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Bug 351585

Summary:	Make Dialogs usable from threadless life cycle
Product:	[RT] RAP	Reporter:	Rüdiger Herrmann <ruediger.herrmann>
Component:	RWT	Assignee:	Project Inbox <rap-inbox>
Status:	RESOLVED FIXED	QA Contact:
Severity:	enhancement
Priority:	P3
Version:	unspecified
Target Milestone:	1.5 M1
Hardware:	All
OS:	All
Whiteboard:
Bug Depends on:
Bug Blocks:	341761

Description Rüdiger Herrmann

2011-07-08 10:56:50 EDT

All subclasses of Dialog that come with RWT run a nested event loop in their open() method. This makes them unusable from applications that use the threadless life cycle (see bug 344091).
A callback should be introduced that notifies the application when the dialog was closed, like the sketch below shows:
  final FontDialog dialog = new FontDialog( parent, SWT.NONE );
  dialog.open( new DialogCallback() {
    public void dialogClosed() {
      applyFont( dialog.getFontList() );
    }
  } );

The challenge here is rather to find a way to provide the extra API that does not (or as least as possible) irritate users of the UI-threaded life cycle but is still as convenient as possible for users of the threadless lifefcyle.

Comment 1 Rüdiger Herrmann

2011-07-14 09:43:25 EDT

Dialog now implements Adaptable. Dialog#getAdapter() returns an IDialogAdapter that can be used to open dialogs in a non-blocking way.

In addition, I created preliminary API for application code to use this feature. org.eclipse.rwt.widgets.DialogUtil#open() can be used to open a given dialog without blocking and a DialogCallback can be supplied to be notified when the dialog was closed.

Alternatively the API could offer an abstract class _NonBlockingDialog_ (or similar) that combines the open() method from DialogUtil with the dialogClosed() callback method from DialogCallback.
abstract class NonBlockingDialog {
  NonBlockingDialog( Dialog dialog ) {
    // ...
  }
  
  void open() {
    // ...
  }
  
  abstract void dialogClosed( int returnCode )
}
application code:
NonBlockingDialog dialog = new NonBlockingDialog( fontDialog ) {
  void dialogClosed( int returnCode ) {
    // ...    
  }
}

What do you think?