use warnings;
use strict;
use XML::Twig;

my $xml = <<XML;
<ROOT hostname="bumblebee" tstamp="2011/09/21 22:24:05">
        <APPLICATION>
                <PORT>7777</PORT>
                <APP_HOME>/extra/localcw/opt/APP/sun4</APP_HOME>
                <VERSION>V36.11.01</VERSION>
                <PERF_HOME>/usr/localcw/opt/APP/Solaris-2-9-sparc-64</PERF_HOME>
                <PERF_VERSION>glanceSunOS 5.9 (Solaris 9) (sparc, 64 Bit) 7.3.00.6059 Jul 19 2006</PERF_VERSION>
                <STAR_VERSION>3.0</STAR_VERSION>
                <DEFAULT_ACCT>root</DEFAULT_ACCT>
                <HISTORY_RETENTION>90</HISTORY_RETENTION>
                <LAST_FILE_DOWN>StAR-201105090928.tar</LAST_FILE_DOWN>
                <LAST_STATUS>No download file found</LAST_STATUS>
                <ACL>
                        <ACCOUNT id="f9a64ef61c">
                                <MD5>f9a64ef61c</MD5>
                                <USERNAME>*</USERNAME>
                                <HOST>flower</HOST>
                                <PERMISSION>P</PERMISSION>
                        </ACCOUNT>
                </ACL>
        </APPLICATION>
</ROOT>
XML

my $twig = XML::Twig->new(
    twig_roots => {'APPLICATION' => \&doStuff, 'ACL' => \&doStuff}
);

$twig->parse($xml);


sub doStuff {
    my ($t, $elt) = @_;

    print "Found ", $elt->tag(), "\n";
    $t->purge;    # frees the memory
}