NAME
    Pipeline - Generic pipeline interface

SYNOPSIS
      use Pipeline;
      my $pipeline = Pipeline->new();
      $pipeline->add_segment( @segments );
      $pipeline->dispatch();

DESCRIPTION
    "Pipelines" are a mechanism to process data. They are designed to be
    plugged together to make fairly complex operations act in a fairly
    straightforward manner, cleanly, and simply.

USING THE PIPELINE MODULE
    The usage of the generic pipeline module is fairly simple. You
    instantiate a Pipeline object by using the *new()* constructor.

    Segments can be added to the pipeline with the add_segment method.

    The store that the Pipeline will use can be set by calling the *store()*
    method later on. If a store is not set by the time a pipeline is
    executing then it will use a store of the type "Pipeline::Store::Simple"

    To start the pipeline running call the *dispatch()* method on your
    Pipeline object.

    To see what is being dispatched within a pipeline dispatch set the
    pipeline's debug value to true.

WRITING A PIPELINE
  INHERITANCE
    Pipelines are designed to be inherited from. The inheritance tree is
    somewhat warped and should look a little like this:

         MySegment --> Pipeline::Segment <--- Pipeline

    In other words, everything is a pipeline segment.

  METHODS
    init()
        Things to do at construction time. If you do override this, its will
        often be fairly important that you call $self->SUPER::init() to make
        sure that the setup is done correctly.

    add_segment( LIST )
        Adds a segment or segments to the pipeline.

    add_cleanup( LIST )
        Adds a segment or segments to the cleanup pipeline, that gets
        executed after the pipeline has finished.

    dispatch()
        Starts the pipeline execution, returns the production or undef

    dispatch_loop( Pipeline, [ ARRAYREF ] )
        The "dispatch_loop" method performs the processing for the pipeline

    dispatch_segment( Pipeline::Segment )
        The "dispatch_segment" method handles the execution of an individual
        segment object.

    cleanup( [ value ] )
        "cleanup" gets and sets the value of the cleanup list. At
        initialization this is set to an array reference.

    pipeline( [ value ] )
        "pipeline" gets and sets the value of the pipeline list. At
        initialization this is set to an array reference.

    store( [ Pipeline::Store ] )
        "store" gets and sets the value of a Pipeline's store. At
        initialization this is set to a Pipeline::Store::Simple object.

SEE ALSO
    "Pipeline::Segment"

AUTHOR
    James A. Duncan <jduncan@fotango.com> Leon Brocard <acme@astray.com>

COPYRIGHT
    Copyright 2002 Fotango Ltd. Licensed under the same terms as Perl
    itself.