Swing Application Hangups (Garbage Collection?)

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2 total messages Started by Adrian Pitulac Sat, 03 Jan 2004 13:32

#1315

Author: Adrian Pitulac
Date: Sat, 03 Jan 2004 13:32

37 lines
2193 bytes

Hello,

i have a problem with one of my applications which seems to hangup. i have
looked with optimizeit on the app and it seems that the garbage collection
takes very long time.

now let me explain my application arhitecture:

it has an login frame which starts first. here you can select one specific
application module which will be launched after login. a have an application
module which works fine. my problem is that in any module i need to have an
option to close that module and open the login frame. my module is also
based on a frame. my application hangs after 3-4 cycles of LOGIN -> CLOSE
MODULE -> LOGIN ................................

my  LOGIN frame initializes the MODULE frame with some code like:

frm.pack();
frm.validate();
frame_pos_size.frame_pos_size(frm,true);
this.dispose();

my MODULE frame closes itself and initializes LOGIN frame with some code
like:

ids_login frm = new ids_login();
frm.pack();
frm.validate();
frame_pos_size.frame_pos_size(frm,true);
this.dispose();

Please tell me what to try to solve this problem. Did i misunderstood the
concept of "disposing" a frame?

Thanks very much!

Adrian

Re: Swing Application Hangups (Garbage Collection?)

#1342

Author: Tad Frysinger [TeamB]
Date: Wed, 14 Jan 2004 19:36

72 lines
3785 bytes

Adrian -

dispose() causes all native resources (i.e. handles, graphics resources, 
etc.) to be released back to the underlying OS. I'm not sure what is 
causing your hangup, but I'll bet somehow you have a reference between 
those two frames, so they are each holding on to a hard reference to 
something causing a deadlock.

You can also structure your main app to switch between login and module 
frames in a number of ways. Here is one:

public class Examples {
   boolean packFrame = false;

   //Construct the application
   public Examples() {
     ModuleFrame module = null; // Interface, hopefully!
     LoginFrame l = new LoginFrame(); // login frame
     l.pack();
     //Center the window
     Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
     Dimension frameSize = l.getSize();
     if (frameSize.height > screenSize.height) {
       frameSize.height = screenSize.height;
     }
     if (frameSize.width > screenSize.width) {
       frameSize.width = screenSize.width;
     }
     l.setLocation( (screenSize.width - frameSize.width) / 2,
                        (screenSize.height - frameSize.height) / 2);
     boolean keepGoing = true;
     while ( keepGoing ) {
       l.setVisible(true);
       // Login is now visible. When it is closed, the user has indicated
       // somehow what action should be taken, including whether to end
       // the application, or open a new module. hide() is used, not
       // displose()
       switch ( l.getUserAction ) {
          case LoginFrame.CLOSE_APPLICATION :
             keepGoing = false;
             break;
          case LoginFrame.EXEC_MODULE :
             // Determine the module, credentials, etc. and instance the
             // appropriate ModuleFrame. This could be done generically
             // using Java reflection, or specifically if the modules
             // are unlikely to change.
             ModuleFrame frame = (ModuleFrame)<mechanism of choice>;
             frame.setVisible( true );
             // Determine if close means close the app or not, and
             // take appropriate action
             break;
          case LoginFrame.PASSWORD_EXCEPTION :
             // etc.
       }
   }

   //Main method
   public static void main(String[] args) {
     try {
       UIManager.setLookAndFeel(
        UIManager.getSystemLookAndFeelClassName());
     }
     catch(Exception e) {
       e.printStackTrace();
     }
     new Examples();
   }
}


-- 
Tad Frysinger [TeamB]

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