plucky (3) Class::Accessor::Grouped.3pm.gz
NAME
Class::Accessor::Grouped - Lets you build groups of accessors
SYNOPSIS
use base 'Class::Accessor::Grouped';
# make basic accessors for objects
__PACKAGE__->mk_group_accessors(simple => qw(id name email));
# make accessor that works for objects and classes
__PACKAGE__->mk_group_accessors(inherited => 'awesome_level');
# make an accessor which calls a custom pair of getters/setters
sub get_column { ... this will be called when you do $obj->name() ... }
sub set_column { ... this will be called when you do $obj->name('foo') ... }
__PACKAGE__->mk_group_accessors(column => 'name');
DESCRIPTION
This class lets you build groups of accessors that will call different getters and setters. The
documentation of this module still requires a lot of work (volunteers welcome >.>), but in the meantime
you can refer to this post <http://lo-f.at/glahn/2009/08/WritingPowerfulAccessorsForPerlClasses.html> for
more information.
Notes on accessor names
In general method names in Perl are considered identifiers, and as such need to conform to the identifier
specification of "qr/\A[A-Z_a-z][0-9A-Z_a-z]*\z/". While it is rather easy to invoke methods with non-
standard names ("$obj->${\"anything goes"}"), it is not possible to properly declare such methods without
the use of Sub::Name. Since this module must be able to function identically with and without its
optional dependencies, starting with version 0.10008 attempting to declare an accessor with a non-
standard name is a fatal error (such operations would silently succeed since version 0.08004, as long as
Sub::Name is present, or otherwise would result in a syntax error during a string eval).
Unfortunately in the years since 0.08004 a rather large body of code accumulated in the wild that does
attempt to declare accessors with funny names. One notable perpetrator is DBIx::Class::Schema::Loader,
which under certain conditions could create accessors of the "column" group which start with numbers
and/or some other punctuation (the proper way would be to declare columns with the "accessor" attribute
set to "undef").
Therefore an escape mechanism is provided via the environment variable "CAG_ILLEGAL_ACCESSOR_NAME_OK".
When set to a true value, one warning is issued per class on attempts to declare an accessor with a non-
conforming name, and as long as Sub::Name is available all accessors will be properly created. Regardless
of this setting, accessor names containing nulls "\0" are disallowed, due to various deficiencies in perl
itself.
If your code base has too many instances of illegal accessor declarations, and a fix is not feasible due
to time constraints, it is possible to disable the warnings altogether by setting
$ENV{CAG_ILLEGAL_ACCESSOR_NAME_OK} to "DO_NOT_WARN" (observe capitalization).
METHODS
mk_group_accessors
__PACKAGE__->mk_group_accessors(simple => 'hair_length', [ hair_color => 'hc' ]);
Arguments: $group, @fieldspec
Returns: none
Creates a set of accessors in a given group.
$group is the name of the accessor group for the generated accessors; they will call get_$group($field)
on get and set_$group($field, $value) on set.
If you want to mimic Class::Accessor's mk_accessors $group has to be 'simple' to tell
Class::Accessor::Grouped to use its own get_simple and set_simple methods.
@fieldspec is a list of field/accessor names; if a fieldspec is a scalar this is used as both field and
accessor name, if a listref it is expected to be of the form [ $accessor, $field ].
mk_group_ro_accessors
__PACKAGE__->mk_group_ro_accessors(simple => 'birthdate', [ social_security_number => 'ssn' ]);
Arguments: $group, @fieldspec
Returns: none
Creates a set of read only accessors in a given group. Identical to "mk_group_accessors" but accessors
will throw an error if passed a value rather than setting the value.
mk_group_wo_accessors
__PACKAGE__->mk_group_wo_accessors(simple => 'lie', [ subject => 'subj' ]);
Arguments: $group, @fieldspec
Returns: none
Creates a set of write only accessors in a given group. Identical to "mk_group_accessors" but accessors
will throw an error if not passed a value rather than getting the value.
get_simple
Arguments: $field
Returns: $value
Simple getter for hash-based objects which returns the value for the field name passed as an argument.
set_simple
Arguments: $field, $new_value
Returns: $new_value
Simple setter for hash-based objects which sets and then returns the value for the field name passed as
an argument.
get_inherited
Arguments: $field
Returns: $value
Simple getter for Classes and hash-based objects which returns the value for the field name passed as an
argument. This behaves much like Class::Data::Accessor where the field can be set in a base class,
inherited and changed in subclasses, and inherited and changed for object instances.
set_inherited
Arguments: $field, $new_value
Returns: $new_value
Simple setter for Classes and hash-based objects which sets and then returns the value for the field name
passed as an argument. When called on a hash-based object it will set the appropriate hash key value.
When called on a class, it will set a class level variable.
Note:: This method will die if you try to set an object variable on a non hash-based object.
get_component_class
Arguments: $field
Returns: $value
Gets the value of the specified component class.
__PACKAGE__->mk_group_accessors('component_class' => 'result_class');
$self->result_class->method();
## same as
$self->get_component_class('result_class')->method();
set_component_class
Arguments: $field, $class
Returns: $new_value
Inherited accessor that automatically loads the specified class before setting it. This method will die
if the specified class could not be loaded.
__PACKAGE__->mk_group_accessors('component_class' => 'result_class');
__PACKAGE__->result_class('MyClass');
$self->result_class->method();
INTERNAL METHODS
These methods are documented for clarity, but are never meant to be called directly, and are not really
meant for overriding either.
get_super_paths
Returns a list of 'parent' or 'super' class names that the current class inherited from. This is what
drives the traversal done by "get_inherited".
make_group_accessor
__PACKAGE__->make_group_accessor('simple', 'hair_length', 'hair_length');
__PACKAGE__->make_group_accessor('simple', 'hc', 'hair_color');
Arguments: $group, $field, $accessor
Returns: \&accessor_coderef ?
Called by mk_group_accessors for each entry in @fieldspec. Either returns a coderef which will be
installed at "&__PACKAGE__::$accessor", or returns "undef" if it elects to install the coderef on its
own.
make_group_ro_accessor
__PACKAGE__->make_group_ro_accessor('simple', 'birthdate', 'birthdate');
__PACKAGE__->make_group_ro_accessor('simple', 'ssn', 'social_security_number');
Arguments: $group, $field, $accessor
Returns: \&accessor_coderef ?
Called by mk_group_ro_accessors for each entry in @fieldspec. Either returns a coderef which will be
installed at "&__PACKAGE__::$accessor", or returns "undef" if it elects to install the coderef on its
own.
make_group_wo_accessor
__PACKAGE__->make_group_wo_accessor('simple', 'lie', 'lie');
__PACKAGE__->make_group_wo_accessor('simple', 'subj', 'subject');
Arguments: $group, $field, $accessor
Returns: \&accessor_coderef ?
Called by mk_group_wo_accessors for each entry in @fieldspec. Either returns a coderef which will be
installed at "&__PACKAGE__::$accessor", or returns "undef" if it elects to install the coderef on its
own.
PERFORMANCE
To provide total flexibility Class::Accessor::Grouped calls methods internally while performing get/set
actions, which makes it noticeably slower than similar modules. To compensate, this module will
automatically use the insanely fast Class::XSAccessor to generate the "simple"-group accessors if this
module is available on your system.
Benchmark
This is the benchmark of 200 get/get/set/get/set cycles on perl 5.16.2 with thread support, showcasing
how this modules simple (CAG_S), inherited (CAG_INH) and inherited with parent-class data (CAG_INHP)
accessors stack up against most popular accessor builders: Moose, Moo, Mo, Mouse (both pure-perl and XS
variant), Object::Tiny::RW (OTRW), Class::Accessor (CA), Class::Accessor::Lite (CAL),
Class::Accessor::Fast (CAF), Class::Accessor::Fast::XS (CAF_XS) and Class::XSAccessor (XSA)
Rate CAG_INHP CAG_INH CA CAG_S CAF moOse OTRW CAL mo moUse HANDMADE moo CAF_XS moUse_XS XSA
CAG_INHP 287.021+-0.02/s -- -0.3% -10.0% -37.1% -53.1% -53.6% -53.7% -54.1% -56.9% -59.0% -59.6% -59.8% -78.7% -81.9% -83.5%
CAG_INH 288.025+-0.031/s 0.3% -- -9.7% -36.9% -52.9% -53.5% -53.5% -53.9% -56.7% -58.8% -59.5% -59.7% -78.6% -81.9% -83.5%
CA 318.967+-0.047/s 11.1% 10.7% -- -30.1% -47.9% -48.5% -48.5% -49.0% -52.1% -54.4% -55.1% -55.3% -76.3% -79.9% -81.7%
CAG_S 456.107+-0.054/s 58.9% 58.4% 43.0% -- -25.4% -26.3% -26.4% -27.0% -31.5% -34.8% -35.8% -36.1% -66.1% -71.3% -73.9%
CAF 611.745+-0.099/s 113.1% 112.4% 91.8% 34.1% -- -1.2% -1.2% -2.1% -8.1% -12.6% -14.0% -14.3% -54.5% -61.5% -64.9%
moOse 619.051+-0.059/s 115.7% 114.9% 94.1% 35.7% 1.2% -- -0.1% -1.0% -7.0% -11.6% -12.9% -13.3% -54.0% -61.0% -64.5%
OTRW 619.475+-0.1/s 115.8% 115.1% 94.2% 35.8% 1.3% 0.1% -- -0.9% -6.9% -11.5% -12.9% -13.2% -54.0% -61.0% -64.5%
CAL 625.106+-0.085/s 117.8% 117.0% 96.0% 37.1% 2.2% 1.0% 0.9% -- -6.1% -10.7% -12.1% -12.5% -53.5% -60.6% -64.2%
mo 665.44+-0.12/s 131.8% 131.0% 108.6% 45.9% 8.8% 7.5% 7.4% 6.5% -- -4.9% -6.4% -6.8% -50.5% -58.1% -61.9%
moUse 699.9+-0.15/s 143.9% 143.0% 119.4% 53.5% 14.4% 13.1% 13.0% 12.0% 5.2% -- -1.6% -2.0% -48.0% -55.9% -59.9%
HANDMADE 710.98+-0.16/s 147.7% 146.8% 122.9% 55.9% 16.2% 14.9% 14.8% 13.7% 6.8% 1.6% -- -0.4% -47.2% -55.2% -59.2%
moo 714.04+-0.13/s 148.8% 147.9% 123.9% 56.6% 16.7% 15.3% 15.3% 14.2% 7.3% 2.0% 0.4% -- -46.9% -55.0% -59.1%
CAF_XS 1345.55+-0.051/s 368.8% 367.2% 321.8% 195.0% 120.0% 117.4% 117.2% 115.3% 102.2% 92.2% 89.3% 88.4% -- -15.3% -22.9%
moUse_XS 1588+-0.036/s 453.3% 451.3% 397.9% 248.2% 159.6% 156.5% 156.3% 154.0% 138.6% 126.9% 123.4% 122.4% 18.0% -- -9.0%
XSA 1744.67+-0.052/s 507.9% 505.7% 447.0% 282.5% 185.2% 181.8% 181.6% 179.1% 162.2% 149.3% 145.4% 144.3% 29.7% 9.9% --
Benchmarking program is available in the root of the repository <http://search.cpan.org/dist/Class-
Accessor-Grouped/>:
Notes on Class::XSAccessor
You can force (or disable) the use of Class::XSAccessor before creating a particular "simple" accessor by
either manipulating the global variable $Class::Accessor::Grouped::USE_XS to true or false (preferably
with localization, or you can do so before runtime via the "CAG_USE_XS" environment variable.
Since Class::XSAccessor has no knowledge of "get_simple" and "set_simple" this module does its best to
detect if you are overriding one of these methods and will fall back to using the perl version of the
accessor in order to maintain consistency. However be aware that if you enable use of "Class::XSAccessor"
(automatically or explicitly), create an object, invoke a simple accessor on that object, and then
manipulate the symbol table to install a "get/set_simple" override - you get to keep all the pieces.
AUTHORS
Matt S. Trout <mst@shadowcatsystems.co.uk> Christopher H. Laco <claco@chrislaco.com>
CONTRIBUTORS
Caelum: Rafael Kitover <rkitover@cpan.org> frew: Arthur Axel "fREW" Schmidt <frioux@gmail.com> groditi: Guillermo Roditi <groditi@cpan.org> Jason Plum <jason.plum@bmmsi.com> ribasushi: Peter Rabbitson <ribasushi@cpan.org>
COPYRIGHT & LICENSE
Copyright (c) 2006-2010 Matt S. Trout <mst@shadowcatsystems.co.uk> This program is free software; you can redistribute it and/or modify it under the same terms as perl itself.