/ 
Class-IntrospectionMethods-1.003
River stage zero No dependents
/ Class::IntrospectionMethods::Parent

NAME

Class::IntrospectionMethods::Parent - Handles parent relationship for Class::IntrospectionMethods

SYNOPSIS

No synopsis. Directly used by Class::IntrospectionMethods

DESCRIPTION

This class handles parent relationship for Class::IntrospectionMethods.

In other word, for any child object managed by Class::IntrospectionMethods, it will :

  • Create a ParentInfo object that contains

    • the parent object ref (weakened by Scalar::Util weaken function)

    • The slot name containing the child

    • The index of the element containing the child if the slot is array or hash based.

  • Install a function/method in child's class to retrieve the ParentInfo object.

  • An attribute in child to store the ParentInfo's ref.

By default, the name of the installed function and arribute is cim_parent but this can be changed by calling set_parent_method_name.

Exported functions

set_parent_method_name( name )

This function changes the name of the function and attribute names installed by graft_parent_method. (cim_parent by default)

graft_parent_method( child, parent, slot, [index] )

Creates the ParentInfo object, install the cim_parent function in child's class, store the ParentInfo in child object, finally store slot and index in ParentInfo object.

ParentInfo class

A ParentInfo object is created each time the graft_parent_method function is called.

When, needed, this object is retrieved by calling:

$child->cim_parent

The the following methods may be applied to retrive the informations stored durung graft_parent_method call:

index_value

Returns the index value of the element containing the child object. Returns undex if the Class::IntrospectionMethods slot is not hash or array based.

index_value

Identical to index_value. This method may be preferred for hash based slots. (This is just syntactical sugar).

slot_name

Returns the name of the IntrospectionMethods slot containing the child object.

parent

Returns the parent object containing child.

EXAMPLE

package X ;

use Class::IntrospectionMethods 
  qw/make_methods set_parent_method_name/;

set_parent_method_name('metadad') ;

make_methods
  (
   'parent',

   hash => 
   [
    a => {
	  tie_hash      => ['MyHash', dummy => 'booh'],
	  class_storage => ['MyObj', 'a' => 'foo']
	 },
   ],

   new => 'new' 
  );

package main;

my $o = new X;

my $obj = $o->a('foo') ;
my $info = $obj->metadad ;

my $p= $info->parent; # $p is $o
print $info->slot_name; # -> 'a'
print $info->index_value; # -> 'foo'

# check parent method on object behind tied hash
my $tied_hash_obj = $o->tied_hash_a ;
my $p2 = $tied_hash_obj->metadad->parent; # $p2 is $o

COPYRIGHT

Copyright (c) 2004 Dominique Dumont. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

L<Class::IntrospectionMethods>