Module Design and Implementation

clear_model(), and so on. This extra method is unnecessary, since you can always call 

$obj >id(undef) to clear the value of an attribute. Fortunately, Class::MethodMaker is 

highly configurable. Here's a few variations on the default get_set:

package BOA::Probe;

use Class::MethodMaker

   new     =>  new ,

   get_set =>  id ,                    # creates id() and clear_id()

   get_set => [  noclear =>  model  ], # creates just model() ala Class::Struct

   get_set => [  java =>[("Contents",   # creates getContents() and setContents()

                          "Heading")]  # creates getHeading() and setHeading()

              ];

You can also design your own get_set method templates, but I won't go into 

the syntax here. Suffice it to say that if you have an accessor mutator scheme in 

mind, Class::MethodMaker can save you the trouble of coding it.

Similar flexibility is available for the generated constructor. When using 

Class::Struct, doing anything at all during object creation requires you to replace 

the generated new() method. Class::MethodMaker has a more elegant solution:

package BOA::Probe;

use Class::MethodMaker

   new_with_init =>  new ,

   get_set       => [ qw(id model contents heading status) ];

# called from the generated new()

sub init {

   my $self = shift;

   croak("Required id parameter missing!") unless @_;

   $self >id(shift);

   return $self;

}

Using new_with_init creates a constructor that calls init() in your module. You 

receive as arguments the arguments passed to new(). One thing you might want to 

do with init() is take a list of key value pairs and assign their values to the named 

attributes. With Class::MethodMaker you can actually auto generate a constructor 

that does this too:

package BOA::Probe;

use Class::MethodMaker

   new_hash_init =>  new ,

   get_set       => [ qw(id model contents heading status) ];

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