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 com‐
20       pletes.  If you call "discard()" there is no way you can get it back.
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22       You add any asynchronous segment to the a pipeline in exactly the same
23       manner you would add any other segment.  It gets dispatched in the nor‐
24       mal way, with the normal arguments supplied to the dispatch method.
25       Getting objects from the store will retrieve them as expected. however
26       altering those objects or setting them back into the store will not do
27       what you expect.
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29       "Pipeline::Segment::Async" works by indicating to the dispatcher that
30       it wants a different method to be its dispatch method. If you indicate
31       to the dispatcher that you want something to dispatch different at the
32       segment level, then your asynchronous segment will be come decidedly
33       synchronous.
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35       "Pipeline::Segment::Async" inherits from "Pipeline::Base" and has any
36       methods that it provides.
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METHODS

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

78       Pipeline::Segment, Pipeline::Dispatch, Pipeline::Base, Pipeline::Seg‐
79       ment::Async::Handler
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AUTHOR

82       James A. Duncan <jduncan@fotango.com>
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85       Copyright 2003 Fotango Ltd. All Rights Reserved.
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87       This software is released under the same terms as Perl itself.
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91perl v5.8.8                       2004-08-09       Pipeline::Segment::Async(3)
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