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Class::MOP::Instance(3)              User Contributed Perl Documentation             Class::MOP::Instance(3)



NAME
       Class::MOP::Instance - Instance Meta Object

VERSION
       version 2.0205

DESCRIPTION
       The Instance Protocol controls the creation of object instances, and the storage of attribute values
       in those instances.

       Using this API directly in your own code violates encapsulation, and we recommend that you use the
       appropriate APIs in Class::MOP::Class and Class::MOP::Attribute instead. Those APIs in turn call the
       methods in this class as appropriate.

       This class also participates in generating inlined code by providing snippets of code to access an
       object instance.

METHODS
   Object construction
       Class::MOP::Instance->new(%options)
           This method creates a new meta-instance object.

           It accepts the following keys in %options:

           •       associated_metaclass

                   The Class::MOP::Class object for which instances will be created.

           •       attributes

                   An array reference of Class::MOP::Attribute objects. These are the attributes which can
                   be stored in each instance.

   Creating and altering instances
       $metainstance->create_instance
           This method returns a reference blessed into the associated metaclass's class.

           The default is to use a hash reference. Subclasses can override this.

       $metainstance->clone_instance($instance)
           Given an instance, this method creates a new object by making shallow clone of the original.

   Introspection
       $metainstance->associated_metaclass
           This returns the Class::MOP::Class object associated with the meta-instance object.

       $metainstance->get_all_slots
           This returns a list of slot names stored in object instances. In almost all cases, slot names
           correspond directly attribute names.

       $metainstance->is_valid_slot($slot_name)
           This will return true if $slot_name is a valid slot name.

       $metainstance->get_all_attributes
           This returns a list of attributes corresponding to the attributes passed to the constructor.

   Operations on Instance Structures
       It's important to understand that the meta-instance object is a different entity from the actual
       instances it creates. For this reason, any operations on the $instance_structure always require that
       the object instance be passed to the method.

       $metainstance->get_slot_value($instance_structure, $slot_name)
       $metainstance->set_slot_value($instance_structure, $slot_name, $value)
       $metainstance->initialize_slot($instance_structure, $slot_name)
       $metainstance->deinitialize_slot($instance_structure, $slot_name)
       $metainstance->initialize_all_slots($instance_structure)
       $metainstance->deinitialize_all_slots($instance_structure)
       $metainstance->is_slot_initialized($instance_structure, $slot_name)
       $metainstance->weaken_slot_value($instance_structure, $slot_name)
       $metainstance->slot_value_is_weak($instance_structure, $slot_name)
       $metainstance->strengthen_slot_value($instance_structure, $slot_name)
       $metainstance->rebless_instance_structure($instance_structure, $new_metaclass)
           The exact details of what each method does should be fairly obvious from the method name.

   Inlinable Instance Operations
       $metainstance->is_inlinable
           This is a boolean that indicates whether or not slot access operations can be inlined. By default
           it is true, but subclasses can override this.

       $metainstance->inline_create_instance($class_variable)
           This method expects a string that, when inlined, will become a class name. This would literally
           be something like '$class', not an actual class name.

           It returns a snippet of code that creates a new object for the class. This is something like "
           bless {}, $class_name ".

       $metainstance->inline_get_is_lvalue
           Returns whether or not "inline_get_slot_value" is a valid lvalue. This can be used to do extra
           optimizations when generating inlined methods.

       $metainstance->inline_slot_access($instance_variable, $slot_name)
       $metainstance->inline_get_slot_value($instance_variable, $slot_name)
       $metainstance->inline_set_slot_value($instance_variable, $slot_name, $value)
       $metainstance->inline_initialize_slot($instance_variable, $slot_name)
       $metainstance->inline_deinitialize_slot($instance_variable, $slot_name)
       $metainstance->inline_is_slot_initialized($instance_variable, $slot_name)
       $metainstance->inline_weaken_slot_value($instance_variable, $slot_name)
       $metainstance->inline_strengthen_slot_value($instance_variable, $slot_name)
           These methods all expect two arguments. The first is the name of a variable, than when inlined,
           will represent the object instance. Typically this will be a literal string like '$_[0]'.

           The second argument is a slot name.

           The method returns a snippet of code that, when inlined, performs some operation on the instance.

       $metainstance->inline_rebless_instance_structure($instance_variable, $class_variable)
           This takes the name of a variable that will, when inlined, represent the object instance, and the
           name of a variable that will represent the class to rebless into, and returns code to rebless an
           instance into a class.

   Introspection
       Class::MOP::Instance->meta
           This will return a Class::MOP::Class instance for this class.

           It should also be noted that Class::MOP will actually bootstrap this module by installing a
           number of attribute meta-objects into its metaclass.

AUTHOR
       Stevan Little <stevan@iinteractive.com>

COPYRIGHT AND LICENSE
       This software is copyright (c) 2011 by Infinity Interactive, Inc..

       This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5
       programming language system itself.



perl v5.12.5                                     2011-09-06                          Class::MOP::Instance(3)