hi monks,

i am trying to design an API to expose some commonly used methods from our internal modules. this api will be used in our webapps.

in the following example. i would like to provide a single access point and chain methods through the wrapper class. i.e $self->api->do_this and $self->api->do_that..

here is something i am uncertain about.. every web app will have a database handler and i would like to reuse it in the company::api. hence i am using it when initializing company::api and passing it down to every modules that need it. i feel clumsy about it.

being a design pattern newbie, i find it difficult to achieve a clean design. i would like to hear other monks opinion on this design..

btw, read some articles on design pattern and this example seems to match the object composition.. I better get my pattern design book real soon.. :) 

package company::api;
use company::logging;
use company::user;

sub new {
    my $class = shift;
    my $dbh = shift;
    my $uname = shift;

    my $self = {};
    $self->{__dbh} = $dbh;
    $self->{__log} = company::logging->new($self->{__dbh});
    $self->{__user} = company::user->new($self->{__dbh}, $uname );
    bless $self, $class;
} 

sub log_event { 
    my ($self, $log) = @_;
    $self->{__log}->log_event($log);
}

sub uid { 
    my $self = shift;
    unless ( $self->{__uid} ) {
        $self->{__uid} = $self->{__user}->get_uuid();
        }
    return $self->{__uid};
}
##### usage from webapp

package MyWebApp::Base;

sub api {
    unless ($self->{__api})  {
        $self->{__api} = company::api->new( MyWebApp::DB->dbh, $ENV{RE
+MOTE_USER} );
    }
    return $self->{__api};    
}

package MyWebApp::ControllerOne
use base 'MyApp::Base';

sub testing {
    my $uid = $self->api->uid;
    $self->api->log_event("$uid is testing");
}

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In reply to question on OO design and object composition by Qiang

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