in reply to need some OO help

Just put an empty ("abstract") method in your base class, which your subclasses will use to get the path.

package BaseConf;

my $Conf;

sub _load_config {
    my $self = shift;
    my $conf_file = $self->config_file_path;
    croak "unable to find $conf_file" 
      unless -e $conf_file and -r $conf_file;

    $Conf = Config::Tiny->read( $conf_file );
  croak "read config file '$conf_file' failed: $Config::Tiny::errstr" 
      unless $Conf;
}


sub config_file_path { 
    croak "config_file_path must be provided by subclass.";
}

...

package MyConf;

use base 'BaseConf';

sub config_file_path { 
    return '/path/to/conf.file';
}

[download]

Replies are listed 'Best First'.
Re^2: need some OO help
by Qiang (Friar) on Mar 26, 2007 at 19:59 UTC
    thanks. that should fix it except..

    since i am using BEGIN { _load_config() } in base class. how do i get around using the method you suggested?

[reply]
[d/l]

      Put it in your derived class instead (and turn it into a class method.)

      package MyConf;

...

BEGIN { 
    __PACKAGE__->_load_config;
}

      [download]

      That will call _load_config (as a method) in your parent class, which will call config_file_path in your child class.

[reply]
[d/l]
[select]
        i see. in that case, i could just have the following line in my subclass: 
        BEGIN { __PACKAGE__->load_config('path/to/my.conf') }

        [download]
        i prefer to not knowing that kind of detail in the parent class. another way that may look cleaner is 
        package BaseConf;

sub config_file_path { croak "must implemeted in subclass" }

sub load_config {
    my $self = shift;
    my $conf_file = $self->config_file_path;
    croak "unable to find $conf_file" unless -e $conf_file and -r $con
+f_file;

    my $cfg = Config::Tiny->read( $conf_file );
    croak "read config file '$conf_file' failed: $Config::Tiny::errstr
+" unless $cfg;
    return $cfg;
}

ub get {
    my $self = shift;
    my $cfg  = $self->load_config;
    croak "invalid method called $_[0]" if not exists $cfg->{_}->{ $_[
+0] };
    return $cfg->{_}->{ $_[0] };
}
sub import { ... } 
sub AUTOLOAD { .. } 

package MyConf;
use base 'BaseConf';

sub config_file_path { return "path/to/my.conf" }

        [download]
        in plain CGI, Config::Tiny object is created for every config directive in sub import {}. maybe bad for performance. i am not sure if the same C::T object gets shared under mod_perl env.
[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom