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# $Id: ErrorHandler.pm,v 1.1.1.1 2004/08/15 14:55:43 btrott Exp $
package Class::ErrorHandler;
use strict;
use vars qw( $VERSION $ERROR );
$VERSION = '0.01';
sub error {
my $msg = $_[1] || '';
if (ref($_[0])) {
$_[0]->{_errstr} = $msg;
} else {
$ERROR = $msg;
}
return;
}
sub errstr {
ref($_[0]) ? $_[0]->{_errstr} : $ERROR
}
1;
__END__
=head1 NAME
Class::ErrorHandler - Base class for error handling
=head1 SYNOPSIS
package Foo;
use base qw( Class::ErrorHandler );
sub class_method {
my $class = shift;
...
return $class->error("Help!")
unless $continue;
}
sub object_method {
my $obj = shift;
...
return $obj->error("I am no more")
unless $continue;
}
package main;
use Foo;
Foo->class_method or die Foo->errstr;
my $foo = Foo->new;
$foo->object_method or die $foo->errstr;
=head1 DESCRIPTION
I<Class::ErrorHandler> provides an error-handling mechanism that's generic
enough to be used as the base class for a variety of OO classes. Subclasses
inherit its two error-handling methods, I<error> and I<errstr>, to
communicate error messages back to the calling program.
On failure (for whatever reason), a subclass should call I<error> and return
to the caller; I<error> itself sets the error message internally, then
returns C<undef>. This has the effect of the method that failed returning
C<undef> to the caller. The caller should check for errors by checking for a
return value of C<undef>, and calling I<errstr> to get the value of the
error message on an error.
As demonstrated in the L<SYNOPSIS>, I<error> and I<errstr> work as both class
methods and object methods.
=head1 USAGE
=head2 Class->error($message)
=head2 $object->error($message)
Sets the error message for either the class I<Class> or the object
I<$object> to the message I<$message>. Returns C<undef>.
=head2 Class->errstr
=head2 $object->errstr
Accesses the last error message set in the class I<Class> or the
object I<$object>, respectively, and returns that error message.
=head1 LICENSE
I<Class::ErrorHandler> is free software; you may redistribute it and/or modify
it under the same terms as Perl itself.
=head1 AUTHOR & COPYRIGHT
Except where otherwise noted, I<Class::ErrorHandler> is Copyright 2004
Benjamin Trott, cpan@stupidfool.org. All rights reserved.
=cut
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