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471c4f09 |
1 | |
2 | =pod |
3 | |
5547fba7 |
4 | =begin testing-SETUP |
c79239a2 |
5 | |
6 | BEGIN { |
7 | eval 'use Regexp::Common; use Locale::US;'; |
8 | if ($@) { |
9 | diag 'Regexp::Common & Locale::US required for this test'; |
10 | ok(1); |
11 | exit 0; |
12 | } |
13 | } |
14 | |
5547fba7 |
15 | =end testing-SETUP |
c79239a2 |
16 | |
471c4f09 |
17 | =head1 NAME |
18 | |
021b8139 |
19 | Moose::Cookbook::Basics::Recipe4 - Subtypes, and modeling a simple B<Company> class hierarchy |
471c4f09 |
20 | |
21 | =head1 SYNOPSIS |
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22 | |
471c4f09 |
23 | package Address; |
471c4f09 |
24 | use Moose; |
05d9eaf6 |
25 | use Moose::Util::TypeConstraints; |
36c99105 |
26 | |
471c4f09 |
27 | use Locale::US; |
28 | use Regexp::Common 'zip'; |
36c99105 |
29 | |
471c4f09 |
30 | my $STATES = Locale::US->new; |
0b3811a6 |
31 | subtype 'USState' |
471c4f09 |
32 | => as Str |
33 | => where { |
36c99105 |
34 | ( exists $STATES->{code2state}{ uc($_) } |
35 | || exists $STATES->{state2code}{ uc($_) } ); |
36 | }; |
37 | |
0b3811a6 |
38 | subtype 'USZipCode' |
471c4f09 |
39 | => as Value |
40 | => where { |
36c99105 |
41 | /^$RE{zip}{US}{-extended => 'allow'}$/; |
42 | }; |
43 | |
44 | has 'street' => ( is => 'rw', isa => 'Str' ); |
45 | has 'city' => ( is => 'rw', isa => 'Str' ); |
46 | has 'state' => ( is => 'rw', isa => 'USState' ); |
47 | has 'zip_code' => ( is => 'rw', isa => 'USZipCode' ); |
48 | |
f1917f58 |
49 | package Company; |
50 | use Moose; |
51 | use Moose::Util::TypeConstraints; |
36c99105 |
52 | |
53 | has 'name' => ( is => 'rw', isa => 'Str', required => 1 ); |
54 | has 'address' => ( is => 'rw', isa => 'Address' ); |
55 | has 'employees' => ( is => 'rw', isa => 'ArrayRef[Employee]' ); |
56 | |
f1917f58 |
57 | sub BUILD { |
36c99105 |
58 | my ( $self, $params ) = @_; |
922a97e9 |
59 | foreach my $employee ( @{ $self->employees || [] } ) { |
60 | $employee->employer($self); |
f1917f58 |
61 | } |
62 | } |
36c99105 |
63 | |
f1917f58 |
64 | after 'employees' => sub { |
36c99105 |
65 | my ( $self, $employees ) = @_; |
922a97e9 |
66 | foreach my $employee ( @{ $employees || [] } ) { |
67 | $employee->employer($self); |
f1917f58 |
68 | } |
36c99105 |
69 | }; |
70 | |
471c4f09 |
71 | package Person; |
471c4f09 |
72 | use Moose; |
36c99105 |
73 | |
74 | has 'first_name' => ( is => 'rw', isa => 'Str', required => 1 ); |
75 | has 'last_name' => ( is => 'rw', isa => 'Str', required => 1 ); |
76 | has 'middle_initial' => ( |
77 | is => 'rw', isa => 'Str', |
78 | predicate => 'has_middle_initial' |
79 | ); |
80 | has 'address' => ( is => 'rw', isa => 'Address' ); |
81 | |
471c4f09 |
82 | sub full_name { |
83 | my $self = shift; |
36c99105 |
84 | return $self->first_name |
85 | . ( |
86 | $self->has_middle_initial |
87 | ? ' ' . $self->middle_initial . '. ' |
88 | : ' ' |
89 | ) . $self->last_name; |
471c4f09 |
90 | } |
36c99105 |
91 | |
471c4f09 |
92 | package Employee; |
36c99105 |
93 | use Moose; |
94 | |
471c4f09 |
95 | extends 'Person'; |
36c99105 |
96 | |
4a6b74bd |
97 | has 'title' => ( is => 'rw', isa => 'Str', required => 1 ); |
98 | has 'employer' => ( is => 'rw', isa => 'Company', weak_ref => 1 ); |
36c99105 |
99 | |
471c4f09 |
100 | override 'full_name' => sub { |
101 | my $self = shift; |
36c99105 |
102 | super() . ', ' . $self->title; |
471c4f09 |
103 | }; |
2f04a0fc |
104 | |
471c4f09 |
105 | =head1 DESCRIPTION |
106 | |
4a6b74bd |
107 | This recipe introduces the C<subtype> sugar function from |
108 | L<Moose::Util::TypeConstraints>. The C<subtype> function lets you |
109 | declaratively create type constraints without building an entire |
110 | class. |
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111 | |
4a6b74bd |
112 | In the recipe we also make use of L<Locale::US> and L<Regexp::Common> |
cad0dd79 |
113 | to build constraints, showing how constraints can make use of existing |
114 | CPAN tools for data validation. |
36c99105 |
115 | |
16fb3624 |
116 | Finally, we introduce the C<required> attribute option. |
4a6b74bd |
117 | |
21ec1978 |
118 | In the C<Address> class we define two subtypes. The first uses the |
19320607 |
119 | L<Locale::US> module to check the validity of a state. It accepts |
4a6b74bd |
120 | either a state abbreviation of full name. |
121 | |
122 | A state will be passed in as a string, so we make our C<USState> type |
123 | a subtype of Moose's builtin C<Str> type. This is done using the C<as> |
124 | sugar. The actual constraint is defined using C<where>. This function |
125 | accepts a single subroutine reference. That subroutine will be called |
126 | with the value to be checked in C<$_> (1). It is expected to return a |
127 | true or false value indicating whether the value is valid for the |
128 | type. |
172e0738 |
129 | |
4a6b74bd |
130 | We can now use the C<USState> type just like Moose's builtin types: |
172e0738 |
131 | |
36c99105 |
132 | has 'state' => ( is => 'rw', isa => 'USState' ); |
172e0738 |
133 | |
4a6b74bd |
134 | When the C<state> attribute is set, the value is checked against the |
135 | C<USState> constraint. If the value is not valid, an exception will be |
136 | thrown. |
172e0738 |
137 | |
4a6b74bd |
138 | The next C<subtype>, C<USZipCode>, uses |
139 | L<Regexp::Common>. L<Regexp::Common> includes a regex for validating |
140 | US zip codes. We use this constraint for the C<zip_code> attribute. |
172e0738 |
141 | |
0b3811a6 |
142 | subtype 'USZipCode' |
172e0738 |
143 | => as Value |
144 | => where { |
36c99105 |
145 | /^$RE{zip}{US}{-extended => 'allow'}$/; |
146 | }; |
172e0738 |
147 | |
4a6b74bd |
148 | Using a subtype instead of requiring a class for each type greatly |
149 | simplifies the code. We don't really need a class for these types, as |
150 | they're just strings, but we do want to ensure that they're valid. |
151 | |
152 | The type constraints we created are reusable. Type constraints are |
153 | stored by name in a global registry. This means that we can refer to |
154 | them in other classes. Because the registry is global, we do recommend |
155 | that you use some sort of pseudo-namespacing in real applications, |
156 | like C<MyApp.Type.USState>. |
157 | |
158 | These two subtypes allow us to define a simple C<Address> class. |
172e0738 |
159 | |
4a6b74bd |
160 | Then we define our C<Company> class, which has an address. As we saw |
161 | in earlier recipes, Moose automatically creates a type constraint for |
162 | each our classes, so we can use that for the C<Company> class's |
163 | C<address> attribute: |
172e0738 |
164 | |
36c99105 |
165 | has 'address' => ( is => 'rw', isa => 'Address' ); |
172e0738 |
166 | |
4a6b74bd |
167 | A company also needs a name: |
172e0738 |
168 | |
36c99105 |
169 | has 'name' => ( is => 'rw', isa => 'Str', required => 1 ); |
172e0738 |
170 | |
16fb3624 |
171 | This introduces a new attribute option, C<required>. If an attribute |
172 | is required, then it must be passed to the class's constructor, or an |
173 | exception will be thrown. It's important to understand that a |
174 | C<required> attribute can still be false or C<undef>, if its type |
175 | constraint allows that. |
f1917f58 |
176 | |
4a6b74bd |
177 | The next attribute, C<employees>, uses a I<parameterized> type |
178 | constraint: |
36c99105 |
179 | |
180 | has 'employees' => ( is => 'rw', isa => 'ArrayRef[Employee]' ); |
07cde929 |
181 | |
4a6b74bd |
182 | This constraint says that C<employees> must be an array reference |
183 | where each element of the array is an C<Employee> object. It's worth |
184 | noting that an I<empty> array reference also satisfies this |
185 | constraint. |
186 | |
cad0dd79 |
187 | Parameterizable type constraints (or "container types"), such as |
4a6b74bd |
188 | C<ArrayRef[`a]>, can be made more specific with a type parameter. In |
189 | fact, we can arbitrarily nest these types, producing something like |
190 | C<HashRef[ArrayRef[Int]]>. However, you can also just use the type by |
191 | itself, so C<ArrayRef> is legal. (2) |
192 | |
193 | If you jump down to the definition of the C<Employee> class, you will |
194 | see that it has an C<employer> attribute. |
195 | |
196 | When we set the C<employees> for a C<Company> we want to make sure |
197 | that each of these employee objects refers back to the right |
198 | C<Company> in its C<employer> attribute. |
199 | |
200 | To do that, we need to hook into object construction. Moose lets us do |
201 | this by writing a C<BUILD> method in our class. When your class |
202 | defined a C<BUILD> method, it will be called immediately after an |
203 | object construction, but before the object is returned to the caller |
204 | (3). |
205 | |
206 | The C<Company> class uses the C<BUILD> method to ensure that each |
207 | employee of a company has the proper C<Company> object in its |
208 | C<employer> attribute: |
36c99105 |
209 | |
ad5ed80c |
210 | sub BUILD { |
36c99105 |
211 | my ( $self, $params ) = @_; |
922a97e9 |
212 | foreach my $employee ( @{ $self->employees || [] } ) { |
213 | $employee->employer($self); |
ad5ed80c |
214 | } |
215 | } |
216 | |
922a97e9 |
217 | The C<BUILD> method is executed after type constraints are checked, so it is |
218 | safe to assume that if C<< $self->employees >> has a value, it will be an |
219 | array reference, and that the elements of that array reference will be |
220 | C<Employee> objects. |
4a6b74bd |
221 | |
222 | We also want to make sure that whenever the C<employees> attribute for |
223 | a C<Company> is changed, we also update the C<employer> for each |
224 | employee. |
ad5ed80c |
225 | |
4a6b74bd |
226 | To do this we can use an C<after> modifier: |
ad5ed80c |
227 | |
228 | after 'employees' => sub { |
36c99105 |
229 | my ( $self, $employees ) = @_; |
922a97e9 |
230 | foreach my $employee ( @{ $employees || [] } ) { |
231 | $employee->employer($self); |
ad5ed80c |
232 | } |
233 | }; |
234 | |
922a97e9 |
235 | Again, as with the C<BUILD> method, we know that the type constraint check has |
236 | already happened, so we know that if C<$employees> is defined it will contain |
237 | an array reference of C<Employee> objects.. |
ad5ed80c |
238 | |
fdba9686 |
239 | The B<Person> class does not really demonstrate anything new. It has several |
4a6b74bd |
240 | C<required> attributes. It also has a C<predicate> method, which we |
241 | first used in L<recipe 3|Moose::Cookbook::Basics::Recipe3>. |
f1917f58 |
242 | |
4a6b74bd |
243 | The only new feature in the C<Employee> class is the C<override> |
244 | method modifier: |
f1917f58 |
245 | |
246 | override 'full_name' => sub { |
247 | my $self = shift; |
36c99105 |
248 | super() . ', ' . $self->title; |
f1917f58 |
249 | }; |
250 | |
4a6b74bd |
251 | This is just a sugary alternative to Perl's built in C<SUPER::> |
252 | feature. However, there is one difference. You cannot pass any |
19320607 |
253 | arguments to C<super>. Instead, Moose simply passes the same |
4a6b74bd |
254 | parameters that were passed to the method. |
ad5ed80c |
255 | |
4a6b74bd |
256 | A more detailed example of usage can be found in |
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257 | F<t/000_recipes/moose_cookbook_basics_recipe4.t>. |
ad5ed80c |
258 | |
259 | =head1 CONCLUSION |
260 | |
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261 | This recipe was intentionally longer and more complex. It illustrates |
262 | how Moose classes can be used together with type constraints, as well |
263 | as the density of information that you can get out of a small amount |
264 | of typing when using Moose. |
265 | |
266 | This recipe also introduced the C<subtype> function, the C<required> |
267 | attribute, and the C<override> method modifier. |
ad5ed80c |
268 | |
4a6b74bd |
269 | We will revisit type constraints in future recipes, and cover type |
270 | coercion as well. |
e08c54f5 |
271 | |
172e0738 |
272 | =head1 FOOTNOTES |
273 | |
274 | =over 4 |
275 | |
276 | =item (1) |
277 | |
6549b0d1 |
278 | The value being checked is also passed as the first argument to |
4a6b74bd |
279 | the C<where> block, so it can be accessed as C<$_[0]>. |
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280 | |
ad5ed80c |
281 | =item (2) |
282 | |
4a6b74bd |
283 | Note that C<ArrayRef[]> will not work. Moose will not parse this as a |
284 | container type, and instead you will have a new type named |
285 | "ArrayRef[]", which doesn't make any sense. |
286 | |
287 | =item (3) |
288 | |
289 | The C<BUILD> method is actually called by C<< Moose::Object->BUILDALL |
290 | >>, which is called by C<< Moose::Object->new >>. The C<BUILDALL> |
291 | method climbs the object inheritance graph and calls any C<BUILD> |
292 | methods it finds in the correct order. |
ad5ed80c |
293 | |
172e0738 |
294 | =back |
295 | |
8c3d5c88 |
296 | =head1 AUTHORS |
471c4f09 |
297 | |
298 | Stevan Little E<lt>stevan@iinteractive.comE<gt> |
299 | |
8c3d5c88 |
300 | Dave Rolsky E<lt>autarch@urth.orgE<gt> |
301 | |
471c4f09 |
302 | =head1 COPYRIGHT AND LICENSE |
303 | |
7e0492d3 |
304 | Copyright 2006-2010 by Infinity Interactive, Inc. |
471c4f09 |
305 | |
306 | L<http://www.iinteractive.com> |
307 | |
308 | This library is free software; you can redistribute it and/or modify |
309 | it under the same terms as Perl itself. |
310 | |
c79239a2 |
311 | =begin testing |
312 | |
313 | { |
314 | package Company; |
315 | |
316 | sub get_employee_count { scalar @{(shift)->employees} } |
317 | } |
318 | |
319 | use Scalar::Util 'isweak'; |
320 | |
321 | my $ii; |
322 | lives_ok { |
323 | $ii = Company->new( |
324 | { |
325 | name => 'Infinity Interactive', |
326 | address => Address->new( |
327 | street => '565 Plandome Rd., Suite 307', |
328 | city => 'Manhasset', |
329 | state => 'NY', |
330 | zip_code => '11030' |
331 | ), |
332 | employees => [ |
333 | Employee->new( |
334 | first_name => 'Jeremy', |
335 | last_name => 'Shao', |
336 | title => 'President / Senior Consultant', |
337 | address => |
338 | Address->new( city => 'Manhasset', state => 'NY' ) |
339 | ), |
340 | Employee->new( |
341 | first_name => 'Tommy', |
342 | last_name => 'Lee', |
343 | title => 'Vice President / Senior Developer', |
344 | address => |
345 | Address->new( city => 'New York', state => 'NY' ) |
346 | ), |
347 | Employee->new( |
348 | first_name => 'Stevan', |
349 | middle_initial => 'C', |
350 | last_name => 'Little', |
351 | title => 'Senior Developer', |
352 | address => |
353 | Address->new( city => 'Madison', state => 'CT' ) |
354 | ), |
355 | ] |
356 | } |
357 | ); |
358 | } |
359 | '... created the entire company successfully'; |
360 | isa_ok( $ii, 'Company' ); |
361 | |
362 | is( $ii->name, 'Infinity Interactive', |
363 | '... got the right name for the company' ); |
364 | |
365 | isa_ok( $ii->address, 'Address' ); |
366 | is( $ii->address->street, '565 Plandome Rd., Suite 307', |
367 | '... got the right street address' ); |
368 | is( $ii->address->city, 'Manhasset', '... got the right city' ); |
369 | is( $ii->address->state, 'NY', '... got the right state' ); |
370 | is( $ii->address->zip_code, 11030, '... got the zip code' ); |
371 | |
372 | is( $ii->get_employee_count, 3, '... got the right employee count' ); |
373 | |
374 | # employee #1 |
375 | |
376 | isa_ok( $ii->employees->[0], 'Employee' ); |
377 | isa_ok( $ii->employees->[0], 'Person' ); |
378 | |
379 | is( $ii->employees->[0]->first_name, 'Jeremy', |
380 | '... got the right first name' ); |
381 | is( $ii->employees->[0]->last_name, 'Shao', '... got the right last name' ); |
382 | ok( !$ii->employees->[0]->has_middle_initial, '... no middle initial' ); |
383 | is( $ii->employees->[0]->middle_initial, undef, |
384 | '... got the right middle initial value' ); |
385 | is( $ii->employees->[0]->full_name, |
386 | 'Jeremy Shao, President / Senior Consultant', |
387 | '... got the right full name' ); |
388 | is( $ii->employees->[0]->title, 'President / Senior Consultant', |
389 | '... got the right title' ); |
390 | is( $ii->employees->[0]->employer, $ii, '... got the right company' ); |
391 | ok( isweak( $ii->employees->[0]->{employer} ), |
392 | '... the company is a weak-ref' ); |
393 | |
394 | isa_ok( $ii->employees->[0]->address, 'Address' ); |
395 | is( $ii->employees->[0]->address->city, 'Manhasset', |
396 | '... got the right city' ); |
397 | is( $ii->employees->[0]->address->state, 'NY', '... got the right state' ); |
398 | |
399 | # employee #2 |
400 | |
401 | isa_ok( $ii->employees->[1], 'Employee' ); |
402 | isa_ok( $ii->employees->[1], 'Person' ); |
403 | |
404 | is( $ii->employees->[1]->first_name, 'Tommy', |
405 | '... got the right first name' ); |
406 | is( $ii->employees->[1]->last_name, 'Lee', '... got the right last name' ); |
407 | ok( !$ii->employees->[1]->has_middle_initial, '... no middle initial' ); |
408 | is( $ii->employees->[1]->middle_initial, undef, |
409 | '... got the right middle initial value' ); |
410 | is( $ii->employees->[1]->full_name, |
411 | 'Tommy Lee, Vice President / Senior Developer', |
412 | '... got the right full name' ); |
413 | is( $ii->employees->[1]->title, 'Vice President / Senior Developer', |
414 | '... got the right title' ); |
415 | is( $ii->employees->[1]->employer, $ii, '... got the right company' ); |
416 | ok( isweak( $ii->employees->[1]->{employer} ), |
417 | '... the company is a weak-ref' ); |
418 | |
419 | isa_ok( $ii->employees->[1]->address, 'Address' ); |
420 | is( $ii->employees->[1]->address->city, 'New York', |
421 | '... got the right city' ); |
422 | is( $ii->employees->[1]->address->state, 'NY', '... got the right state' ); |
423 | |
424 | # employee #3 |
425 | |
426 | isa_ok( $ii->employees->[2], 'Employee' ); |
427 | isa_ok( $ii->employees->[2], 'Person' ); |
428 | |
429 | is( $ii->employees->[2]->first_name, 'Stevan', |
430 | '... got the right first name' ); |
431 | is( $ii->employees->[2]->last_name, 'Little', '... got the right last name' ); |
432 | ok( $ii->employees->[2]->has_middle_initial, '... got middle initial' ); |
433 | is( $ii->employees->[2]->middle_initial, 'C', |
434 | '... got the right middle initial value' ); |
435 | is( $ii->employees->[2]->full_name, 'Stevan C. Little, Senior Developer', |
436 | '... got the right full name' ); |
437 | is( $ii->employees->[2]->title, 'Senior Developer', |
438 | '... got the right title' ); |
439 | is( $ii->employees->[2]->employer, $ii, '... got the right company' ); |
440 | ok( isweak( $ii->employees->[2]->{employer} ), |
441 | '... the company is a weak-ref' ); |
442 | |
443 | isa_ok( $ii->employees->[2]->address, 'Address' ); |
444 | is( $ii->employees->[2]->address->city, 'Madison', '... got the right city' ); |
445 | is( $ii->employees->[2]->address->state, 'CT', '... got the right state' ); |
446 | |
447 | # create new company |
448 | |
449 | my $new_company |
450 | = Company->new( name => 'Infinity Interactive International' ); |
451 | isa_ok( $new_company, 'Company' ); |
452 | |
453 | my $ii_employees = $ii->employees; |
454 | foreach my $employee (@$ii_employees) { |
455 | is( $employee->employer, $ii, '... has the ii company' ); |
456 | } |
457 | |
458 | $new_company->employees($ii_employees); |
459 | |
460 | foreach my $employee ( @{ $new_company->employees } ) { |
461 | is( $employee->employer, $new_company, |
462 | '... has the different company now' ); |
463 | } |
464 | |
465 | ## check some error conditions for the subtypes |
466 | |
467 | dies_ok { |
468 | Address->new( street => {} ),; |
469 | } |
470 | '... we die correctly with bad args'; |
471 | |
472 | dies_ok { |
473 | Address->new( city => {} ),; |
474 | } |
475 | '... we die correctly with bad args'; |
476 | |
477 | dies_ok { |
478 | Address->new( state => 'British Columbia' ),; |
479 | } |
480 | '... we die correctly with bad args'; |
481 | |
482 | lives_ok { |
483 | Address->new( state => 'Connecticut' ),; |
484 | } |
485 | '... we live correctly with good args'; |
486 | |
487 | dies_ok { |
488 | Address->new( zip_code => 'AF5J6$' ),; |
489 | } |
490 | '... we die correctly with bad args'; |
491 | |
492 | lives_ok { |
493 | Address->new( zip_code => '06443' ),; |
494 | } |
495 | '... we live correctly with good args'; |
496 | |
497 | dies_ok { |
498 | Company->new(),; |
499 | } |
500 | '... we die correctly without good args'; |
501 | |
502 | lives_ok { |
503 | Company->new( name => 'Foo' ),; |
504 | } |
505 | '... we live correctly without good args'; |
506 | |
507 | dies_ok { |
508 | Company->new( name => 'Foo', employees => [ Person->new ] ),; |
509 | } |
510 | '... we die correctly with good args'; |
511 | |
512 | lives_ok { |
513 | Company->new( name => 'Foo', employees => [] ),; |
514 | } |
515 | '... we live correctly with good args'; |
516 | |
517 | =end testing |
518 | |
e08c54f5 |
519 | =cut |