That's easy enough. Just make Obj a wrapper around a more specific instance, like the DBI module you mention. 
package main;    # example construction

my $obj = Obj->new('Database', @parameters);
my @data = $obj->get(@foo);

package Obj;

my %sources = {
    Database => Source::DB,
    XML => Source::XML,
    HTML => Source::HTML,
};

sub new {
    my $class = shift;
    my $source = shift;
    my $source_obj = init($sources{$source}, @_);
    my $self = {
        source => $source_obj,
    };
    bless($self, $class);
}

sub get {
    my $self = shift;
    return $self->{source}->get(@_);
}

[download]
Magic happens in the constructor :).

In reply to RE: RE: RE: Object Heirarchy / Design by chromatic
in thread Object Heirarchy / Design by lattice

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