Commit | Line | Data |
24869f62 |
1 | |
2 | package Class::MOP::Instance; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
9fa4d0b4 |
7 | use Scalar::Util 'weaken'; |
24869f62 |
8 | |
9 | our $VERSION = '0.01'; |
10 | |
11 | sub meta { |
12 | require Class::MOP::Class; |
13 | Class::MOP::Class->initialize(blessed($_[0]) || $_[0]); |
14 | } |
15 | |
16 | sub new { |
052c2a1a |
17 | my ($class, $meta, @attrs) = @_; |
c57c8b10 |
18 | my @slots = map { $_->slots } @attrs; |
24869f62 |
19 | bless { |
fc3ddd1d |
20 | # NOTE: |
21 | # I am not sure that it makes |
22 | # sense to pass in the meta |
23 | # The ideal would be to just |
24 | # pass in the class name, but |
25 | # that is placing too much of |
26 | # an assumption on bless(), |
27 | # which is *probably* a safe |
28 | # assumption,.. but you can |
29 | # never tell <:) |
49c93440 |
30 | meta => $meta, |
052c2a1a |
31 | slots => \@slots, |
24869f62 |
32 | } => $class; |
33 | } |
34 | |
49c93440 |
35 | sub create_instance { |
36 | my $self = shift; |
37 | $self->bless_instance_structure({}); |
2d711cc8 |
38 | } |
39 | |
49c93440 |
40 | sub bless_instance_structure { |
41 | my ($self, $instance_structure) = @_; |
42 | bless $instance_structure, $self->{meta}->name; |
2d711cc8 |
43 | } |
44 | |
45 | # operations on meta instance |
46 | |
eb49acde |
47 | sub get_all_slots { |
48 | my $self = shift; |
49c93440 |
49 | return @{$self->{slots}}; |
839ea973 |
50 | } |
51 | |
2d711cc8 |
52 | # operations on created instances |
53 | |
839ea973 |
54 | sub get_slot_value { |
2bab2be6 |
55 | my ($self, $instance, $slot_name) = @_; |
56 | return $instance->{$slot_name}; |
839ea973 |
57 | } |
58 | |
2bab2be6 |
59 | sub set_slot_value { |
60 | my ($self, $instance, $slot_name, $value) = @_; |
61 | $instance->{$slot_name} = $value; |
62 | } |
63 | |
2d711cc8 |
64 | sub initialize_slot { |
49c93440 |
65 | my ($self, $instance, $slot_name) = @_; |
66 | $instance->{$slot_name} = undef; |
2d711cc8 |
67 | } |
68 | |
c174112e |
69 | sub initialize_all_slots { |
70 | my ($self, $instance) = @_; |
71 | foreach my $slot_name ($self->get_all_slots) { |
72 | $self->initialize_slot($instance, $slot_name); |
73 | } |
74 | } |
75 | |
49c93440 |
76 | sub is_slot_initialized { |
77 | my ($self, $instance, $slot_name, $value) = @_; |
2d711cc8 |
78 | exists $instance->{$slot_name} ? 1 : 0; |
2bab2be6 |
79 | } |
839ea973 |
80 | |
5582521c |
81 | sub set_slot_value_weak { |
82 | my ($self, $instance, $slot_name, $value) = @_; |
83 | $self->set_slot_value($instance, $slot_name, $value); |
84 | $self->weaken_slot_value($instance, $slot_name); |
85 | } |
86 | |
87 | sub weaken_slot_value { |
88 | my ($self, $instance, $slot_name) = @_; |
89 | weaken $instance->{$slot_name}; |
90 | } |
91 | |
92 | sub strengthen_slot_value { |
93 | my ($self, $instance, $slot_name) = @_; |
94 | $self->set_slot_value($instance, $slot_name, $self->get_slot_value($instance, $slot_name)); |
95 | } |
96 | |
24869f62 |
97 | 1; |
98 | |
99 | __END__ |
100 | |
101 | =pod |
102 | |
103 | =head1 NAME |
104 | |
105 | Class::MOP::Instance - Instance Meta Object |
106 | |
107 | =head1 SYNOPSIS |
108 | |
9fa4d0b4 |
109 | # for the most part, this protocol is internal |
110 | # and not for public usage, but this how one |
111 | # might use it |
112 | |
113 | package Foo; |
114 | |
115 | use strict; |
116 | use warnings; |
1becdfcc |
117 | use metaclass ( |
9fa4d0b4 |
118 | ':instance_metaclass' => 'ArrayBasedStorage::Instance', |
119 | ); |
120 | |
121 | # now Foo->new produces blessed ARRAY ref based objects |
122 | |
24869f62 |
123 | =head1 DESCRIPTION |
124 | |
9fa4d0b4 |
125 | This is a sub-protocol which governs instance creation |
126 | and access to the slots of the instance structure. |
127 | |
128 | This may seem like over-abstraction, but by abstracting |
129 | this process into a sub-protocol we make it possible to |
130 | easily switch the details of how an object's instance is |
131 | stored with minimal impact. In most cases just subclassing |
1becdfcc |
132 | this class will be all you need to do (see the examples; |
133 | F<examples/ArrayBasedStorage.pod> and |
134 | F<examples/InsideOutClass.pod> for details). |
9fa4d0b4 |
135 | |
24869f62 |
136 | =head1 METHODS |
137 | |
138 | =over 4 |
139 | |
9fa4d0b4 |
140 | =item B<new ($meta, @attrs)> |
141 | |
142 | Creates a new instance meta-object and gathers all the slots from |
143 | the list of C<@attrs> given. |
144 | |
145 | =item B<meta> |
146 | |
147 | This will return a B<Class::MOP::Class> instance which is related |
148 | to this class. |
149 | |
150 | =back |
151 | |
152 | =head2 Creation of Instances |
153 | |
154 | =over 4 |
24869f62 |
155 | |
58287a97 |
156 | =item B<create_instance> |
157 | |
9fa4d0b4 |
158 | This creates the appropriate structure needed for the instance and |
159 | then calls C<bless_instance_structure> to bless it into the class. |
0e76a376 |
160 | |
9fa4d0b4 |
161 | =item B<bless_instance_structure ($instance_structure)> |
839ea973 |
162 | |
9fa4d0b4 |
163 | This does just exactly what it says it does. |
0e76a376 |
164 | |
9fa4d0b4 |
165 | =back |
839ea973 |
166 | |
9fa4d0b4 |
167 | =head2 Instrospection |
58287a97 |
168 | |
9fa4d0b4 |
169 | NOTE: There might be more methods added to this part of the API, |
170 | we will add then when we need them basically. |
58287a97 |
171 | |
9fa4d0b4 |
172 | =over 4 |
173 | |
174 | =item B<get_all_slots> |
175 | |
176 | This will return the current list of slots based on what was |
177 | given to this object in C<new>. |
58287a97 |
178 | |
24869f62 |
179 | =back |
180 | |
9fa4d0b4 |
181 | =head2 Operations on Instance Structures |
182 | |
183 | An important distinction of this sub-protocol is that the |
184 | instance meta-object is a different entity from the actual |
185 | instance it creates. For this reason, any actions on slots |
186 | require that the C<$instance_structure> is passed into them. |
24869f62 |
187 | |
188 | =over 4 |
189 | |
9fa4d0b4 |
190 | =item B<get_slot_value ($instance_structure, $slot_name)> |
24869f62 |
191 | |
9fa4d0b4 |
192 | =item B<set_slot_value ($instance_structure, $slot_name, $value)> |
193 | |
194 | =item B<initialize_slot ($instance_structure, $slot_name)> |
195 | |
196 | =item B<initialize_all_slots ($instance_structure)> |
197 | |
198 | =item B<is_slot_initialized ($instance_structure, $slot_name)> |
24869f62 |
199 | |
5582521c |
200 | =item B<set_slot_value_weak ($instance_structure, $slot_name, $ref_value)> |
201 | |
202 | =item B<weaken_slot_value> |
203 | |
204 | =item B<strengthen_slot_value> |
205 | |
24869f62 |
206 | =back |
207 | |
208 | =head1 AUTHOR |
209 | |
9fa4d0b4 |
210 | Yuval Kogman E<lt>nothingmuch@woobling.comE<gt> |
211 | |
24869f62 |
212 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
213 | |
214 | =head1 COPYRIGHT AND LICENSE |
215 | |
216 | Copyright 2006 by Infinity Interactive, Inc. |
217 | |
218 | L<http://www.iinteractive.com> |
219 | |
220 | This library is free software; you can redistribute it and/or modify |
221 | it under the same terms as Perl itself. |
222 | |
84ef30d1 |
223 | =cut |
5582521c |
224 | |