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 |
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| 18 | class JsonApiSerializer extends ArraySerializer |
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| 19 | { |
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| 20 | protected $baseUrl; |
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| 21 | protected $rootObjects; |
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| 22 | |||
| 23 | /** |
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| 24 | * JsonApiSerializer constructor. |
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| 25 | * |
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| 26 | * @param string $baseUrl |
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| 27 | */ |
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| 28 | 29 | public function __construct($baseUrl = null) |
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| 33 | |||
| 34 | /** |
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| 35 | * Serialize a collection. |
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| 36 | * |
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| 37 | * @param string $resourceKey |
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| 38 | * @param array $data |
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| 39 | * |
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| 40 | * @return array |
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| 41 | */ |
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| 42 | 19 | public function collection($resourceKey, array $data) |
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| 52 | |||
| 53 | /** |
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| 54 | * Serialize an item. |
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| 55 | * |
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| 56 | * @param string $resourceKey |
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| 57 | * @param array $data |
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| 58 | * |
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| 59 | * @return array |
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| 60 | */ |
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| 61 | 29 | public function item($resourceKey, array $data) |
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| 91 | |||
| 92 | /** |
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| 93 | * Serialize the paginator. |
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| 94 | * |
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| 95 | * @param PaginatorInterface $paginator |
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| 96 | * |
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| 97 | * @return array |
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| 98 | */ |
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| 99 | 3 | public function paginator(PaginatorInterface $paginator) |
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| 129 | |||
| 130 | /** |
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| 131 | * Serialize the meta. |
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| 132 | * |
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| 133 | * @param array $meta |
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| 134 | * |
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| 135 | * @return array |
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| 136 | */ |
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| 137 | 28 | public function meta(array $meta) |
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| 152 | |||
| 153 | /** |
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| 154 | * @return array |
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| 155 | */ |
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| 156 | 2 | public function null() |
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| 162 | |||
| 163 | /** |
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| 164 | * Serialize the included data. |
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| 165 | * |
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| 166 | * @param ResourceInterface $resource |
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| 167 | * @param array $data |
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| 168 | * |
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| 169 | * @return array |
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| 170 | */ |
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| 171 | 28 | public function includedData(ResourceInterface $resource, array $data) |
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| 197 | |||
| 198 | /** |
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| 199 | * Indicates if includes should be side-loaded. |
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| 200 | * |
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| 201 | * @return bool |
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| 202 | */ |
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| 203 | 29 | public function sideloadIncludes() |
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| 204 | { |
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| 205 | 29 | return true; |
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| 206 | } |
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| 207 | |||
| 208 | /** |
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| 209 | * @param array $data |
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| 210 | * @param array $includedData |
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| 211 | * |
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| 212 | * @return array |
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| 213 | */ |
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| 214 | 28 | public function injectData($data, $includedData) |
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| 224 | |||
| 225 | /** |
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| 226 | * Hook to manipulate the final sideloaded includes. |
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| 227 | * The JSON API specification does not allow the root object to be included |
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| 228 | * into the sideloaded `included`-array. We have to make sure it is |
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| 229 | * filtered out, in case some object links to the root object in a |
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| 230 | * relationship. |
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| 231 | * |
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| 232 | * @param array $includedData |
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| 233 | * @param array $data |
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| 234 | * |
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| 235 | * @return array |
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| 236 | */ |
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| 237 | 28 | public function filterIncludes($includedData, $data) |
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| 254 | |||
| 255 | /** |
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| 256 | * Filter function to delete root objects from array. |
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| 257 | * |
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| 258 | * @param array $object |
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| 259 | * |
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| 260 | * @return bool |
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| 261 | */ |
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| 262 | 15 | protected function filterRootObject($object) |
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| 266 | |||
| 267 | /** |
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| 268 | * Set the root objects of the JSON API tree. |
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| 269 | * |
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| 270 | * @param array $objects |
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| 271 | */ |
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| 272 | protected function setRootObjects(array $objects = []) |
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| 278 | |||
| 279 | /** |
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| 280 | * Determines whether an object is a root object of the JSON API tree. |
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| 281 | * |
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| 282 | * @param array $object |
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| 283 | * |
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| 284 | * @return bool |
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| 285 | */ |
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| 286 | 15 | protected function isRootObject($object) |
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| 291 | |||
| 292 | /** |
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| 293 | * @param array $data |
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| 294 | * |
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| 295 | * @return bool |
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| 296 | */ |
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| 297 | 17 | protected function isCollection($data) |
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| 302 | |||
| 303 | /** |
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| 304 | * @param array $data |
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| 305 | * |
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| 306 | * @return bool |
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| 307 | */ |
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| 308 | 17 | protected function isNull($data) |
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| 312 | |||
| 313 | /** |
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| 314 | * @param array $data |
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| 315 | * |
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| 316 | * @return bool |
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| 317 | */ |
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| 318 | 16 | protected function isEmpty($data) |
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| 322 | |||
| 323 | /** |
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| 324 | * @param array $data |
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| 325 | * @param array $relationships |
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| 326 | * |
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| 327 | * @return array |
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| 328 | */ |
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| 329 | 17 | protected function fillRelationships($data, $relationships) |
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| 343 | |||
| 344 | /** |
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| 345 | * @param array $includedData |
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| 346 | * |
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| 347 | * @return array |
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| 348 | */ |
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| 349 | 28 | protected function parseRelationships($includedData) |
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| 361 | |||
| 362 | /** |
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| 363 | * @param array $data |
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| 364 | * |
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| 365 | * @return integer |
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| 366 | */ |
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| 367 | 29 | protected function getIdFromData(array $data) |
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| 376 | |||
| 377 | /** |
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| 378 | * Keep all sideloaded inclusion data on the top level. |
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| 379 | * |
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| 380 | * @param array $data |
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| 381 | * |
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| 382 | * @return array |
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| 383 | */ |
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| 384 | 28 | protected function pullOutNestedIncludedData(array $data) |
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| 408 | |||
| 409 | /** |
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| 410 | * Whether or not the serializer should include `links` for resource objects. |
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| 411 | * |
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| 412 | * @return bool |
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| 413 | */ |
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| 414 | 28 | protected function shouldIncludeLinks() |
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| 418 | |||
| 419 | /** |
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| 420 | * Check if the objects are part of a collection or not |
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| 421 | * |
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| 422 | * @param $includeObject |
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| 423 | * |
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| 424 | * @return array |
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| 425 | */ |
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| 426 | 15 | private function createIncludeObjects($includeObject) |
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| 438 | |||
| 439 | /** |
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| 440 | * Sets the RootObjects, either as collection or not. |
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| 441 | * |
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| 442 | * @param $data |
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| 443 | */ |
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| 444 | 15 | private function createRootObjects($data) |
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| 452 | |||
| 453 | |||
| 454 | /** |
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| 455 | * Loops over the relationships of the provided data and formats it |
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| 456 | * |
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| 457 | * @param $data |
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| 458 | * @param $relationship |
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| 459 | * @param $key |
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| 460 | * |
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| 461 | * @return array |
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| 462 | */ |
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| 463 | 9 | private function fillRelationshipAsCollection($data, $relationship, $key) |
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| 480 | |||
| 481 | |||
| 482 | /** |
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| 483 | * @param $data |
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| 484 | * @param $relationship |
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| 485 | * @param $key |
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| 486 | * |
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| 487 | * @return array |
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| 488 | */ |
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| 489 | 10 | private function fillRelationshipAsSingleResource($data, $relationship, $key) |
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| 505 | |||
| 506 | /** |
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| 507 | * @param $includeKey |
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| 508 | * @param $relationships |
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| 509 | * @param $includeObject |
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| 510 | * @param $key |
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| 511 | * |
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| 512 | * @return array |
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| 513 | */ |
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| 514 | 17 | private function buildRelationships($includeKey, $relationships, $includeObject, $key) |
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| 541 | |||
| 542 | /** |
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| 543 | * @param $includeKey |
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| 544 | * @param $relationships |
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| 545 | * |
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| 546 | * @return array |
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| 547 | */ |
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| 548 | 17 | private function addIncludekeyToRelationsIfNotSet($includeKey, $relationships) |
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| 557 | |||
| 558 | /** |
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| 559 | * @param $includeObject |
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| 560 | * @param $relationship |
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| 561 | * |
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| 562 | * @return array |
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| 563 | */ |
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| 564 | 8 | private function addIncludedDataToRelationship($includeObject, $relationship) |
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| 575 | } |
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| 576 |