Complex classes like Serializer 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 Serializer, and based on these observations, apply Extract Interface, too.
1 | <?php |
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18 | class Serializer extends Component |
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19 | { |
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20 | /** |
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21 | * @var string the name of the query parameter containing the information about which fields should be returned |
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22 | * for a [[Model]] object. If the parameter is not provided or empty, the default set of fields as defined |
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23 | * by [[Model::fields()]] will be returned. |
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24 | */ |
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25 | public $fieldsParam = 'fields'; |
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26 | /** |
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27 | * @var string the name of the query parameter containing the information about which fields should be returned |
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28 | * in addition to those listed in [[fieldsParam]] for a resource object. |
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29 | */ |
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30 | public $expandParam = 'include'; |
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31 | /** |
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32 | * @var string the name of the envelope (e.g. `_links`) for returning the links objects. |
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33 | * It takes effect only, if `collectionEnvelope` is set. |
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34 | * @since 2.0.4 |
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35 | */ |
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36 | public $linksEnvelope = 'links'; |
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37 | /** |
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38 | * @var string the name of the envelope (e.g. `_meta`) for returning the pagination object. |
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39 | * It takes effect only, if `collectionEnvelope` is set. |
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40 | * @since 2.0.4 |
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41 | */ |
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42 | public $metaEnvelope = 'meta'; |
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43 | /** |
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44 | * @var Request the current request. If not set, the `request` application component will be used. |
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45 | */ |
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46 | public $request; |
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47 | /** |
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48 | * @var Response the response to be sent. If not set, the `response` application component will be used. |
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49 | */ |
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50 | public $response; |
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51 | |||
52 | |||
53 | /** |
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54 | * @inheritdoc |
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55 | */ |
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56 | public function init() |
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65 | |||
66 | /** |
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67 | * Serializes the given data into a format that can be easily turned into other formats. |
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68 | * This method mainly converts the objects of recognized types into array representation. |
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69 | * It will not do conversion for unknown object types or non-object data. |
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70 | * @param mixed $data the data to be serialized. |
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71 | * @return mixed the converted data. |
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72 | */ |
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73 | public function serialize($data) |
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85 | |||
86 | /** |
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87 | * @param ResourceInterface $model |
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88 | * @return array |
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89 | */ |
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90 | protected function serializeModel(ResourceInterface $model) |
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131 | |||
132 | /** |
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133 | * @param ResourceInterface $resource |
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134 | * @return array |
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135 | */ |
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136 | protected function serializeResource(ResourceInterface $resource) |
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151 | |||
152 | /** |
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153 | * Serialize resource identifier object and make type juggling |
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154 | * @link http://jsonapi.org/format/#document-resource-object-identification |
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155 | * @param ResourceIdentifierInterface $identifier |
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156 | * @return array |
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157 | */ |
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158 | protected function serializeIdentifier(ResourceIdentifierInterface $identifier) |
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171 | |||
172 | /** |
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173 | * @param ResourceInterface $resource |
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174 | * @return array |
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175 | */ |
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176 | protected function serializeIncluded($resource) |
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196 | |||
197 | /** |
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198 | * Serializes a data provider. |
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199 | * @param DataProviderInterface $dataProvider |
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200 | * @return array the array representation of the data provider. |
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201 | */ |
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202 | protected function serializeDataProvider($dataProvider) |
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234 | |||
235 | /** |
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236 | * Serializes a pagination into an array. |
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237 | * @param Pagination $pagination |
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238 | * @return array the array representation of the pagination |
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239 | * @see addPaginationHeaders() |
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240 | */ |
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241 | protected function serializePagination($pagination) |
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253 | |||
254 | /** |
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255 | * Serializes the validation errors in a model. |
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256 | * @param Model $model |
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257 | * @return array the array representation of the errors |
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258 | */ |
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259 | protected function serializeModelErrors($model) |
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272 | |||
273 | /** |
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274 | * @return array |
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275 | */ |
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276 | protected function getRequestedFields() |
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288 | |||
289 | protected function getIncluded() |
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294 | } |
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295 |
This check looks for multiple assignments in successive lines of code. It will report an issue if the operators are not in a straight line.
To visualize
will produce issues in the first and second line, while this second example
will produce no issues.