Here's how I like to do this:

I prefer keeping one bless in my module. I don't like having to check multiple places in the module for the blessing. I've had some headaches because of that.

I also like to think that most my modules 'use' or 'contain' a database handle. So my modules don't inherit from DBI. Instead, I opt for a the some sort of singleton factory to get a $dbh instance. There are plenty of ways to do this, here's one that I've been using.

HTH


package MyApp::Ticket;
use strict;

sub new 
{
    my ($class,%args) = @_;
    
    my $self = bless {};
    
    if ( $args{ticket_number} )
    {
        $self->load( $args{ticket_number} );
    }
    else
    {
        $self->init(%args);
    }
    
    return $self;
                
}

sub init
{
    my ($self,%args) = @_;    
    
    $$self{_time}                 => $args{'time'};
    $$self{_trade_ref}             => $args{'trade_ref'};
    $$self{_adr_buyer_bank}        => $args{'adr_buyer_bank'};
    $$self{_adr_seller_bank}    => $args{'adr_seller_bank'};
    $$self{_ti_seller_pays}        => $args{'seller_pays'};
    
    return $self;
}

sub load 
{
    my $self = shift;
    my $ticket_number = shift;
    
    #
    #    pull the $dbh from some shared location
    #    like a singleton factory
    #
    my $dbh = GetDBH();
    
    my $sql = "SELECT * FROM tickets WHERE id = ?";
    my $sth = $dbh->prepare($sql) or die $dbh->errstr;
    $sth->execute($ticket_number);
    my $row = $sth->fetchrow_hashref;
    return $self->init($$row);
}

#
#    and then initialize tickets like so: 
#

my $new_ticket = new MyApp::Ticket(
                          time=>time(),trad_ref=>34567,
                          adr_buyer_bank => 'blah',
                          adr_seller_bank =>'blah,
                          seller_pays => 99.99
                  );
                  
my $new_ticket = new MyApp::Ticket( ticket_number => 12345 );

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In reply to Re: how do i implement alternate constructors for an object by LanceDeeply
in thread how do i implement alternate constructors for an object by thunders

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