use strict;
use warnings;

use Data::Dumper;
use XML::Twig;

my $twig = XML::Twig->new(
  start_tag_handlers => { 'UML:Class' => \&ulm_class, }, 
  twig_handlers      => { 'UML:Class' =>  sub { $_[0]->purge }, # purge at the end of each section,
                          'UML:Attribute' => \&uml_attr,
 } );
$twig->parsefile( 'testfile.xmi' );


sub uml_class
{
    my ( $twig, $section ) = @_;

    print "data for class:\n";
    print "   name = ", $section->att( 'name' ), "\n";
    print "   xmi.id = ", $section->att( 'xmi.id' ), "\n";
}


sub uml_attr
{
    my ( $twig, $attr ) = @_;
    # if you need the class id, it's in $attr->parent( ''UML:Class')->attr( 'xmi.id')
    $attr->print;

    print Dumper( $struct );
    # parse the block and extract the data elements

    $twig->purge;
}