NAME

XML::Filter::Tee - Send SAX events to multiple processor, with switching

SYNOPSIS

my $t = XML::Filter::Tee->new(
    { Handler => $h0 },
    { Handler => $h1 },
    { Handler => $h2 },
    ...
);

## Altering the handlers list:
$t->set_handlers( $h0, $h1, $h2, $h3 );

## Controlling flow to a handler by number and by reference:
$t->disable_handler( 0 );
$t->enable_handler( 0 );

$t->disable_handler( $h0 );
$t->enable_handler( $h0 );

## Use in a SAX machine (though see L<XML::SAX::Pipeline> and
## L<XML::SAX::Tap> for a more convenient way to build a machine
## like this):
my $m = Machine(
    [ Intake => "XML::Filter::Tee" => qw( A B ) ],
    [ A      => ">>log.xml" ],
    [ B      => \*OUTPUT ],
);

DESCRIPTION

XML::Filter::Tee is a SAX filter that passes each event it receives on to a list of downstream handlers.

It's like XML::Filter::SAXT 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). Unlike XML::Filter::SAXT, it allows it's list of handlers to be reconfigured (via "set_handlers") and it allows control over which handlers are allowed to receive events. These features are designed to make XML::Filter::Tee instances more useful with SAX machines, but they to add some overhead relative to XML::Filter::SAXT.

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. This means that the handlers must not alter the events or later handlers will see the alterations.

METHODS

new

my $t = XML::Filter::Tee->new(
    { Handler => $h0 },
    { Handler => $h1 },
    { Handler => $h2 },
    ...
);

set_handlers

$t->set_handlers( $h0, $h1, $h2 );
$t->set_handlers( {
        Handler => $h0,
    },
    {
        Handler => $h1,
    },
);

Replaces the current list of handlers with new ones.

Can also name handlers to make enabling/disabling them by name easier:

$m->set_handlers( {
        Handler => $validator,
        Name    => "Validator",
    },
    {
        Handler => $outputer,
    },
);

$m->disable_handler( "Validator" );

disable_handler

$t->disable_handler( 0 );            ## By location
$t->disable_handler( "Validator" );  ## By name
$t->disable_handler( $h0 );          ## By reference

Stops sending events to the indicated handler.

enable_handler

$t->enable_handler( 0 );            ## By location
$t->enable_handler( "Validator" );  ## By name
$t->enable_handler( $h0 );          ## By reference

Stops sending events to the indicated handler.

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.