Pipeline::Segment::AsyUser)Contributed Perl DocumenPipeline::Segment::Async(3)NAMEPipeline::Segment::Async - asynchronous pipeline segments
SYNOPSIS
my $seg = $pipe->store->get( $async_segment_classname );
my $ret = $seg->reattach();
DESCRIPTION
The "Pipeline::Segment::Async" module allows you to write asynchronous
pipeline segments. Whenever an asynchronous segment is dispatched it
places itself in the store, and splits away from the main process that
keeps running. At any point furthe down the pipeline you can request
the segment from the store, and then ask it to give you back its return
values by calling the "reattach()" method, or even, throw them away by
calling "discard()" which will simply destroy the segment when it
completes. If you call "discard()" there is no way you can get it
back.
You add any asynchronous segment to the a pipeline in exactly the same
manner you would add any other segment. It gets dispatched in the
normal way, with the normal arguments supplied to the dispatch method.
Getting objects from the store will retrieve them as expected. however
altering those objects or setting them back into the store will not do
what you expect.
"Pipeline::Segment::Async" works by indicating to the dispatcher that
it wants a different method to be its dispatch method. If you indicate
to the dispatcher that you want something to dispatch different at the
segment level, then your asynchronous segment will be come decidedly
synchronous.
"Pipeline::Segment::Async" inherits from "Pipeline::Base" and has any
methods that it provides.
METHODSinit()
"init()" is called by the constructor, and sets up the list of
threading models that "Pipeline::Segment::Async" is aware of. See
"threading_models()" for more information.
threading_models( [ARRAYREF] )
"threading_models()" gets and sets a list of classes that know how
to process segements asynchronously.
predispatch()
"predispatch()" is called by the pipeline dispatcher and prepares
the segment for asynchronous execution.
model( [Pipeline::Segment::Async::*] )
"model()" returns an object that represents the threading model
that "Pipeline::Segment::Async" will call. If it does not yet have
an object a call to "determine_threading_model()" is called.
determine_threading_model()
"determine_threading_model()" will look at all the classes in the
list provided by "threading_models()" and determine if they can
operate under the current configuration. It will return an object
of one of those classes, provided it can operate.
reattach()
"reattach()" takes a detached asynchronous segment and joins it
back, placing the results in the correct area of the pipeline.
discard()
"discard()" flags an asynchronous segment as never needing to be
reattached.
dispatch_method()
"dispatch_method()" tells the pipeline dispatch class which method
to call in order to dispatch this class. In the case of
"Pipeline::Segment::Async" it returns a constant with the value
predispatch.
SEE ALSO
Pipeline::Segment, Pipeline::Dispatch, Pipeline::Base,
Pipeline::Segment::Async::Handler
AUTHOR
James A. Duncan <jduncan@fotango.com>
COPYRIGHT
Copyright 2003 Fotango Ltd. All Rights Reserved.
This software is released under the same terms as Perl itself.
perl v5.14.1 2004-08-09 Pipeline::Segment::Async(3)
