Browse Prior Art Database

Change the Class of an Existing Workplace Shell Object in OS/2

IP.com Disclosure Number: IPCOM000114593D
Original Publication Date: 1995-Jan-01
Included in the Prior Art Database: 2005-Mar-29
Document File: 2 page(s) / 65K

Publishing Venue

IBM

Related People

Campbell, D: AUTHOR

Abstract

Disclosed is a method for changing the class of an existing Workplace Shell* (WPS) object. The class of a single object can be changed without affecting other objects of the same class.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Change the Class of an Existing Workplace Shell Object in OS/2

      Disclosed is a method for changing the class of an existing
Workplace Shell* (WPS) object.  The class of a single object can be
changed without affecting other objects of the same class.

      The System Object Model (SOM) and the Workplace Shell make it
possible for a programmer to create new classes of objects in OS/2*
by extending existing classes.  The user can then create objects from
these new classes.  The user can also use a new class to replace its
parent class, thus adding function to all existing objects of the
parent class.

      For example, a programmer subclasses WPFolder to create a new
class, ExtendedFolder, with additional capabilities.  A user can then
create new ExtendedFolder objects, or the user can replace the
WPFolder class with the ExtendedFolder class, thereby changing all
existing Folders into ExtendedFolders.  It will also add the new
functions to all objects of classes that are descended from WPFolder.

      The user cannot add the ExtendedFolder functions to a single
existing Folder, while leaving all other Folders alone.  This
disclosure addresses that problem.

      In the current implementation, the WPS is a single process.
All WPS classes and objects run in this single process.  So, there is
no mechanism for protecting one object's address space from code
running for another object.  This makes the solution possible when
implemented as code running in the WPS process.

      A WPS object is represented in the computer's memory by a
structure.  One of the items within the structure points to a SOM
Method Table.  This Method Table identifies the class and functions
of the object....