Browse Prior Art Database

Overriding System Accelerators for Significant Performance Improvements

IP.com Disclosure Number: IPCOM000113164D
Original Publication Date: 1994-Jul-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 81K

Publishing Venue

IBM

Related People

Johnson, KD: AUTHOR [+2]

Abstract

Applications developed for the OS/2* Presentation Manager* (PM) are provided with an assortment of default system accelerators. Accelerators are keystroke combinations that provide a fast shortcut to requesting an action to occur. Two such accelerators provided by the system to all applications are the Select All (Ctrl-/) and the Deselect All (Ctrl-\) accelerators. These accelerators are used in selecting and deselecting all of the objects in a container.

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Overriding System Accelerators for Significant Performance Improvements

      Applications developed for the OS/2* Presentation Manager* (PM)
are provided with an assortment of default system accelerators.
Accelerators are keystroke combinations that provide a fast shortcut
to requesting an action to occur.  Two such accelerators provided by
the system to all applications are the Select All (Ctrl-/) and the
Deselect All (Ctrl-\) accelerators.  These accelerators are used in
selecting and deselecting all of the objects in a container.

      When one of these accelerators is pressed, PM sends a separate
message to the container control for each object being selected or
deselected.  These messages are the same that are received when the
user individually clicks on each object with the mouse.  The
container control has no way of knowing whether one or multiple items
are being selected, and therefore must perform all required
processing for a change in selection for each select or deselect that
it receives.

      This presents a performance problem when the processing is
extensive and there are many objects in the container.  An example is
with LAN NetView* View, which needs to update internal structures and
both popup and pulldown menus whenever a selection change occurs.

      It would result in much better performance if the container
were to receive only one message when one of these accelerators is
pressed, indicating that all objects in the container were being
selected or deselected.  This disclosure describes a technique that
can achieve this, resulting in greatly increased selection or
deselection performance.

      The solution to this performance problem is found in the
hierarchy of accelerator tables found in PM.  The system accelerator
table, containing the Select All and Deselect All accelerators, is
available to all applications.  The application can also define
private accelerators that only that application can access.  In the
PM accelerator hierarchy, the application accelerator table is
referenced before the system accelerator table.  If an accelerator is
found in the application accelerator table, a...