XML::SAX::Tap(3pm)					User Contributed Perl Documentation					XML::SAX::Tap(3pm)

NAME

       XML::SAX::Tap - Tap a pipeline of SAX processors

SYNOPSIS

	   use XML::SAX::Machines qw( Pipeline Tap ) ;

	   my $m = Pipeline(
	       "UpstreamFilter",
	       Tap( "My::Reformatter", *STDERR ),
	       "DownstreamFilter",
	   );

	   my $m = Pipeline(
	       "UpstreamFilter",
	       Tap( "| xmllint --format -" ),
	       "DownstreamFilter",
	   );

DESCRIPTION

       XML::SAX::Tap is a SAX machine that passes each event it receives on to a brach handler and then on down to it's main handler.  This allows
       debugging output, logging output, validators, and other processors (and machines, of course) to be placed in a pipeline.  This differs from
       XML::Filter::Tee, XML::Filter::SAXT and XML::SAX::Distributer in that a tap is also a pipeline; it contains the processoring that handles
       the tap.

       It's like XML::Filter::Tee in that the events are not buffered; each event is sent first to the tap, and then to the branch (this is
       different from XML::SAX::Dispatcher, which buffers the events).

       It's like XML::SAX::Pipeline in that it contains a series of processors in a pipeline; these comprise the "tapping" processors:

		   +----------------------------------------------+
		   |		      Tap instance		  |
		   |						  |
		   |  Intake					  |
		   |  +-----+	 +---------+	    +---------+   |
	upstream --+->| Tee |--->| Stage_0 |--...-->| Stage_N |   |
		   |  +-----+	 +---------+	    +---------+   |
		   |	     					  |
		   |	       			 Exhaust  |
		   |	       +----------------------------------+--> downstream
		   |						  |
		   +----------------------------------------------+

       The events are not copied, since they may be data structures that are difficult or impossibly to copy properly, like parts of a C-based DOM
       implementation.

       Events go to the tap first so that you can validate events using a tap that throws exceptions and they will be acted on before the tap's
       handler sees them.

       This machine has no "Exhaust" port (see XML::SAX::Machine for details about "Intake" and "Exhaust" ports).

METHODS

       new
	       my $tap = XML::SAX::Tap->new( @tap_processors, \%options );

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, as you choose.

perl v5.10.0							    2009-06-11							XML::SAX::Tap(3pm)