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