XML::Filter::Tee 0.41

XML::Filter::Tee can 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 and
## L 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 ],
);

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

Its 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 its 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.