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 $baseUrl |
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27 | */ |
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28 | 27 | public function __construct($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 $data |
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58 | * |
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59 | * @return array |
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60 | */ |
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61 | 27 | public function item($resourceKey, array $data) |
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89 | |||
90 | /** |
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91 | * Serialize the paginator. |
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92 | * |
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93 | * @param PaginatorInterface $paginator |
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94 | * |
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95 | * @return array |
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96 | */ |
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97 | 3 | public function paginator(PaginatorInterface $paginator) |
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127 | |||
128 | /** |
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129 | * Serialize the meta. |
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130 | * |
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131 | * @param array $meta |
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132 | * |
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133 | * @return array |
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134 | */ |
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135 | 26 | public function meta(array $meta) |
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150 | |||
151 | /** |
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152 | * @return array |
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153 | */ |
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154 | 2 | public function null() |
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160 | |||
161 | /** |
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162 | * Serialize the included data. |
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163 | * |
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164 | * @param ResourceInterface $resource |
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165 | * @param array $data |
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166 | * |
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167 | * @return array |
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168 | */ |
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169 | 26 | public function includedData(ResourceInterface $resource, array $data) |
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195 | |||
196 | /** |
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197 | * Indicates if includes should be side-loaded. |
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198 | * |
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199 | * @return bool |
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200 | */ |
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201 | 27 | public function sideloadIncludes() |
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205 | |||
206 | /** |
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207 | * @param array $data |
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208 | * @param array $includedData |
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209 | * |
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210 | * @return array |
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211 | */ |
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212 | 26 | public function injectData($data, $includedData) |
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222 | |||
223 | /** |
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224 | * Hook to manipulate the final sideloaded includes. |
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225 | * The JSON API specification does not allow the root object to be included |
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226 | * into the sideloaded `included`-array. We have to make sure it is |
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227 | * filtered out, in case some object links to the root object in a |
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228 | * relationship. |
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229 | * |
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230 | * @param array $includedData |
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231 | * @param array $data |
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232 | * |
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233 | * @return array |
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234 | */ |
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235 | 26 | public function filterIncludes($includedData, $data) |
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252 | |||
253 | /** |
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254 | * Filter function to delete root objects from array. |
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255 | * |
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256 | * @param array $object |
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257 | * |
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258 | * @return bool |
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259 | */ |
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260 | 13 | protected function filterRootObject($object) |
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264 | |||
265 | /** |
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266 | * Set the root objects of the JSON API tree. |
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267 | * |
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268 | * @param array $objects |
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269 | */ |
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270 | protected function setRootObjects(array $objects = []) |
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276 | |||
277 | /** |
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278 | * Determines whether an object is a root object of the JSON API tree. |
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279 | * |
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280 | * @param array $object |
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281 | * |
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282 | * @return bool |
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283 | */ |
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284 | 13 | protected function isRootObject($object) |
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289 | |||
290 | /** |
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291 | * @param array $data |
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292 | * |
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293 | * @return bool |
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294 | */ |
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295 | 15 | protected function isCollection($data) |
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300 | |||
301 | /** |
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302 | * @param array $data |
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303 | * |
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304 | * @return bool |
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305 | */ |
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306 | 15 | protected function isNull($data) |
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310 | |||
311 | /** |
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312 | * @param array $data |
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313 | * |
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314 | * @return bool |
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315 | */ |
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316 | 14 | protected function isEmpty($data) |
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320 | |||
321 | /** |
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322 | * @param array $data |
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323 | * @param array $relationships |
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324 | * |
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325 | * @return array |
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326 | */ |
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327 | 15 | protected function fillRelationships($data, $relationships) |
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341 | |||
342 | /** |
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343 | * @param array $includedData |
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344 | * |
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345 | * @return array |
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346 | */ |
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347 | 26 | protected function parseRelationships($includedData) |
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359 | |||
360 | /** |
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361 | * @param array $data |
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362 | * |
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363 | * @return integer |
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364 | */ |
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365 | 27 | protected function getIdFromData(array $data) |
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374 | |||
375 | /** |
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376 | * Keep all sideloaded inclusion data on the top level. |
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377 | * |
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378 | * @param array $data |
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379 | * |
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380 | * @return array |
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381 | */ |
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382 | 26 | protected function pullOutNestedIncludedData(array $data) |
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406 | |||
407 | /** |
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408 | * Whether or not the serializer should include `links` for resource objects. |
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409 | * |
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410 | * @return bool |
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411 | */ |
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412 | 26 | protected function shouldIncludeLinks() |
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416 | |||
417 | /** |
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418 | * Check if the objects are part of a collection or not |
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419 | * |
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420 | * @param $includeObject |
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421 | * |
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422 | * @return array |
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423 | */ |
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424 | 13 | private function createIncludeObjects($includeObject) |
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436 | |||
437 | /** |
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438 | * Sets the RootObjects, either as collection or not. |
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439 | * |
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440 | * @param $data |
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441 | */ |
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442 | 13 | private function createRootObjects($data) |
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450 | |||
451 | |||
452 | /** |
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453 | * Loops over the relationships of the provided data and formats it |
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454 | * |
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455 | * @param $data |
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456 | * @param $relationship |
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457 | * @param $nestedDepth |
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458 | * |
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459 | * @return array |
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460 | */ |
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461 | 7 | private function fillRelationshipAsCollection($data, $relationship, $nestedDepth) |
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469 | |||
470 | |||
471 | /** |
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472 | * @param $data |
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473 | * @param $relationship |
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474 | * @param $key |
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475 | * |
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476 | * @return array |
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477 | */ |
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478 | 10 | private function FillRelationshipAsSingleResource($data, $relationship, $key) |
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494 | |||
495 | /** |
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496 | * @param $includeKey |
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497 | * @param $relationships |
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498 | * @param $includeObject |
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499 | * @param $key |
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500 | * |
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501 | * @return array |
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502 | */ |
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503 | 15 | private function buildRelationships($includeKey, $relationships, $includeObject, $key) |
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530 | |||
531 | /** |
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532 | * @param $includeKey |
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533 | * @param $relationships |
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534 | * |
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535 | * @return array |
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536 | */ |
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537 | 15 | private function addIncludekeyToRelationsIfNotSet($includeKey, $relationships) |
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546 | |||
547 | /** |
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548 | * @param $includeObject |
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549 | * @param $relationship |
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550 | * |
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551 | * @return array |
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552 | */ |
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553 | 7 | private function addIncludedDataToRelationship($includeObject, $relationship) |
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564 | } |
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565 |