| Class::MOP::Instance - phpMan
Class::MOP::Instance(3pm) User Contributed Perl Documentation Class::MOP::Instance(3pm)
NAME
Class::MOP::Instance - Instance Meta Object
VERSION
version 2.1213
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.
AUTHORS
· Stevan Little <stevan.little AT iinteractive.com>
· Dave Rolsky <autarch AT urth.org>
· Jesse Luehrs <doy AT tozt.net>
· Shawn M Moore <code AT sartak.org>
· XXXX XXX'XX (Yuval Kogman) <nothingmuch AT woobling.org>
· Karen Etheridge <ether AT cpan.org>
· Florian Ragwitz <rafl AT debian.org>
· Hans Dieter Pearcey <hdp AT weftsoar.net>
· Chris Prather <chris AT prather.org>
· Matt S Trout <mst AT shadowcat.uk>
COPYRIGHT AND LICENSE
This software is copyright (c) 2006 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 v5.20.1 2014-09-25 Class::MOP::Instance(3pm)
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