Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like JsonApiSerializer often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use JsonApiSerializer, and based on these observations, apply Extract Interface, too.
1 | <?php |
||
18 | class JsonApiSerializer extends ArraySerializer |
||
19 | { |
||
20 | protected $baseUrl; |
||
21 | protected $rootObjects; |
||
22 | |||
23 | 27 | public function __construct($baseUrl = null) |
|
24 | { |
||
25 | 27 | $this->baseUrl = $baseUrl; |
|
26 | 27 | $this->rootObjects = []; |
|
27 | 27 | } |
|
28 | |||
29 | /** |
||
30 | * Serialize a collection. |
||
31 | * |
||
32 | * @param string $resourceKey |
||
33 | * @param array $data |
||
34 | * |
||
35 | * @return array |
||
36 | */ |
||
37 | 19 | public function collection($resourceKey, array $data) |
|
38 | { |
||
39 | 19 | $resources = []; |
|
40 | |||
41 | 19 | foreach ($data as $resource) { |
|
42 | 18 | $resources[] = $this->item($resourceKey, $resource)['data']; |
|
43 | 19 | } |
|
44 | |||
45 | 19 | return ['data' => $resources]; |
|
46 | } |
||
47 | |||
48 | /** |
||
49 | * Serialize an item. |
||
50 | * |
||
51 | * @param string $resourceKey |
||
52 | * @param array $data |
||
53 | * |
||
54 | * @return array |
||
55 | */ |
||
56 | 27 | public function item($resourceKey, array $data) |
|
78 | |||
79 | /** |
||
80 | * Serialize the paginator. |
||
81 | * |
||
82 | * @param PaginatorInterface $paginator |
||
83 | * |
||
84 | * @return array |
||
85 | */ |
||
86 | 3 | public function paginator(PaginatorInterface $paginator) |
|
116 | |||
117 | /** |
||
118 | * Serialize the meta. |
||
119 | * |
||
120 | * @param array $meta |
||
121 | * |
||
122 | * @return array |
||
123 | */ |
||
124 | 26 | public function meta(array $meta) |
|
139 | |||
140 | /** |
||
141 | * @return array |
||
142 | */ |
||
143 | 2 | public function null() |
|
149 | |||
150 | /** |
||
151 | * Serialize the included data. |
||
152 | * |
||
153 | * @param ResourceInterface $resource |
||
154 | * @param array $data |
||
155 | * |
||
156 | * @return array |
||
157 | */ |
||
158 | 26 | public function includedData(ResourceInterface $resource, array $data) |
|
187 | |||
188 | /** |
||
189 | * Indicates if includes should be side-loaded. |
||
190 | * |
||
191 | * @return bool |
||
192 | */ |
||
193 | 27 | public function sideloadIncludes() |
|
197 | |||
198 | /** |
||
199 | * @param array $data |
||
200 | * @param array $includedData |
||
201 | * |
||
202 | * @return array |
||
203 | */ |
||
204 | 26 | public function injectData($data, $includedData) |
|
214 | |||
215 | /** |
||
216 | * Hook to manipulate the final sideloaded includes. |
||
217 | * |
||
218 | * The JSON API specification does not allow the root object to be included |
||
219 | * into the sideloaded `included`-array. We have to make sure it is |
||
220 | * filtered out, in case some object links to the root object in a |
||
221 | * relationship. |
||
222 | * |
||
223 | * @param array $includedData |
||
224 | * @param array $data |
||
225 | * |
||
226 | * @return array |
||
227 | */ |
||
228 | 26 | public function filterIncludes($includedData, $data) |
|
248 | |||
249 | /** |
||
250 | * Filter function to delete root objects from array. |
||
251 | * |
||
252 | * @param array $object |
||
253 | * |
||
254 | * @return bool |
||
255 | */ |
||
256 | 15 | protected function filterRootObject($object) |
|
260 | |||
261 | /** |
||
262 | * Set the root objects of the JSON API tree. |
||
263 | * |
||
264 | * @param array $objects |
||
265 | */ |
||
266 | protected function setRootObjects(array $objects = []) |
||
272 | |||
273 | /** |
||
274 | * Determines whether an object is a root object of the JSON API tree. |
||
275 | * |
||
276 | * @param array $object |
||
277 | * |
||
278 | * @return bool |
||
279 | */ |
||
280 | 15 | protected function isRootObject($object) |
|
285 | |||
286 | /** |
||
287 | * @param array $data |
||
288 | * |
||
289 | * @return bool |
||
290 | */ |
||
291 | 17 | protected function isCollection($data) |
|
296 | |||
297 | /** |
||
298 | * @param array $data |
||
299 | * |
||
300 | * @return bool |
||
301 | */ |
||
302 | 17 | protected function isNull($data) |
|
306 | |||
307 | /** |
||
308 | * @param array $data |
||
309 | * |
||
310 | * @return bool |
||
311 | */ |
||
312 | 16 | protected function isEmpty($data) |
|
316 | |||
317 | /** |
||
318 | * @param array $data |
||
319 | * @param array $relationships |
||
320 | * |
||
321 | * @return mixed |
||
322 | */ |
||
323 | 17 | protected function fillRelationships($data, $relationships) |
|
357 | |||
358 | /** |
||
359 | * @param array $includedData |
||
360 | * |
||
361 | * @return array |
||
362 | */ |
||
363 | 26 | protected function parseRelationships($includedData) |
|
403 | |||
404 | /** |
||
405 | * @param array $data |
||
406 | * |
||
407 | * @return mixed |
||
408 | */ |
||
409 | 27 | protected function getIdFromData(array $data) |
|
418 | |||
419 | /** |
||
420 | * Keep all sideloaded inclusion data on the top level. |
||
421 | * |
||
422 | * @param array $data |
||
423 | * |
||
424 | * @return array |
||
425 | */ |
||
426 | 26 | protected function pullOutNestedIncludedData(array $data) |
|
450 | |||
451 | /** |
||
452 | * Whether or not the serializer should include `links` for resource objects. |
||
453 | * |
||
454 | * @return bool |
||
455 | */ |
||
456 | 26 | protected function shouldIncludeLinks() |
|
460 | } |
||
461 |