Description Dejan Glozic 2001-10-10 22:21:41 EDT

There is a need for dynamic property descriptors. Right now, property descriptor is asked to provide a cell editor.
This editor is cached and reused (method 'getCellEditor' is called only once). This is appropriate for static cases.
However, some properties may change nature depending on other properties' values. Example:

PDE XML Schema editor exposes attribute properties through the property sheet. Attribute 'type' is a set of
choices (string, boolean, etc.). There can also be a restriction on a base type (for example, base type 'string'
can be restricted with a list of choices - an enumeration). Depending on values of properties 'type' and 
'restriction', property 'value' needs to use different cell editors. For a 'boolean' type, default value
can only be 'true' or 'false'. For a 'string' type, it should be a text cell editor. However, if there
is an enumeration restriction on the 'string' type, 'value' cell editor should be a combo box containing only
the list of choices defined on the restriction.

Right now, I am using text cell editor and trying to catch restriction violation using cell validator.
However, this is against the good UI design practice to dissalow users to enter invalid input in the
first place, rather than punish them later.

This would be easy to implement if 'getCellEditor' on the property descriptor would be called each time.
The implementation of the desciptor can choose to cache the editor, or create a new widget every time.
The key is to provide an API on IPropertyDescriptor interface to indicate that cell editor should
not be cached by the property sheet entry (IPropertyDescriptor.setDynamic(boolean)/isDynamic() seem
like a sensible choice). If the returned value is true, cell editor would not be cached. The default
return value would be 'false', indicating behaviour as today.


NOTES: