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 HasDuplicates 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 HasDuplicates, and based on these observations, apply Extract Interface, too.
1 | <?php |
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13 | trait HasDuplicates |
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14 | { |
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15 | /** |
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16 | * The container for all the options necessary for this trait. |
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17 | * Options can be viewed in the Neurony\Duplicate\Options\DuplicateOptions file. |
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18 | * |
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19 | * @var DuplicateOptions |
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20 | */ |
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21 | protected $duplicateOptions; |
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22 | |||
23 | /** |
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24 | * Set the options for the HasDuplicates trait. |
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25 | * |
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26 | * @return DuplicateOptions |
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27 | */ |
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28 | abstract public function getDuplicateOptions(): DuplicateOptions; |
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29 | |||
30 | /** |
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31 | * Register a duplicating model event with the dispatcher. |
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32 | * |
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33 | * @param Closure|string $callback |
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34 | * @return void |
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35 | */ |
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36 | public static function duplicating($callback): void |
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40 | |||
41 | /** |
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42 | * Register a duplicated model event with the dispatcher. |
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43 | * |
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44 | * @param Closure|string $callback |
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45 | * @return void |
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46 | */ |
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47 | public static function duplicated($callback): void |
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51 | |||
52 | /** |
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53 | * Duplicate a model instance and it's relations. |
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54 | * |
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55 | * @return Model|bool |
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56 | * @throws Exception |
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57 | */ |
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58 | public function saveAsDuplicate() |
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94 | |||
95 | /** |
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96 | * Get a replicated instance of the original model's instance. |
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97 | * |
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98 | * @return Model |
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99 | * @throws Exception |
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100 | */ |
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101 | protected function duplicateModel(): Model |
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110 | |||
111 | /** |
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112 | * Duplicate a direct relation. |
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113 | * Subsequently save new relation records for the initial model instance. |
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114 | * |
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115 | * @param Model $model |
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116 | * @param string $relation |
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117 | * @return Model |
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118 | * @throws Exception |
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119 | */ |
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120 | protected function duplicateDirectRelation(Model $model, string $relation): Model |
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131 | |||
132 | /** |
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133 | * Duplicate a pivoted relation. |
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134 | * Subsequently attach new pivot records corresponding to the relation for the initial model instance. |
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135 | * |
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136 | * @param Model $model |
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137 | * @param string $relation |
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138 | * @return Model |
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139 | * @throws Exception |
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140 | */ |
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141 | protected function duplicatePivotedRelation(Model $model, string $relation): Model |
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151 | |||
152 | /** |
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153 | * Get the relations that should be duplicated alongside the original model. |
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154 | * |
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155 | * @return array |
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156 | * @throws \ReflectionException |
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157 | */ |
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158 | protected function getRelationsForDuplication(): array |
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171 | |||
172 | /** |
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173 | * Replicate a model instance, excluding attributes provided in the model's getDuplicateOptions() method. |
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174 | * |
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175 | * @return Model |
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176 | */ |
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177 | private function duplicateModelWithExcluding(): Model |
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195 | |||
196 | /** |
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197 | * Update a model instance. |
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198 | * With unique values for the attributes provided in the model's getDuplicateOptions() method. |
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199 | * |
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200 | * @param Model $model |
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201 | * @return Model |
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202 | */ |
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203 | private function duplicateModelWithUnique(Model $model): Model |
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224 | |||
225 | /** |
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226 | * Replicate a model relation instance, excluding attributes provided in the model's getDuplicateOptions() method. |
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227 | * |
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228 | * @param Model $model |
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229 | * @param string $relation |
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230 | * @return Model |
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231 | */ |
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232 | private function duplicateRelationWithExcluding(Model $model, string $relation): Model |
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245 | |||
246 | /** |
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247 | * Update a relation for the model instance. |
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248 | * With unique values for the attributes attributes provided in the model's getDuplicateOptions() method. |
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249 | * |
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250 | * @param Model $model |
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251 | * @param string $relation |
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252 | * @return Model |
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253 | */ |
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254 | private function duplicateRelationWithUnique(Model $model, string $relation): Model |
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277 | |||
278 | /** |
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279 | * Get additional pivot attributes that should be saved when duplicating a pivoted relation. |
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280 | * Usually, these are attributes coming from the withPivot() method defined on the relation. |
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281 | * |
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282 | * @param Model $model |
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283 | * @return array |
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284 | */ |
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285 | protected function establishDuplicatablePivotAttributes(Model $model): array |
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297 | |||
298 | /** |
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299 | * Instantiate the duplicate options. |
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300 | * |
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301 | * @return void |
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302 | */ |
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303 | protected function initDuplicateOptions(): void |
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309 | } |
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310 |
This check looks for methods that are used by a trait but not required by it.
To illustrate, let’s look at the following code example
The trait
Idable
provides a methodequalsId
that in turn relies on the methodgetId()
. If this method does not exist on a class mixing in this trait, the method will fail.Adding the
getId()
as an abstract method to the trait will make sure it is available.