Programming the Perl DBI

Object accessor methods

A final gloss on the Megalith class would be to add accessor methods to allow controlled access to the values stored within each object. That is, the example code listed above contains code that explicitly accesses member variables within the object:

print "Megalith Name: $megalith->{name}\n";

This may cause problems if the internal structure of the Megalith object alters in some way. Also, if you write $megalith->{nme} by mistake, no errors or warnings will be generated. Defining an accessor method called getName( ), such as:

### Returns the name of the megalith
sub getName {
    my ( $self ) = @_;
    return $self->{name};
}

makes the code arguably more readable:

print "Megalith Name: " . $megalith->getName(  ) . "\n";

and also ensures the correctness of the application code, since the actual logic is migrated, once again, into the object.