = -(M_PI / 2);
            break;
        case UIDeviceOrientationLandscapeLeft:
            r  = M_PI / 2;
            break;
    }
    if( r != 0 ){
        CGSize sz = bounds.size;
        bounds.size.width = sz.height;
        bounds.size.height = sz.width;
    }
    t = CGAffineTransformMakeRotation( r );

    UIApplication *application = [ UIApplication sharedApplication ];

    [ UIView beginAnimations:@"InterfaceOrientation" context: nil ];
    [ UIView setAnimationDuration: [ application statusBarOrientationAnimationDuration ] ];
    self.view.transform = t;
    self.view.bounds = bounds;
    [ UIView commitAnimations ];

    [ application setStatusBarOrientation: orientation animated: YES ];     
}

coupled with the following UINavigationControllerDelegate method (assuming you're using a UINavigationController):

-(void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated{
    // rotate interface, if we need to
    UIDeviceOrientation orientation = [[ UIDevice currentDevice ] orientation ];
    BOOL bViewControllerDoesSupportCurrentOrientation = [ viewController shouldAutorotateToInterfaceOrientation: orientation ];
    if( !bViewControllerDoesSupportCurrentOrientation ){
        [ self rotateInterfaceToOrientation: UIDeviceOrientationPortrait ];
    }
}

That takes care of rotating the root view according to whether an incoming UIViewController supports the current device orientation. Finally, you'll want to hook up rotateInterfaceToOrientation to actual device orientation changes in order to mimic standard iOS functionality. Add this event handler to the same root view controller:

-(void)onUIDeviceOrientationDidChangeNotification:(NSNotification*)notification{
    UIViewController *tvc = self.rootNavigationController.topViewController;
    UIDeviceOrientation orientation = [[ UIDevice currentDevice ] orientation ];
    // only switch if we need to (seem to get multiple notifications on device)
    if( orientation != [[ UIApplication sharedApplication ] statusBarOrientation ] ){
        if( [ tvc shouldAutorotateToInterfaceOrientation: orientation ] ){
            [ self rotateInterfaceToOrientation: orientation ];
        }
    }
}

Finally, register for UIDeviceOrientationDidChangeNotification notifications in init or loadview like so:

[[ NSNotificationCenter defaultCenter ] addObserver: self
                                           selector: @selector(onUIDeviceOrientationDidChangeNotification:)
                                               name: UIDeviceOrientationDidChangeNotification
                                             object: nil ];
[[ UIDevice currentDevice ] beginGeneratingDeviceOrientationNotifications ];


This video can help you solving your question :)
By: admin