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 | /** @var string|null */ |
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| 21 | protected $baseUrl; |
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| 22 | |||
| 23 | /** @var array */ |
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| 24 | protected $rootObjects; |
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| 25 | |||
| 26 | 19 | public function __construct(? string $baseUrl = null) |
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| 31 | |||
| 32 | /** |
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| 33 | * Serialize a collection. |
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| 34 | * |
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| 35 | * @param string $resourceKey |
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| 36 | * @param array $data |
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| 37 | * |
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| 38 | * @return array |
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| 39 | */ |
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| 40 | 13 | public function collection($resourceKey, array $data) : array |
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| 50 | |||
| 51 | /** |
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| 52 | * Serialize an item. |
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| 53 | * |
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| 54 | * @param string $resourceKey |
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| 55 | * @param array $data |
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| 56 | * |
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| 57 | * @return array |
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| 58 | */ |
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| 59 | 12 | public function serializeItem($resourceKey, array $data) : array |
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| 99 | |||
| 100 | /** |
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| 101 | * Serialize the paginator. |
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| 102 | * |
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| 103 | * @param PaginatorInterface $paginator |
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| 104 | * |
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| 105 | * @return array |
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| 106 | */ |
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| 107 | public function serializePaginator(PaginatorInterface $paginator) : array |
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| 137 | |||
| 138 | 19 | public function meta(array $meta) : array |
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| 153 | |||
| 154 | 1 | public function null() : array |
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| 160 | |||
| 161 | 19 | public function includedData(ResourceInterface $resource, array $data) : array |
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| 178 | |||
| 179 | /** |
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| 180 | * Indicates if includes should be side-loaded. |
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| 181 | * |
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| 182 | * @return bool |
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| 183 | */ |
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| 184 | 19 | public function sideloadIncludes() |
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| 188 | |||
| 189 | /** |
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| 190 | * @param array $data |
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| 191 | * @param array $includedData |
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| 192 | * |
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| 193 | * @return array |
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| 194 | */ |
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| 195 | 19 | public function injectData($data, $includedData) : array |
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| 205 | |||
| 206 | /** |
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| 207 | * Hook to manipulate the final sideloaded includes. |
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| 208 | * The JSON API specification does not allow the root object to be included |
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| 209 | * into the sideloaded `included`-array. We have to make sure it is |
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| 210 | * filtered out, in case some object links to the root object in a |
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| 211 | * relationship. |
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| 212 | * |
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| 213 | * @param array $includedData |
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| 214 | * @param array $data |
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| 215 | * |
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| 216 | * @return array |
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| 217 | */ |
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| 218 | 19 | public function filterIncludes($includedData, $data) : array |
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| 235 | |||
| 236 | /** |
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| 237 | * Get the mandatory fields for the serializer |
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| 238 | * |
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| 239 | * @return array |
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| 240 | */ |
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| 241 | 2 | public function getMandatoryFields() : array |
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| 245 | |||
| 246 | /** |
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| 247 | * Filter function to delete root objects from array. |
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| 248 | * |
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| 249 | * @param array $object |
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| 250 | * |
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| 251 | * @return bool |
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| 252 | */ |
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| 253 | 3 | protected function filterRootObject($object) : bool |
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| 257 | |||
| 258 | /** |
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| 259 | * Set the root objects of the JSON API tree. |
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| 260 | * |
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| 261 | * @param array $objects |
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| 262 | */ |
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| 263 | 3 | protected function setRootObjects(array $objects = []) : void |
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| 269 | |||
| 270 | /** |
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| 271 | * Determines whether an object is a root object of the JSON API tree. |
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| 272 | * |
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| 273 | * @param array $object |
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| 274 | * |
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| 275 | * @return bool |
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| 276 | */ |
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| 277 | 3 | protected function isRootObject($object) : bool |
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| 282 | |||
| 283 | /** |
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| 284 | * @param array|null $data |
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| 285 | * |
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| 286 | * @return bool |
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| 287 | */ |
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| 288 | 11 | protected function isCollection($data) : bool |
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| 297 | |||
| 298 | /** |
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| 299 | * @param array|null $data |
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| 300 | * |
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| 301 | * @return bool |
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| 302 | */ |
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| 303 | 7 | protected function isNull($data) : bool |
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| 311 | |||
| 312 | /** |
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| 313 | * @param array|null $data |
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| 314 | * |
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| 315 | * @return bool |
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| 316 | */ |
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| 317 | 6 | protected function isEmpty($data) : bool |
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| 325 | |||
| 326 | /** |
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| 327 | * @param array $data |
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| 328 | * @param array $relationships |
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| 329 | * |
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| 330 | * @return array |
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| 331 | */ |
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| 332 | 7 | protected function fillRelationships($data, $relationships) : array |
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| 346 | |||
| 347 | /** |
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| 348 | * @param array $includedData |
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| 349 | * |
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| 350 | * @return array |
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| 351 | */ |
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| 352 | 19 | protected function parseRelationships($includedData) : array |
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| 367 | |||
| 368 | /** |
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| 369 | * @param array $data |
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| 370 | * |
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| 371 | * @return integer |
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| 372 | */ |
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| 373 | 12 | protected function getIdFromData(array $data) : int |
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| 382 | |||
| 383 | /** |
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| 384 | * Keep all sideloaded inclusion data on the top level. |
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| 385 | * |
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| 386 | * @param array $data |
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| 387 | * |
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| 388 | * @return array |
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| 389 | */ |
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| 390 | 19 | protected function pullOutNestedIncludedData(array $data) : array |
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| 405 | |||
| 406 | /** |
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| 407 | * Whether or not the serializer should include `links` for resource objects. |
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| 408 | * |
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| 409 | * @return bool |
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| 410 | */ |
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| 411 | 18 | protected function shouldIncludeLinks() : bool |
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| 415 | |||
| 416 | /** |
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| 417 | * Check if the objects are part of a collection or not |
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| 418 | * |
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| 419 | * @param array $includeObject |
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| 420 | * |
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| 421 | * @return array |
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| 422 | */ |
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| 423 | 5 | private function createIncludeObjects($includeObject) : array |
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| 435 | |||
| 436 | /** |
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| 437 | * Sets the RootObjects, either as collection or not. |
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| 438 | * |
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| 439 | * @param array $data |
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| 440 | */ |
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| 441 | 3 | private function createRootObjects(array $data) : void |
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| 449 | |||
| 450 | 3 | private function fillRelationshipAsCollection($data, $relationship, $key) : array |
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| 458 | |||
| 459 | 4 | private function fillRelationshipAsSingleResource($data, $relationship, $key) : array |
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| 465 | |||
| 466 | 7 | private function buildRelationships(string $includeKey, array $relationships, array $includeObject, string $key) : array |
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| 492 | |||
| 493 | 7 | private function addIncludeKeyToRelationsIfNotSet(string $includeKey, array $relationships) : array |
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| 502 | |||
| 503 | /** |
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| 504 | * @param array $includeObject |
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| 505 | * @param array $relationship |
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| 506 | * |
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| 507 | * @return array |
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| 508 | */ |
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| 509 | 5 | private function addIncludedDataToRelationship(array $includeObject, array $relationship) : array |
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| 520 | |||
| 521 | 18 | public function injectAvailableIncludeData($data, $availableIncludes) : array |
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| 542 | |||
| 543 | 5 | private function addRelationshipLinks(array $resource, string $relationshipKey) : array |
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| 561 | |||
| 562 | 5 | private function serializeIncludedObjectsWithCacheKey(array $includeObjects, array $linkedIds, array $serializedData) : array |
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| 575 | } |
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| 576 |
Adding an explicit array definition is generally preferable to implicit array definition as it guarantees a stable state of the code.
Let’s take a look at an example:
As you can see in this example, the array
$myArrayis initialized the first time when the foreach loop is entered. You can also see that the value of thebarkey is only written conditionally; thus, its value might result from a previous iteration.This might or might not be intended. To make your intention clear, your code more readible and to avoid accidental bugs, we recommend to add an explicit initialization $myArray = array() either outside or inside the foreach loop.