Complex classes like CollectionLoader 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 CollectionLoader, and based on these observations, apply Extract Interface, too.
1 | <?php |
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27 | class CollectionLoader implements LoggerAwareInterface |
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28 | { |
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29 | use LoggerAwareTrait; |
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30 | |||
31 | /** |
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32 | * The source to load objects from. |
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33 | * |
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34 | * @var SourceInterface |
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35 | */ |
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36 | private $source; |
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37 | |||
38 | /** |
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39 | * The model to load the collection from. |
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40 | * |
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41 | * @var ModelInterface |
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42 | */ |
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43 | private $model; |
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44 | |||
45 | /** |
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46 | * Store the factory instance for the current class. |
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47 | * |
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48 | * @var FactoryInterface |
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49 | */ |
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50 | private $factory; |
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51 | |||
52 | /** |
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53 | * The callback routine applied to every object added to the collection. |
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54 | * |
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55 | * @var callable|null |
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56 | */ |
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57 | private $callback; |
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58 | |||
59 | /** |
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60 | * The field which defines the data's model. |
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61 | * |
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62 | * @var string|null |
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63 | */ |
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64 | private $dynamicTypeField; |
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65 | |||
66 | /** |
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67 | * The class name of the collection to use. |
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68 | * |
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69 | * Must be a fully-qualified PHP namespace and an implementation of {@see ArrayAccess}. |
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70 | * |
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71 | * @var string |
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72 | */ |
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73 | private $collectionClass = Collection::class; |
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74 | |||
75 | /** |
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76 | * Return a new CollectionLoader object. |
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77 | * |
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78 | * @param array $data The loader's dependencies. |
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79 | */ |
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80 | public function __construct(array $data) |
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100 | |||
101 | /** |
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102 | * Set an object model factory. |
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103 | * |
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104 | * @param FactoryInterface $factory The model factory, to create objects. |
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105 | * @return CollectionLoader Chainable |
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106 | */ |
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107 | public function setFactory(FactoryInterface $factory) |
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113 | |||
114 | /** |
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115 | * Retrieve the object model factory. |
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116 | * |
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117 | * @throws RuntimeException If the model factory was not previously set. |
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118 | * @return FactoryInterface |
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119 | */ |
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120 | protected function factory() |
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130 | |||
131 | /** |
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132 | * Set the loader data. |
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133 | * |
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134 | * @param array $data Data to assign to the loader. |
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135 | * @return CollectionLoader Chainable |
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136 | */ |
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137 | public function setData(array $data) |
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151 | |||
152 | /** |
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153 | * Retrieve the source to load objects from. |
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154 | * |
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155 | * @throws RuntimeException If no source has been defined. |
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156 | * @return mixed |
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157 | */ |
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158 | public function source() |
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166 | |||
167 | /** |
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168 | * Set the source to load objects from. |
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169 | * |
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170 | * @param SourceInterface $source A data source. |
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171 | * @return CollectionLoader Chainable |
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172 | */ |
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173 | public function setSource(SourceInterface $source) |
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181 | |||
182 | /** |
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183 | * Reset everything but the model. |
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184 | * |
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185 | * @return CollectionLoader Chainable |
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186 | */ |
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187 | public function reset() |
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198 | |||
199 | /** |
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200 | * Retrieve the object model. |
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201 | * |
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202 | * @throws RuntimeException If no model has been defined. |
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203 | * @return Model |
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204 | */ |
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205 | public function model() |
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213 | |||
214 | /** |
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215 | * Determine if the loader has an object model. |
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216 | * |
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217 | * @return boolean |
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218 | */ |
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219 | public function hasModel() |
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223 | |||
224 | /** |
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225 | * Set the model to use for the loaded objects. |
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226 | * |
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227 | * @param string|ModelInterface $model An object model. |
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228 | * @throws InvalidArgumentException If the given argument is not a model. |
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229 | * @return CollectionLoader CHainable |
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230 | */ |
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231 | public function setModel($model) |
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252 | |||
253 | /** |
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254 | * @param string $field The field to use for dynamic object type. |
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255 | * @throws InvalidArgumentException If the field is not a string. |
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256 | * @return CollectionLoader Chainable |
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257 | */ |
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258 | public function setDynamicTypeField($field) |
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270 | |||
271 | /** |
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272 | * Alias of {@see SourceInterface::properties()} |
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273 | * |
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274 | * @return array |
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275 | */ |
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276 | public function properties() |
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280 | |||
281 | /** |
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282 | * Alias of {@see SourceInterface::setProperties()} |
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283 | * |
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284 | * @param array $properties An array of property identifiers. |
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285 | * @return CollectionLoader Chainable |
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286 | */ |
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287 | public function setProperties(array $properties) |
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293 | |||
294 | /** |
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295 | * Alias of {@see SourceInterface::addProperty()} |
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296 | * |
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297 | * @param string $property A property identifier. |
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298 | * @return CollectionLoader Chainable |
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299 | */ |
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300 | public function addProperty($property) |
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306 | |||
307 | /** |
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308 | * Set "search" keywords to filter multiple properties. |
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309 | * |
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310 | * @param array $keywords An array of keywords and properties. |
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311 | * @return CollectionLoader Chainable |
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312 | */ |
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313 | public function setKeywords(array $keywords) |
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323 | |||
324 | /** |
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325 | * Add a "search" keyword filter to multiple properties. |
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326 | * |
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327 | * @param string $keyword A value to match among $properties. |
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328 | * @param array $properties An array of property identifiers. |
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329 | * @return CollectionLoader Chainable |
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330 | */ |
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331 | public function addKeyword($keyword, array $properties = null) |
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349 | |||
350 | /** |
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351 | * Alias of {@see SourceInterface::filters()} |
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352 | * |
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353 | * @return array |
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354 | */ |
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355 | public function filters() |
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359 | |||
360 | /** |
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361 | * Alias of {@see SourceInterface::setFilters()} |
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362 | * |
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363 | * @param array $filters An array of filters. |
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364 | * @return Collection Chainable |
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365 | */ |
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366 | public function setFilters(array $filters) |
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372 | |||
373 | /** |
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374 | * Alias of {@see SourceInterface::addFilters()} |
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375 | * |
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376 | * @param array $filters An array of filters. |
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377 | * @return Collection Chainable |
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378 | */ |
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379 | public function addFilters(array $filters) |
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387 | |||
388 | /** |
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389 | * Alias of {@see SourceInterface::addFilter()} |
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390 | * |
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391 | * @param string|array|Filter $param A property identifier, filter array, or Filter object. |
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392 | * @param mixed $val Optional. The value to match. Only used if the first argument is a string. |
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393 | * @param array $options Optional. Filter options. Only used if the first argument is a string. |
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394 | * @return CollectionLoader Chainable |
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395 | */ |
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396 | public function addFilter($param, $val = null, array $options = null) |
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402 | |||
403 | /** |
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404 | * Alias of {@see SourceInterface::orders()} |
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405 | * |
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406 | * @return array |
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407 | */ |
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408 | public function orders() |
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412 | |||
413 | /** |
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414 | * Alias of {@see SourceInterface::setOrders()} |
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415 | * |
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416 | * @param array $orders An array of orders. |
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417 | * @return CollectionLoader Chainable |
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418 | */ |
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419 | public function setOrders(array $orders) |
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425 | |||
426 | /** |
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427 | * Alias of {@see SourceInterface::addOrders()} |
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428 | * |
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429 | * @param array $orders An array of orders. |
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430 | * @return Collection Chainable |
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431 | */ |
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432 | public function addOrders(array $orders) |
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440 | |||
441 | /** |
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442 | * Alias of {@see SourceInterface::addOrder()} |
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443 | * |
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444 | * @param string|array|Order $param A property identifier, order array, or Order object. |
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445 | * @param string $mode Optional. Sort order. Only used if the first argument is a string. |
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446 | * @param array $orderOptions Optional. Filter options. Only used if the first argument is a string. |
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447 | * @return CollectionLoader Chainable |
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448 | */ |
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449 | public function addOrder($param, $mode = 'asc', array $orderOptions = null) |
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455 | |||
456 | /** |
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457 | * Alias of {@see SourceInterface::pagination()} |
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458 | * |
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459 | * @return Pagination |
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460 | */ |
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461 | public function pagination() |
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465 | |||
466 | /** |
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467 | * Alias of {@see SourceInterface::setPagination()} |
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468 | * |
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469 | * @param mixed $param An associative array of pagination settings. |
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470 | * @return CollectionLoader Chainable |
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471 | */ |
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472 | public function setPagination($param) |
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478 | |||
479 | /** |
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480 | * Alias of {@see PaginationInterface::page()} |
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481 | * |
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482 | * @return integer |
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483 | */ |
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484 | public function page() |
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488 | |||
489 | /** |
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490 | * Alias of {@see PaginationInterface::pagination()} |
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491 | * |
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492 | * @param integer $page A page number. |
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493 | * @return CollectionLoader Chainable |
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494 | */ |
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495 | public function setPage($page) |
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501 | |||
502 | /** |
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503 | * Alias of {@see PaginationInterface::numPerPage()} |
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504 | * |
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505 | * @return integer |
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506 | */ |
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507 | public function numPerPage() |
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511 | |||
512 | /** |
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513 | * Alias of {@see PaginationInterface::setNumPerPage()} |
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514 | * |
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515 | * @param integer $num The number of items to display per page. |
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516 | * @return CollectionLoader Chainable |
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517 | */ |
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518 | public function setNumPerPage($num) |
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524 | |||
525 | /** |
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526 | * Set the callback routine applied to every object added to the collection. |
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527 | * |
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528 | * @param callable $callback The callback routine. |
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529 | * @return CollectionLoader Chainable |
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530 | */ |
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531 | public function setCallback(callable $callback) |
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537 | |||
538 | /** |
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539 | * Retrieve the callback routine applied to every object added to the collection. |
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540 | * |
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541 | * @return callable|null |
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542 | */ |
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543 | public function callback() |
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547 | |||
548 | /** |
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549 | * Load a collection from source. |
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550 | * |
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551 | * @param string|null $ident Optional. A pre-defined list to use from the model. |
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552 | * @param callable|null $callback Process each entity after applying raw data. |
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553 | * Leave blank to use {@see CollectionLoader::callback()}. |
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554 | * @param callable|null $before Process each entity before applying raw data. |
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555 | * @throws Exception If the database connection fails. |
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556 | * @return ModelInterface[]|ArrayAccess |
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557 | */ |
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558 | public function load($ident = null, callable $callback = null, callable $before = null) |
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567 | |||
568 | /** |
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569 | * Get the total number of items for this collection query. |
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570 | * |
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571 | * @throws RuntimeException If the database connection fails. |
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572 | * @return integer |
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573 | */ |
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574 | public function loadCount() |
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592 | |||
593 | /** |
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594 | * Load list from query. |
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595 | * |
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596 | * **Example — Binding values to $query** |
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597 | * |
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598 | * ```php |
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599 | * $this->loadFromQuery([ |
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600 | * 'SELECT name, colour, calories FROM fruit WHERE calories < :calories AND colour = :colour', |
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601 | * [ |
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602 | * 'calories' => 150, |
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603 | * 'colour' => 'red' |
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604 | * ], |
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605 | * [ 'calories' => PDO::PARAM_INT ] |
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606 | * ]); |
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607 | * ``` |
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608 | * |
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609 | * @param string|array $query The SQL query as a string or an array composed of the query, |
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610 | * parameter binds, and types of parameter bindings. |
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611 | * @param callable|null $callback Process each entity after applying raw data. |
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612 | * Leave blank to use {@see CollectionLoader::callback()}. |
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613 | * @param callable|null $before Process each entity before applying raw data. |
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614 | * @throws RuntimeException If the database connection fails. |
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615 | * @throws InvalidArgumentException If the SQL string/set is invalid. |
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616 | * @return ModelInterface[]|ArrayAccess |
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617 | */ |
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618 | public function loadFromQuery($query, callable $callback = null, callable $before = null) |
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653 | |||
654 | /** |
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655 | * Process the collection of raw data. |
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656 | * |
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657 | * @param mixed[]|Traversable $results The raw result set. |
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658 | * @param callable|null $before Process each entity before applying raw data. |
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659 | * @param callable|null $after Process each entity after applying raw data. |
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660 | * @return ModelInterface[]|ArrayAccess |
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661 | */ |
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662 | protected function processCollection($results, callable $before = null, callable $after = null) |
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675 | |||
676 | /** |
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677 | * Process the raw data for one model. |
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678 | * |
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679 | * @param mixed $objData The raw dataset. |
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680 | * @param callable|null $before Process each entity before applying raw data. |
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681 | * @param callable|null $after Process each entity after applying raw data. |
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682 | * @return ModelInterface|ArrayAccess|null |
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683 | */ |
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684 | protected function processModel($objData, callable $before = null, callable $after = null) |
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706 | |||
707 | /** |
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708 | * Create a collection class or array. |
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709 | * |
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710 | * @throws RuntimeException If the collection class is invalid. |
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711 | * @return array|ArrayAccess |
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712 | */ |
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713 | public function createCollection() |
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738 | |||
739 | /** |
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740 | * Set the class name of the collection. |
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741 | * |
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742 | * @param string $className The class name of the collection. |
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743 | * @throws InvalidArgumentException If the class name is not a string. |
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744 | * @return AbstractPropertyDisplay Chainable |
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745 | */ |
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746 | public function setCollectionClass($className) |
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758 | |||
759 | /** |
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760 | * Retrieve the class name of the collection. |
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761 | * |
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762 | * @return string |
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763 | */ |
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764 | public function collectionClass() |
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768 | |||
769 | /** |
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770 | * Allow an object to define how the key getter are called. |
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771 | * |
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772 | * @param string $key The key to get the getter from. |
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773 | * @return string The getter method name, for a given key. |
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774 | */ |
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775 | protected function getter($key) |
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780 | |||
781 | /** |
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782 | * Allow an object to define how the key setter are called. |
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783 | * |
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784 | * @param string $key The key to get the setter from. |
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785 | * @return string The setter method name, for a given key. |
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786 | */ |
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787 | protected function setter($key) |
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792 | |||
793 | /** |
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794 | * Transform a snake_case string to camelCase. |
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795 | * |
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796 | * @param string $str The snake_case string to camelize. |
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797 | * @return string The camelcase'd string. |
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798 | */ |
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799 | protected function camelize($str) |
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803 | } |
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804 |
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different implementation of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the interface: