Re: [albireo-dev] Re: populate

[Gordon Hirsch <gordon.hirsch@xxxxxxx>]

You're very fast :-) I was thinking of something a little different. 
Could we automatically call populate() from setBounds() (or some event 
handler)? That would remove the pitfall altogether. It might be tricky.

Bruno Haible wrote:
> What can we do avoid this pitfall?
>
> I was tempted to propose to change the SwingControl constructor to call
> populate().
>
> But then we have a constructor which indirectly calls an overridden method.
> And this causes trouble, because when this overridden method is invoked,
> the fields of that subclass are still not initialized, and initialization
> code   { ... }   has not been executed.
>
> So, I'm applying this pitfall catcher.
>
> Bruno
>
>
> Index: src/org/eclipse/albireo/core/SwingControl.java
> ===================================================================
> RCS file: /cvsroot/technology/org.eclipse.albireo/org.eclipse.albireo.core/src/org/eclipse/albireo/core/SwingControl.java,v
> retrieving revision 1.5
> diff -c -3 -r1.5 SwingControl.java
> *** src/org/eclipse/albireo/core/SwingControl.java      25 Jan 2008 21:24:50 -0000      1.5
> --- src/org/eclipse/albireo/core/SwingControl.java      25 Jan 2008 21:51:46 -0000
> ***************
> *** 22,27 ****
> --- 22,28 ----
>   import org.eclipse.swt.SWT;
>   import org.eclipse.swt.SWTException;
>   import org.eclipse.swt.awt.SWT_AWT;
> + import org.eclipse.swt.graphics.Rectangle;
>   import org.eclipse.swt.layout.FillLayout;
>   import org.eclipse.swt.widgets.Composite;
>   import org.eclipse.swt.widgets.Display;
> ***************
> *** 214,219 ****
> --- 215,234 ----
>       protected void afterComponentCreatedSWTThread() {
>       }
>
> +     private boolean populatedChecked = false;
> +     /**
> +      * Checks that <code>populate()</code> has already been called.
> +      * This is a convenience for the programmers.
> +      */
> +     private void checkPopulated() {
> +         if (!populatedChecked) {
> +             populatedChecked = true;
> +             if (!populated) {
> +                 System.err.println("org.eclipse.albireo.SwingControl instance "+this+" is still empty - did you forget to call populate()?");
> +             }
> +         }
> +     }
> +
>       // ========================================================================
>       // Accessors
>
> ***************
> *** 237,240 ****
> --- 252,275 ----
>       }
>
>       // ========================================================================
> +     // Size management
> +
> +     // This is called by the layout when it assigns a size and position to this
> +     // Control.
> +     /**
> +      * Overridden.
> +      */
> +     public void setBounds(Rectangle rect) {
> +         checkPopulated();
> +         super.setBounds(rect);
> +     }
> +     /**
> +      * Overridden.
> +      */
> +     public void setBounds(int x, int y, int width, int height) {
> +         checkPopulated();
> +         super.setBounds(x, y, width, height);
> +     }
> +
> +     // ========================================================================
>   }
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