1Pipeline::Segment::AsynUcs(e3r)Contributed Perl DocumentPaitpieolnine::Segment::Async(3)
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NAME

6       Pipeline::Segment::Async - asynchronous pipeline segments
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SYNOPSIS

9         my $seg = $pipe->store->get( $async_segment_classname );
10         my $ret = $seg->reattach();
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DESCRIPTION

13       The "Pipeline::Segment::Async" module allows you to write asynchronous
14       pipeline segments.  Whenever an asynchronous segment is dispatched it
15       places itself in the store, and splits away from the main process that
16       keeps running. At any point furthe down the pipeline you can request
17       the segment from the store, and then ask it to give you back its return
18       values by calling the "reattach()" method, or even, throw them away by
19       calling "discard()" which will simply destroy the segment when it
20       completes.  If you call "discard()" there is no way you can get it
21       back.
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23       You add any asynchronous segment to the a pipeline in exactly the same
24       manner you would add any other segment.  It gets dispatched in the
25       normal way, with the normal arguments supplied to the dispatch method.
26       Getting objects from the store will retrieve them as expected. however
27       altering those objects or setting them back into the store will not do
28       what you expect.
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30       "Pipeline::Segment::Async" works by indicating to the dispatcher that
31       it wants a different method to be its dispatch method. If you indicate
32       to the dispatcher that you want something to dispatch different at the
33       segment level, then your asynchronous segment will be come decidedly
34       synchronous.
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36       "Pipeline::Segment::Async" inherits from "Pipeline::Base" and has any
37       methods that it provides.
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METHODS

40       init()
41           "init()" is called by the constructor, and sets up the list of
42           threading models that "Pipeline::Segment::Async" is aware of.  See
43           "threading_models()" for more information.
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45       threading_models( [ARRAYREF] )
46           "threading_models()" gets and sets a list of classes that know how
47           to process segements asynchronously.
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49       predispatch()
50           "predispatch()" is called by the pipeline dispatcher and prepares
51           the segment for asynchronous execution.
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53       model( [Pipeline::Segment::Async::*] )
54           "model()" returns an object that represents the threading model
55           that "Pipeline::Segment::Async" will call. If it does not yet have
56           an object a call to "determine_threading_model()" is called.
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58       determine_threading_model()
59           "determine_threading_model()" will look at all the classes in the
60           list provided by "threading_models()" and determine if they can
61           operate under the current configuration.  It will return an object
62           of one of those classes, provided it can operate.
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64       reattach()
65           "reattach()" takes a detached asynchronous segment and joins it
66           back, placing the results in the correct area of the pipeline.
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68       discard()
69           "discard()" flags an asynchronous segment as never needing to be
70           reattached.
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72       dispatch_method()
73           "dispatch_method()" tells the pipeline dispatch class which method
74           to call in order to dispatch this class.  In the case of
75           "Pipeline::Segment::Async" it returns a constant with the value
76           predispatch.
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SEE ALSO

79       Pipeline::Segment, Pipeline::Dispatch, Pipeline::Base,
80       Pipeline::Segment::Async::Handler
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AUTHOR

83       James A. Duncan <jduncan@fotango.com>
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86       Copyright 2003 Fotango Ltd. All Rights Reserved.
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88       This software is released under the same terms as Perl itself.
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92perl v5.12.0                      2004-08-09       Pipeline::Segment::Async(3)
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