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Subclassing Text [message #778951]

Sat, 14 January 2012 07:52

Timothy Vogel

Messages: 76
Registered: July 2009

Member

I need to provide default behavior on all text fields in an application. Examples are selectAll() on gainFocus and restriction to a subset of keys.

My first approach was to build a class hierarchy anchored on Text but it is marked @noextend. The only other way I can come up with is to add the code to each control individually or in a loop. This appears to me to be very non-OO and difficult to support.

Can anyone educate me on the reason that Text is marked @noextend? A link to existing discussion would be great.

Thanks for taking the time to read my question!
Timothy Vogel

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Re: Subclassing Text [message #779798 is a reply to message #778951]

Mon, 16 January 2012 15:22

Grant Gayed

Messages: 2151
Registered: July 2009

Senior Member

See http://www.eclipse.org/swt/faq.php#subclassing . The suggested
approach is to create a class of your own that wraps Text (not
subclasses it), and create instances of your class instead of Text.

Grant

On 1/14/2012 2:52 AM, Timothy Vogel wrote:
> I need to provide default behavior on all text fields in an application.
> Examples are selectAll() on gainFocus and restriction to a subset of keys.
>
> My first approach was to build a class hierarchy anchored on Text but it
> is marked @noextend. The only other way I can come up with is to add the
> code to each control individually or in a loop. This appears to me to be
> very non-OO and difficult to support.
>
> Can anyone educate me on the reason that Text is marked @noextend? A
> link to existing discussion would be great.
>
> Thanks for taking the time to read my question!
> Timothy Vogel

Report message to a moderator