Class: HandlerCollection

• Inheritance
• Description
• Instance protocol
  • adding
  • private
  • save evaluation

Inheritance:

   Object
   |
   +--Collection
      |
      +--SequenceableCollection
         |
         +--OrderedCollection
            |
            +--HandlerCollection

Package:

stx:libbasic2

Category:

Kernel-Exceptions

Version:

rev: 1.5 date: 1999/07/28 21:00:09

user: cg

file: HandlerCollection.st directory: libbasic2

module: stx stc-classLibrary: libbasic2

Description:

A HandlerCollection allows a group of unrelated signals to be handled
by individual handlers - their evaluation is equivalent to a corresponding
number of nested signal handlers, but somwehat easier to program.
In the real world, handlerCollections are seldom needed and actually currently
not used by the system.

Instance protocol:

 on: aSignal handle: aHandler

add a signal<->handler pair to the receiver collection

 from: start to: stop handleDo: aBlock

this method recursively sets up a bunch of nested
handlers, and finally evaluates the argument, aBlock

 handleDo: aBlock

evaluate the argument, aBlock.
If any of the signals in the receiver is raised during evaluation,
evaluate the corresponding handleBlock from the receiver,
passing it an Exception argument.
The handler may decide how to react to the signal by sending
a corresponding message to the exception (see there).
If none of the signals is raised during evaluation, return the
value returned by aBlock.