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 Model 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 Model, and based on these observations, apply Extract Interface, too.
1 | <?php |
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15 | class Model extends AbstractModel |
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16 | { |
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17 | /** |
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18 | * The id value of this model. |
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19 | * Always converted to a string when in the model context. |
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20 | * |
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21 | * @var string |
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22 | */ |
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23 | protected $identifier; |
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24 | |||
25 | /** |
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26 | * The Model's has-one relationships |
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27 | * |
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28 | * @var Relationships\HasOne |
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29 | */ |
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30 | protected $hasOneRelationships; |
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31 | |||
32 | /** |
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33 | * The Model's has-many relationships |
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34 | * |
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35 | * @var Relationships\HasMany |
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36 | */ |
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37 | protected $hasManyRelationships; |
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38 | |||
39 | /** |
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40 | * Enables/disables collection auto-initialization on iteration. |
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41 | * Will not load/fill the collection from the database if false. |
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42 | * Is useful for large hasMany iterations where only id and type are required (ala serialization). |
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43 | * |
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44 | * @var bool |
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45 | */ |
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46 | protected $collectionAutoInit = true; |
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47 | |||
48 | /** |
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49 | * Constructor. |
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50 | * |
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51 | * @param EntityMetadata $metadata The internal entity metadata that supports this Model. |
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52 | * @param string $identifier The database identifier. |
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53 | * @param Store $store The model store service for handling persistence operations. |
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54 | * @param array|null $properties The model's properties from the db layer to init the model with. New models will constructed with a null record. |
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55 | */ |
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56 | public function __construct(EntityMetadata $metadata, $identifier, Store $store, array $properties = null) |
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61 | |||
62 | /** |
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63 | * Cloner. |
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64 | * Ensures sub objects are also cloned. |
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65 | * |
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66 | */ |
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67 | public function __clone() |
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73 | |||
74 | /** |
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75 | * {@inheritdoc} |
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76 | * |
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77 | * Overloaded to support relationships. |
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78 | * |
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79 | */ |
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80 | public function apply(array $properties) |
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110 | |||
111 | /** |
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112 | * {@inheritdoc} |
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113 | * |
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114 | * Overloaded to support relationships. |
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115 | */ |
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116 | View Code Duplication | public function clear($key) |
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132 | |||
133 | /** |
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134 | * Enables or disables has-many collection auto-initialization from the database. |
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135 | * |
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136 | * @param bool $bit Whether to enable/disable. |
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137 | * @return self |
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138 | */ |
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139 | public function enableCollectionAutoInit($bit = true) |
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144 | |||
145 | /** |
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146 | * Marks the record for deletion. |
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147 | * Will not remove from the database until $this->save() is called. |
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148 | * |
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149 | * @api |
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150 | * @return self |
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151 | * @throws \RuntimeException If a new (unsaved) model is deleted. |
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152 | */ |
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153 | public function delete() |
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164 | |||
165 | /** |
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166 | * {@inheritdoc} |
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167 | * |
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168 | * Overloaded to support relationships. |
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169 | * |
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170 | */ |
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171 | public function get($key) |
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178 | |||
179 | /** |
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180 | * {@inheritdoc} |
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181 | * |
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182 | * Overloaded to support relationships. |
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183 | * |
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184 | */ |
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185 | public function getChangeSet() |
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192 | |||
193 | /** |
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194 | * Gets the composite key of the model by combining the model type with the unique id. |
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195 | * |
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196 | * @api |
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197 | * @return string |
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198 | */ |
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199 | public function getCompositeKey() |
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203 | |||
204 | /** |
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205 | * Gets the unique identifier of this model. |
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206 | * |
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207 | * @api |
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208 | * @return string |
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209 | */ |
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210 | public function getId() |
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214 | |||
215 | /** |
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216 | * Gets the model type. |
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217 | * |
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218 | * @api |
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219 | * @return string |
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220 | */ |
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221 | public function getType() |
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225 | |||
226 | /** |
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227 | * {@inheritdoc} |
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228 | * |
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229 | * Overloaded to support relationships. |
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230 | * |
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231 | */ |
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232 | public function initialize(array $properties = null) |
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263 | |||
264 | /** |
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265 | * {@inheritdoc} |
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266 | * |
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267 | * Overloaded to support relationships. |
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268 | * |
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269 | */ |
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270 | public function isDirty() |
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277 | |||
278 | /** |
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279 | * Determines if a property key is a has-many relationship. |
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280 | * |
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281 | * @api |
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282 | * @param string $key The property key. |
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283 | * @return bool |
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284 | */ |
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285 | public function isHasMany($key) |
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292 | |||
293 | /** |
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294 | * Determines if a property key is a has-one relationship. |
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295 | * |
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296 | * @api |
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297 | * @param string $key The property key. |
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298 | * @return bool |
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299 | */ |
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300 | public function isHasOne($key) |
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307 | |||
308 | /** |
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309 | * Determines if a property key is a an inverse relationship. |
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310 | * |
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311 | * @api |
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312 | * @param string $key The property key. |
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313 | * @return bool |
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314 | */ |
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315 | public function isInverse($key) |
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322 | |||
323 | /** |
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324 | * Determines if a property key is a relationship (either has-one or has-many). |
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325 | * |
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326 | * @api |
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327 | * @param string $key The property key. |
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328 | * @return bool |
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329 | */ |
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330 | public function isRelationship($key) |
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334 | |||
335 | /** |
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336 | * Pushes a Model into a has-many relationship collection. |
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337 | * This method must be used for has-many relationships. Direct set is not supported. |
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338 | * To completely replace a has-many, call clear() first and then push() the new Models. |
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339 | * |
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340 | * @api |
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341 | * @param string $key |
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342 | * @param Model $model |
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343 | * @return self |
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344 | */ |
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345 | View Code Duplication | public function push($key, Model $model) |
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362 | |||
363 | /** |
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364 | * Reloads the model from the database. |
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365 | * |
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366 | * @api |
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367 | * @return self |
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368 | */ |
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369 | public function reload() |
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373 | |||
374 | /** |
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375 | * Removes a specific Model from a has-many relationship collection. |
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376 | * |
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377 | * @api |
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378 | * @param string $key The has-many relationship key. |
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379 | * @param Model $model The model to remove from the collection. |
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380 | * @return self |
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381 | */ |
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382 | View Code Duplication | public function remove($key, Model $model) |
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396 | |||
397 | /** |
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398 | * {@inheritdoc} |
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399 | * Overloaded to support relationship rollback. |
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400 | */ |
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401 | public function rollback() |
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407 | |||
408 | /** |
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409 | * {@inheritdoc} |
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410 | * |
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411 | * Overloaded to support relationships. |
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412 | * Sets a model property: an attribute value, a has-one model, or an entire has-many model collection. |
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413 | * Note: To push/remove a single Model into a has-many collection, or clear a collection, use @see push(), remove() and clear(). |
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414 | * |
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415 | */ |
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416 | public function set($key, $value) |
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423 | |||
424 | /** |
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425 | * Saves the model. |
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426 | * |
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427 | * @api |
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428 | * @param Implement cascade relationship saves. Or should the store handle this? |
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429 | * @return self |
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430 | */ |
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431 | public function save() |
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439 | |||
440 | /** |
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441 | * {@inheritdoc} |
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442 | * |
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443 | * Overloaded to support relationships. |
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444 | */ |
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445 | protected function filterNotSavedProperties(array $properties) |
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455 | |||
456 | /** |
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457 | * {@inheritdoc} |
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458 | * |
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459 | * Overloaded to support global model defaults. |
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460 | * |
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461 | */ |
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462 | protected function applyDefaultAttrValues(array $attributes = []) |
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475 | |||
476 | /** |
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477 | * Gets a relationship value. |
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478 | * |
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479 | * @param string $key The relationship key (field) name. |
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480 | * @return Model|array|null |
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481 | * @throws \RuntimeException If hasMany relationships are accessed directly. |
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482 | */ |
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483 | protected function getRelationship($key) |
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499 | |||
500 | /** |
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501 | * Sets a has-one relationship. |
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502 | * |
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503 | * @param string $key The relationship key (field) name. |
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504 | * @param Model|null $model The model to relate. |
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505 | * @return self |
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506 | */ |
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507 | View Code Duplication | protected function setHasOne($key, Model $model = null) |
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520 | |||
521 | /** |
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522 | * Sets a relationship value. |
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523 | * |
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524 | * @param string $key |
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525 | * @param Model|null $value |
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526 | * @return self |
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527 | */ |
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528 | protected function setRelationship($key, $value) |
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538 | |||
539 | /** |
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540 | * {@inheritdoc} |
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541 | * |
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542 | * Overloaded to handle loading from the database. |
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543 | * If the model is currently empty, it will query the database and fill/load the model. |
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544 | * |
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545 | */ |
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546 | protected function touch($force = false) |
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558 | |||
559 | /** |
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560 | * Validates that the model type (from a Model or Collection instance) can be set to the relationship field. |
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561 | * |
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562 | * @param string $relKey The relationship field key. |
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563 | * @param string $type The model type that is being related. |
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564 | * @return self |
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565 | */ |
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566 | protected function validateRelSet($relKey, $type) |
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573 | } |
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574 |
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: