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 $baseUrl |
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| 27 | */ |
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| 28 | 25 | public function __construct($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 $data |
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| 39 | * |
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| 40 | * @return array |
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| 41 | */ |
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| 42 | 17 | public function collection($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 $data |
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| 58 | * |
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| 59 | * @return array |
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| 60 | */ |
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| 61 | 25 | public function item($resourceKey, array $data) |
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| 83 | |||
| 84 | /** |
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| 85 | * Serialize the paginator. |
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| 86 | * |
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| 87 | * @param PaginatorInterface $paginator |
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| 88 | * |
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| 89 | * @return array |
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| 90 | */ |
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| 91 | 3 | public function paginator(PaginatorInterface $paginator) |
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| 121 | |||
| 122 | /** |
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| 123 | * Serialize the meta. |
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| 124 | * |
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| 125 | * @param array $meta |
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| 126 | * |
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| 127 | * @return array |
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| 128 | */ |
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| 129 | 24 | public function meta(array $meta) |
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| 144 | |||
| 145 | /** |
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| 146 | * @return array |
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| 147 | */ |
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| 148 | 2 | public function null() |
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| 154 | |||
| 155 | /** |
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| 156 | * Serialize the included data. |
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| 157 | * |
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| 158 | * @param ResourceInterface $resource |
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| 159 | * @param array $data |
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| 160 | * |
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| 161 | * @return array |
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| 162 | */ |
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| 163 | 24 | public function includedData(ResourceInterface $resource, array $data) |
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| 189 | |||
| 190 | /** |
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| 191 | * Indicates if includes should be side-loaded. |
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| 192 | * |
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| 193 | * @return bool |
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| 194 | */ |
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| 195 | 25 | public function sideloadIncludes() |
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| 199 | |||
| 200 | /** |
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| 201 | * @param array $data |
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| 202 | * @param array $includedData |
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| 203 | * |
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| 204 | * @return array |
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| 205 | */ |
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| 206 | 24 | public function injectData($data, $includedData) |
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| 216 | |||
| 217 | /** |
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| 218 | * Hook to manipulate the final sideloaded includes. |
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| 219 | * The JSON API specification does not allow the root object to be included |
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| 220 | * into the sideloaded `included`-array. We have to make sure it is |
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| 221 | * filtered out, in case some object links to the root object in a |
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| 222 | * relationship. |
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| 223 | * |
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| 224 | * @param array $includedData |
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| 225 | * @param array $data |
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| 226 | * |
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| 227 | * @return array |
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| 228 | */ |
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| 229 | 24 | public function filterIncludes($includedData, $data) |
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| 246 | |||
| 247 | /** |
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| 248 | * Filter function to delete root objects from array. |
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| 249 | * |
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| 250 | * @param array $object |
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| 251 | * |
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| 252 | * @return bool |
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| 253 | */ |
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| 254 | 13 | protected function filterRootObject($object) |
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| 258 | |||
| 259 | /** |
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| 260 | * Set the root objects of the JSON API tree. |
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| 261 | * |
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| 262 | * @param array $objects |
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| 263 | */ |
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| 264 | protected function setRootObjects(array $objects = []) |
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| 270 | |||
| 271 | /** |
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| 272 | * Determines whether an object is a root object of the JSON API tree. |
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| 273 | * |
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| 274 | * @param array $object |
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| 275 | * |
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| 276 | * @return bool |
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| 277 | */ |
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| 278 | 13 | protected function isRootObject($object) |
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| 283 | |||
| 284 | /** |
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| 285 | * @param array $data |
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| 286 | * |
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| 287 | * @return bool |
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| 288 | */ |
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| 289 | 15 | protected function isCollection($data) |
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| 294 | |||
| 295 | /** |
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| 296 | * @param array $data |
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| 297 | * |
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| 298 | * @return bool |
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| 299 | */ |
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| 300 | 15 | protected function isNull($data) |
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| 304 | |||
| 305 | /** |
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| 306 | * @param array $data |
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| 307 | * |
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| 308 | * @return bool |
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| 309 | */ |
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| 310 | 14 | protected function isEmpty($data) |
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| 314 | |||
| 315 | /** |
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| 316 | * @param array $data |
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| 317 | * @param array $relationships |
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| 318 | * |
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| 319 | * @return array |
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| 320 | */ |
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| 321 | 15 | protected function fillRelationships($data, $relationships) |
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| 335 | |||
| 336 | /** |
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| 337 | * @param array $includedData |
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| 338 | * |
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| 339 | * @return array |
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| 340 | */ |
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| 341 | 24 | protected function parseRelationships($includedData) |
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| 353 | |||
| 354 | /** |
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| 355 | * @param array $data |
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| 356 | * |
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| 357 | * @return integer |
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| 358 | */ |
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| 359 | 25 | protected function getIdFromData(array $data) |
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| 368 | |||
| 369 | /** |
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| 370 | * Keep all sideloaded inclusion data on the top level. |
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| 371 | * |
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| 372 | * @param array $data |
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| 373 | * |
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| 374 | * @return array |
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| 375 | */ |
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| 376 | 24 | protected function pullOutNestedIncludedData(array $data) |
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| 400 | |||
| 401 | /** |
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| 402 | * Whether or not the serializer should include `links` for resource objects. |
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| 403 | * |
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| 404 | * @return bool |
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| 405 | */ |
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| 406 | 24 | protected function shouldIncludeLinks() |
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| 410 | |||
| 411 | /** |
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| 412 | * Check if the objects are part of a collection or not |
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| 413 | * |
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| 414 | * @param $includeObject |
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| 415 | * |
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| 416 | * @return array |
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| 417 | */ |
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| 418 | 13 | private function createIncludeObjects($includeObject) |
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| 430 | |||
| 431 | /** |
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| 432 | * Sets the RootObjects, either as collection or not. |
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| 433 | * |
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| 434 | * @param $data |
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| 435 | */ |
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| 436 | 13 | private function createRootObjects($data) |
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| 444 | |||
| 445 | |||
| 446 | /** |
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| 447 | * Loops over the relationships of the provided data and formats it |
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| 448 | * |
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| 449 | * @param $data |
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| 450 | * @param $relationship |
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| 451 | * @param $nestedDepth |
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| 452 | * |
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| 453 | * @return array |
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| 454 | */ |
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| 455 | 7 | private function fillRelationshipAsCollection($data, $relationship, $nestedDepth) |
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| 463 | |||
| 464 | |||
| 465 | /** |
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| 466 | * @param $data |
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| 467 | * @param $relationship |
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| 468 | * @param $key |
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| 469 | * |
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| 470 | * @return array |
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| 471 | */ |
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| 472 | 10 | private function FillRelationshipAsSingleResource($data, $relationship, $key) |
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| 488 | |||
| 489 | /** |
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| 490 | * @param $includeKey |
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| 491 | * @param $relationships |
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| 492 | * @param $includeObject |
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| 493 | * @param $key |
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| 494 | * |
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| 495 | * @return array |
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| 496 | */ |
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| 497 | 15 | private function buildRelationships($includeKey, $relationships, $includeObject, $key) |
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| 524 | |||
| 525 | /** |
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| 526 | * @param $includeKey |
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| 527 | * @param $relationships |
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| 528 | * |
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| 529 | * @return array |
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| 530 | */ |
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| 531 | 15 | private function addIncludekeyToRelationsIfNotSet($includeKey, $relationships) |
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| 540 | |||
| 541 | /** |
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| 542 | * @param $includeObject |
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| 543 | * @param $relationship |
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| 544 | * |
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| 545 | * @return array |
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| 546 | */ |
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| 547 | 7 | private function addIncludedDataToRelationship($includeObject, $relationship) |
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| 558 | } |
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| 559 |