package Class::Accessor::Grouped;
use strict;
use warnings;
use Carp ();
use Class::Inspector ();
use Scalar::Util ();
use MRO::Compat;
our $VERSION = '0.08001';
=head1 NAME
Class::Accessor::Grouped - Lets you build groups of accessors
=head1 SYNOPSIS
=head1 DESCRIPTION
This class lets you build groups of accessors that will call different
getters and setters.
=head1 METHODS
=head2 mk_group_accessors
=over 4
=item Arguments: $group, @fieldspec
Returns: none
=back
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, $field ].
=cut
sub mk_group_accessors {
my ($self, $group, @fields) = @_;
$self->_mk_group_accessors('make_group_accessor', $group, @fields);
return;
}
{
no strict 'refs';
no warnings 'redefine';
sub _mk_group_accessors {
my($self, $maker, $group, @fields) = @_;
my $class = Scalar::Util::blessed $self || $self;
$maker = $self->can($maker) unless ref $maker;
foreach my $field (@fields) {
if( $field eq 'DESTROY' ) {
Carp::carp("Having a data accessor named DESTROY in ".
"'$class' is unwise.");
}
my $name = $field;
($name, $field) = @$field if ref $field;
my $accessor = $self->$maker($group, $field);
my $alias = "_${name}_accessor";
*{$class."\:\:$name"} = $accessor;
*{$class."\:\:$alias"} = $accessor;
}
}
}
=head2 mk_group_ro_accessors
=over 4
=item Arguments: $group, @fieldspec
Returns: none
=back
Creates a set of read only accessors in a given group. Identical to
<L:/mk_group_accessors> but accessors will throw an error if passed a value
rather than setting the value.
=cut
sub mk_group_ro_accessors {
my($self, $group, @fields) = @_;
$self->_mk_group_accessors('make_group_ro_accessor', $group, @fields);
}
=head2 mk_group_wo_accessors
=over 4
=item Arguments: $group, @fieldspec
Returns: none
=back
Creates a set of write only accessors in a given group. Identical to
<L:/mk_group_accessors> but accessors will throw an error if not passed a
value rather than getting the value.
=cut
sub mk_group_wo_accessors {
my($self, $group, @fields) = @_;
$self->_mk_group_accessors('make_group_wo_accessor', $group, @fields);
}
=head2 make_group_accessor
=over 4
=item Arguments: $group, $field
Returns: $sub (\CODE)
=back
Returns a single accessor in a given group; called by mk_group_accessors
for each entry in @fieldspec.
=cut
sub make_group_accessor {
my ($class, $group, $field) = @_;
my $set = "set_$group";
my $get = "get_$group";
return eval "sub {
if(\@_ > 1) {
return shift->$set('$field', \@_);
}
else {
return shift->$get('$field');
}
};"
}
=head2 make_group_ro_accessor
=over 4
=item Arguments: $group, $field
Returns: $sub (\CODE)
=back
Returns a single read-only accessor in a given group; called by
mk_group_ro_accessors for each entry in @fieldspec.
=cut
sub make_group_ro_accessor {
my($class, $group, $field) = @_;
my $get = "get_$group";
return eval "sub {
if(\@_ > 1) {
my \$caller = caller;
Carp::croak(\"'\$caller' cannot alter the value of '$field' on \".
\"objects of class '$class'\");
}
else {
return shift->$get('$field');
}
};"
}
=head2 make_group_wo_accessor
=over 4
=item Arguments: $group, $field
Returns: $sub (\CODE)
=back
Returns a single write-only accessor in a given group; called by
mk_group_wo_accessors for each entry in @fieldspec.
=cut
sub make_group_wo_accessor {
my($class, $group, $field) = @_;
my $set = "set_$group";
return eval "sub {
unless (\@_ > 1) {
my \$caller = caller;
Carp::croak(\"'\$caller' cannot access the value of '$field' on \".
\"objects of class '$class'\");
}
else {
return shift->$set('$field', \@_);
}
};"
}
=head2 get_simple
=over 4
=item Arguments: $field
Returns: $value
=back
Simple getter for hash-based objects which returns the value for the field
name passed as an argument.
=cut
sub get_simple {
my ($self, $get) = @_;
return $self->{$get};
return $_[0]->{$_[1]};
}
=head2 set_simple
=over 4
=item Arguments: $field, $new_value
Returns: $new_value
=back
Simple setter for hash-based objects which sets and then returns the value
for the field name passed as an argument.
=cut
sub set_simple {
return $_[0]->{$_[1]} = $_[2];
}
=head2 get_inherited
=over 4
=item Arguments: $field
Returns: $value
=back
Simple getter for Classes and hash-based objects which returns the value for
the field name passed as an argument. This behaves much like
L<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.
=cut
sub get_inherited {
my $class;
if (Scalar::Util::blessed $_[0]) {
my $reftype = Scalar::Util::reftype $_[0];
$class = ref $_[0];
if ($reftype eq 'HASH' && exists $_[0]->{$_[1]}) {
return $_[0]->{$_[1]};
} elsif ($reftype ne 'HASH') {
Carp::croak('Cannot get inherited value on an object instance that is not hash-based');
};
} else {
$class = $_[0];
};
no strict 'refs';
return ${$class.'::__cag_'.$_[1]} if defined(${$class.'::__cag_'.$_[1]});
if (!@{$class.'::__cag_supers'}) {
@{$class.'::__cag_supers'} = $_[0]->get_super_paths;
};
foreach (@{$class.'::__cag_supers'}) {
return ${$_.'::__cag_'.$_[1]} if defined(${$_.'::__cag_'.$_[1]});
};
return undef;
}
=head2 set_inherited
=over 4
=item Arguments: $field, $new_value
Returns: $new_value
=back
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.
B<Note:>: This method will die if you try to set an object variable on a non
hash-based object.
=cut
sub set_inherited {
if (Scalar::Util::blessed $_[0]) {
if (Scalar::Util::reftype $_[0] eq 'HASH') {
return $_[0]->{$_[1]} = $_[2];
} else {
Carp::croak('Cannot set inherited value on an object instance that is not hash-based');
};
} else {
no strict 'refs';
return ${$_[0].'::__cag_'.$_[1]} = $_[2];
};
}
=head2 get_component_class
=over 4
=item Arguments: $field
Returns: $value
=back
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();
=cut
sub get_component_class {
return $_[0]->get_inherited($_[1]);
};
=head2 set_component_class
=over 4
=item Arguments: $field, $class
Returns: $new_value
=back
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');
$self->result_class->method();
=cut
sub set_component_class {
if ($_[2]) {
local $^W = 0;
if (Class::Inspector->installed($_[2]) && !Class::Inspector->loaded($_[2])) {
eval "use $_[2]";
Carp::croak("Could not load $_[1] '$_[2]': ", $@) if $@;
};
};
return $_[0]->set_inherited($_[1], $_[2]);
};
=head2 get_super_paths
Returns a list of 'parent' or 'super' class names that the current class inherited from.
=cut
sub get_super_paths {
my $class = Scalar::Util::blessed $_[0] || $_[0];
return @{mro::get_linear_isa($class)};
};
1;
=head1 AUTHORS
Matt S. Trout <mst@shadowcatsystems.co.uk>
Christopher H. Laco <claco@chrislaco.com>
=head1 LICENSE
You may distribute this code under the same terms as Perl itself.
=cut