NAME

       XML::SAX::Pipeline - Manage a linear pipeline of SAX processors

VERSION

       version 0.46

SYNOPSIS

           use XML::SAX::Machines qw( Pipeline );   ## Most common way
           use XML::Fitler::Foo;

           my $m = Pipeline(
               XML::Filter::Foo->new,  ## Create it manually
               "XML::Filter::Bar",     ## Or let Pipeline load & create it
               "XML::Filter::Baz",
               {
                   ## Normal options
                   Handler => $h,
               }
           );

           ## To choose the default parser automatically if XML::Filter::Foo
           ## does not implement a parse_file method, just pretend the Pipeline
           ## is a parser:
           $m->parse_file( "blah" );

           ## To feed the pipeline from an upstream processor, treat it like
           ## any other SAX filter:
           my $p = Some::SAX::Generator->new( Handler => $m );

           ## To read a file or the output from a subprocess:
           my $m = Pipeline( "<infile.txt" );
           my $m = Pipeline( "spew_xml |" );

           ## To send output to a file handle, file, or process:
           my $m = Pipeline( ...,  \*STDOUT );
           my $m = Pipeline( ..., ">outfile.txt" );
           my $m = Pipeline( ..., "| xmllint --format -" );

DESCRIPTION

       An XML::SAX::Pipeline is a linear sequence SAX processors.  Events passed to the pipeline
       are received by the "Intake" end of the pipeline and the last filter to process events in
       the pipeline passes the events out the "Exhaust" to the filter set as the pipeline's
       handler:

          +-----------------------------------------------------------+
          |                 An XML:SAX::Pipeline                      |
          |    Intake                                                 |
          |   +---------+    +---------+         +---------+  Exhaust |
        --+-->| Stage_0 |--->| Stage_1 |-->...-->| Stage_N |----------+----->
          |   +---------+    +---------+         +---------+          |
          +-----------------------------------------------------------+

       As with all SAX machines, a pipeline can also create an ad hoc parser (using
       XML::SAX::ParserFactory) if you ask it to parse something and the first SAX processer in
       the pipeline can't handle a parse request:

          +-------------------------------------------------------+
          |                 An XML:SAX::Pipeline                  |
          |                 Intake                                |
          | +--------+   +---------+         +---------+  Exhaust |
          | | Parser |-->| Stage_0 |-->...-->| Stage_N |----------+----->
          | +--------+   +---------+         +---------+          |
          +-------------------------------------------------------+

       or if you specify an input file like so:

          my $m = Pipeline(qw(
              <input_file.xml
              XML::Filter::Bar
              XML::Filter::Baz
          ));

       Pipelines (and machines) can also create ad hoc XML::SAX::Writer instances when you
       specify an output file handle (as shown in the SYNOPSIS) or an output file:

          my $m = Pipeline(qw(
              XML::Filter::Bar
              XML::Filter::Baz
              >output_file.xml
          ));

       And, thanks to Perl's magic open (see perlopentut), you can read and write from processes:

          my $m = Pipeline(
              "gen_xml.pl |",
              "XML::Filter::Bar",
              "XML::Filter::Baz",
              "| consume_xml.pl",
          );

       This can be used with an XML::SAX::Tap to place a handy debugging tap in a pipeline (or
       other machine):

          my $m = Pipeline(
              "<input_file.xml"
              "XML::Filter::Bar",
              Tap( "| xmllint --format -" ),
              "XML::Filter::Baz",
              ">output_file.xml",
          );

NAME

       XML::SAX::Pipeline - Manage a linear pipeline of SAX processors

METHODS

       See XML::SAX::Machine for most of the methods.

       new
               my $pipeline = XML::SAX::Pipeline->new( @processors, \%options );

           Creates a pipeline and links all of the given processors together.  Longhand for
           Pipeline().

AUTHOR

           Barrie Slaymaker <barries@slaysys.com>

COPYRIGHT

           Copyright 2002, Barrie Slaymaker, All Rights Reserved.

       You may use this module under the terms of the Artistic, GNU Public, or BSD licenses, your
       choice.

AUTHORS

       •   Barry Slaymaker

       •   Chris Prather <chris@prather.org>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2013 by Barry Slaymaker.

       This is free software; you can redistribute it and/or modify it under the same terms as
       the Perl 5 programming language system itself.