NAME

Class::CompoundMethods - Create methods from components

SYNOPSIS

use Class::CompoundMethods 'append_method';

# This installs both versioning_hook and auditing_hook into the
# method Object::pre_insert.
for my $hook (qw(versioning auditing)) {
    append_method( 'Object::pre_insert', "${hook}_hook" );
}

sub versioning_hook { ... }
sub auditing_hook { ... }

DESCRIPTION

This allows you to install more than one method into a single method name. I created this so I could install both versioning and auditing hooks into another module's object space. So instead of creating a single larger method which incorporates the functionality of both hooks I created Class::CompoundMethods::append_method to install a wrapper method as needed.

If only one method is ever installed into a space, it is installed directly with no wrapper. If you install more than one then append_method creates a wrapper which calls each of the specified methods in turn.

PUBLIC METHODS

append_method

append_method( $method_name, $method );                

This function takes two parameters - the fully qualified name of the method to install into and the method to install.

$method_name must be the fully qualified method name. This means that for the method pre_insert of a Foo::Bar object you must pass in

'Foo::Bar::pre_insert'.

$method may be either a code reference or the fully qualified name of the method to use.

EXAMPLES

Example 1

use Class::CompoundMethods 'append_method';

# This installs both versioning_hook and auditing_hook into the
# method Object::pre_insert.
for my $hook (qw(versioning auditing)) {
    append_method( 'Object::pre_insert', "${hook}_hook" );
}

sub versioning_hook { ... }
sub auditing_hook { ... }

Example 2

use Class::CompoundMethods 'append_method';

my @versioned_tables = ( .... );
my @audited_tables = ( .... );


for my $table_list ( { tables => \ @versioned_tables,
                       prefix => 'versioned' },
                     { tables => \ @audited_tables,
                       prefix => 'audited' } ) {
    my $tables = $table_list->{'tables'};
    my $prefix = $table_list->{'prefix'};

    for my $table ( @$tables ) {
        for my $hook ( qw[pre_insert pre_update pre_delete]) {

            my $method_name = "GreenPartyDB::Database::${table}::${hook}";
            my $method_inst = __PACKAGE__ . "::${prefix}_${hook}";
            append_method( $method_name, $method_inst );

        }
    }
}

sub versioned_pre_insert { ... }
sub versioned_pre_update { ... }
sub versioned_pre_delete { ... }
sub audited_pre_insert { ... }
sub audited_pre_update { ... }
sub audited_pre_delete { ... }

EXPORT

This class optionally exports the append_method function.

COPYRIGHT & LICENSE

Copyright (c) 2003 Joshua b. Jore All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

AUTHOR

Joshua b. Jore <jjore@cpan.org>

SEE ALSO

RFC Class::AppendMethods http://www.perlmonks.org/index.pl?node_id=252199

Installing chained methods http://www.perlmonks.org/index.pl?node_id=251908