aspose file tools*
The moose likes Swing / AWT / SWT and the fly likes Where to read/write properties in Swing application? Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login


Win a copy of Spring in Action this week in the Spring forum!
JavaRanch » Java Forums » Java » Swing / AWT / SWT
Bookmark "Where to read/write properties in Swing application?" Watch "Where to read/write properties in Swing application?" New topic
Author

Where to read/write properties in Swing application?

Klaas van Gelder
Ranch Hand

Joined: Jul 08, 2004
Posts: 100
Hell, it is about 5 years ago I posted on this forum and haven't done any Java programming since 2 years.... But I have a new project again, and a very trivial problem.

I work on a program with a Swing GUI, and according to the guidelines, I start the GUI in the event dispatch thread. My main class is not GUI aware, I consider it as good practice to have aa non-Swing aware main class but maybe this idea is a bit obsolete...


Not very special, the issue is that the constructor of the main class returns immediately and the main object gets out of scope. Even the main() methods returns immediately so the main thread ends.

So there is not really a good place to place code to save the property file when the aplication is closed. Is the finalize() method maybe a good location? I do not think so, nor do I think the reading and writing of the property file belongs in the GUI classes.... In each case the reading and writing of the property file shoud occur in the same class I guess.
Obviously this is a trivial problem and solved more than a thousand times What do I miss here?
REgards, Klaas


"What you don't know, can't help you"
SCJP (81%), SCWCD (81%), SCJD (354/400), SCBCD (85%)
Rob Spoor
Sheriff

Joined: Oct 27, 2005
Posts: 19719
    
  20

Runtime.getRuntime.addShutdownHook(...)

This will always be called when the JVM shuts down except when:
  • you call Runtime.getRuntime().halt(...)
  • the JVM is forcefully terminated (using sigkill in Linux or from the processes tab of Windows' Task Manager). Terminating through sigclose (Linux) or from the applications tab of Windows' Task Manager does call them, as far as I know.
  • although I'm not 100% sure, I also believe shutdown hooks are not called when the JVM is terminated because Windows / Linux shuts down completely.


  • SCJP 1.4 - SCJP 6 - SCWCD 5 - OCEEJBD 6
    How To Ask Questions How To Answer Questions
    Klaas van Gelder
    Ranch Hand

    Joined: Jul 08, 2004
    Posts: 100
    Thanks, this works indeed! Never seen that before.... I wonder if this is indeed the way most programs handle the writing of persistent data in standalone applications.
     
    Consider Paul's rocket mass heater.
     
    subject: Where to read/write properties in Swing application?