[4071] in java-interest
Re: [Q] getWidth(this), why passing 'this'?
daemon@ATHENA.MIT.EDU (Pradeep Badri)
Fri Dec 8 23:25:33 1995
From: Pradeep Badri <pbadri@cisco.com>
To: edith@pencom.com (Edith Au)
Date: Fri, 8 Dec 95 18:02:57 PST
Cc: java-interest@java.sun.com
In-Reply-To: <9512081655.aa29746@china.pencom.com>; from "Edith Au" at Dec 8, 95 4:55 pm
Hi,
One of the elements in Applet inheritance hierarchy is the
Component class which implements ImageObserver and provides
a default implementation. That's the reason why you could pass "this"
to getWidth() function. You could override it if you want
your implementation.
cheers,
-pb.
Pradeep Badri.
Cisco Systems.
>
> Hi,
>
> public class a extends Applet
> {
> Image im;
>
> public void init()
> {
> try
> {
> im = getImage(/* an image */);
> }
> catch (Exception e)
> {}
>
> imWidth = im.getWidth(this);
> }
> }
>
> According to the API, getWidth takes an ImageObserver object as a parameter.
> 'this' is an applet. The only common ancestor of Applet and imageObserver is
> Object. How come 'this' can be passed as an mageObserver?
>
> -Edith
> -
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