Browse Prior Art Database

Automatic State Update Chaining of Parts in a Reusable Programmed Component

IP.com Disclosure Number: IPCOM000116630D
Original Publication Date: 1995-Oct-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 79K

Publishing Venue

IBM

Related People

Farn, B: AUTHOR

Abstract

A computer programmer who wants a part, such as an entry field, to respond to state changes of another part, such as a list box, has to program in this behaviour into both parts. A method for building in a predefined behaviour into Reusable Programmed Component parts which eliminates this programming requirement is disclosed.

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

Automatic State Update Chaining of Parts in a Reusable Programmed
Component

      A computer programmer who wants a part, such as an entry field,
to respond to state changes of another part, such as a list box, has
to program in this behaviour into both parts.  A method for building
in a predefined behaviour into Reusable Programmed Component parts
which eliminates this programming requirement is disclosed.

      If a programmer wants to update the state of a part whenever
the state of a another part changes, the programmer must:
  o  Be notified when a part changes
  o  Read the state of the part that has changed
  o  Change the state of the second part based upon the new state of
      the first part.

This could be accomplished without any programming so that whenever
the source part's state changes, the target part's state changes
automatically.

      A chaining mechanism has been built into the Reusable
Programmed Component and component parts which allows for two or more
parts to be chained together such that:
  o  A source part is a part that is a provider of data
  o  A target part is a part that is a consumer of data
  o  All parts can be source parts
  o  All parts can be target parts
  o  Parts can be both source and target parts simultaneously
  o  Each source part has a list of target parts that are to be
      notified

      For example, a timer part is a part that can count.  It adds
one to its count after a predefined interval.  Two timers can be
chained together such that the source timer has an interval of 1
second, and the target timer has an interval of 0.1 seconds.  If both
timers are started together, then after one second, the target timer
will have reached a count of ten, and the source timer will have
reached a count of one.  Since the source timer has changed state, it
updates the target timer.  The target timer responds with its
predefined behaviour of resetting its count to zero.  Each timer can
be the source part for displayable text target parts.  Whenever the
state of each timer changes the corresponding displayed text is
updated.

      Parts can be chained together in a ring.  Whenever a target
part's new state is the same as its current state, its target parts
are not notified.  This prevents infin...