use strict;
use warnings;
use 5.012;

use Exception::Class (
    'MyException',

    'CommandException' => { isa => 'MyException' },

    'TimeoutException' => {
        isa => 'CommandException',
        description =>
          'This exception resulted from running the metrics commands'
    },
    'DBException' => {
        isa         => 'MyException',
        description => 'DB returned error'
      }

);

&ThrowMyException();

sub ThrowMyException() {

    eval{ TimeoutException->throw(error=>"This is error due to timeout
+") };
    my $err;

    if ($err = Exception::Class->caught('TimeoutException') ) {
         #print Dumper($err);
         #print "err is of type ".ref($err);
         die $err->description . ": " . $err->error;
    }
    elsif ( $err = Exception::Class->caught("MetricsException") ) {
        #print Dumper($err);
        die $err->error;
    }


}
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If you see class names like A::B::C, that means the class is named C and it can be found in the directory A/B/. The A::B:: part is a namespace name to prevent name conflicts, but it also indicates the directory structure where the class is located. When you write A::B::C in your program, perl searches all the directories in @INC for a directory named A that has a subdirectory named B, which contains a file called C.pm.