NAME Class::Trigger - Mixin to add / call inheritable triggers SYNOPSIS package Foo; use Class::Trigger; sub foo { my $self = shift; $self->call_trigger('before_foo'); $self->do_foo; $self->call_trigger('after_foo'); } package main; Foo->add_trigger(before_foo => \&sub1); Foo->add_trigger(after_foo => \&sub2); my $foo = Foo->new; $foo->foo; # then sub1, sub2 called # triggers are inheritable package Bar; use base qw(Foo); Bar->add_trigger(before_foo => \&sub); # triggers can be object based $foo->add_hook(after_foo => \&sub3); $foo->foo; # sub3 would appply only to this object DESCRIPTION Class::Trigger is a mixin class to add / call triggers (or hooks) that get called at some points you specify. METHODS By using this module, your class is capable of following two methods. add_trigger Foo->add_trigger($triggerpoint => $sub); $foo->add_trigger($triggerpoint => $sub); Adds triggers for trigger point. You can have any number of triggers for each point. Each coderef will be passed a copy of the object, and return values will be ignored. If "add_trigger" is called as object method, whole trigger table will be copied onto the object. Then the object should be implemented as hash. my $foo = Foo->new; # this trigger ($sub_foo) would apply only to $foo object $foo->add_trigger($triggerpoint => $sub_foo); $foo->foo; # And not to another $bar object my $bar = Foo->new; $bar->foo; call_trigger $foo->call_trigger($triggerpoint); Calls triggers for trigger point, which were added via "add_trigger" method. Each triggers will be passed a copy of the object. TRIGGER POINTS By default you can make any number of trigger points, but if you want to declare names of trigger points explicitly, you can do it via "import". package Foo; use Class::Trigger qw(foo bar baz); package main; Foo->add_trigger(foo => \&sub1); # okay Foo->add_trigger(hoge => \&sub2); # exception AUTHOR Original idea by Tony Bowden in Class::DBI. Code by Tatsuhiko Miyagawa . This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. SEE ALSO the Class::Data::Inheritable manpage