[Zope] Extending Standard Objects

[Michel Pelletier]

> -----Original Message-----
> From: James W. Howe [mailto:jwh@allencreek.com]
> Sent: Tuesday, January 18, 2000 4:20 PM
> To: zope@zope.org
> Subject: [Zope] Extending Standard Objects
> 
> 
> In my experimentations with Zope, I'm trying to extend the 
> Image object to 
> include caption information and formatting.  I've created a 
> ZClass which 
> has Image as one of the base classes.  I'm a little confused 
> as to what to 
> do next.  For example, what properties do I need to defined.  
> Do I just 
> define the caption property?

Yep.

> Do I inherit any properties from Image 
> itself? 

You inherit all attributes of the base class, including properties and
methods.

> I also noticed that because I subclassed from Image, 
> certain views 
> are created for me by default.  The "Edit" view is defined to use 
> manage_main.  The "Upload" view uses manage_uploadForm.   

Yep.

> If 
> I want to 
> enhance the functionality of the Edit and Upload view, do I 
> just need to 
> create new methods on my ZClass and point the view at the new 
> method? 

Or you can override the existing methods.

> If I 
> wanted my views to look just like the normal views (manage_main and 
> manage_uploadForm) with only minor tweaking, where would I 
> find the source 
> to those methods?

They are on the filesystem, for Image object probably in lib/python/OFS.

I wouldn't change the documents on file, but rather copy them into new
methods of your new class and override the behavior you wish to 'tweak'.

-Michel