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 EntityMetadata 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 EntityMetadata, and based on these observations, apply Extract Interface, too.
1 | <?php |
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14 | class EntityMetadata implements Interfaces\AttributeInterface, Interfaces\EmbedInterface, Interfaces\MergeableInterface, Interfaces\MixinInterface, Interfaces\RelationshipInterface |
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15 | { |
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16 | /** |
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17 | * Uses attributes. |
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18 | */ |
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19 | use Traits\AttributesTrait; |
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20 | |||
21 | /** |
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22 | * Uses embeds. |
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23 | */ |
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24 | use Traits\EmbedsTrait; |
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25 | |||
26 | /** |
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27 | * Uses mixins. |
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28 | */ |
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29 | use Traits\MixinsTrait; |
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30 | |||
31 | /** |
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32 | * Uses merged properties. |
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33 | */ |
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34 | use Traits\PropertiesTrait; |
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35 | |||
36 | /** |
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37 | * Uses relationships. |
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38 | */ |
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39 | use Traits\RelationshipsTrait; |
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40 | |||
41 | /** |
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42 | * The id key name and type. |
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43 | */ |
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44 | const ID_KEY = 'id'; |
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45 | const ID_TYPE = 'string'; |
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46 | |||
47 | /** |
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48 | * The model type key. |
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49 | */ |
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50 | const TYPE_KEY = 'type'; |
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51 | |||
52 | /** |
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53 | * Whether this class is abstract. |
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54 | * |
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55 | * @var bool |
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56 | */ |
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57 | public $abstract = false; |
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58 | |||
59 | /** |
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60 | * An array of attribute default values for this model. |
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61 | * Keyed by field name. |
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62 | * |
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63 | * @var array |
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64 | */ |
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65 | public $defaultValues = []; |
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66 | |||
67 | /** |
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68 | * The entity type this entity extends. |
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69 | * |
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70 | * @var string|null |
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71 | */ |
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72 | public $extends; |
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73 | |||
74 | /** |
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75 | * Child entity types this entity owns. |
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76 | * Only used for polymorphic entities. |
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77 | * |
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78 | * @var array |
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79 | */ |
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80 | public $ownedTypes = []; |
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81 | |||
82 | /** |
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83 | * The persistence metadata for this entity. |
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84 | * |
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85 | * @var Interfaces\StorageLayerInterface |
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86 | */ |
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87 | public $persistence; |
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88 | |||
89 | /** |
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90 | * Whether this class is considered polymorphic. |
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91 | * |
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92 | * @var bool |
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93 | */ |
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94 | public $polymorphic = false; |
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95 | |||
96 | /** |
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97 | * The search metadata for this entity. |
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98 | * |
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99 | * @var Interfaces\StorageLayerInterface |
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100 | */ |
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101 | public $search; |
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102 | |||
103 | /** |
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104 | * Uniquely defines the type of entity. |
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105 | * |
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106 | * @var string |
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107 | */ |
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108 | public $type; |
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109 | |||
110 | /** |
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111 | * Constructor. |
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112 | * |
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113 | * @param string $type The resource identifier type. |
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114 | */ |
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115 | public function __construct($type) |
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119 | |||
120 | /** |
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121 | * Gets the parent entity type. |
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122 | * For entities that are extended. |
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123 | * |
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124 | * @return string|null |
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125 | */ |
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126 | public function getParentEntityType() |
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130 | |||
131 | /** |
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132 | * {@inheritdoc} |
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133 | */ |
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134 | public function getProperties() |
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138 | |||
139 | /** |
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140 | * Whether this metadata represents an abstract class. |
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141 | * |
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142 | * @return bool |
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143 | */ |
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144 | public function isAbstract() |
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148 | |||
149 | /** |
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150 | * Whether this metadata represents a polymorphic class. |
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151 | * |
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152 | * @return bool |
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153 | */ |
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154 | public function isPolymorphic() |
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158 | |||
159 | /** |
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160 | * Deteremines whether search is enabled for this model. |
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161 | * |
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162 | * @return bool |
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163 | */ |
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164 | public function isSearchEnabled() |
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168 | |||
169 | /** |
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170 | * Determines if this is a child entity of another entity. |
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171 | * |
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172 | * @return bool |
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173 | */ |
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174 | public function isChildEntity() |
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178 | |||
179 | /** |
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180 | * {@inheritDoc} |
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181 | */ |
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182 | public function merge(Interfaces\MergeableInterface $metadata) |
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205 | |||
206 | /** |
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207 | * Sets this metadata as representing an abstract class. |
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208 | * |
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209 | * @param bool $bit |
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210 | * @return self |
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211 | */ |
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212 | public function setAbstract($bit = true) |
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217 | |||
218 | /** |
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219 | * Sets the persistence metadata for this entity. |
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220 | * |
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221 | * @param Interfaces\StorageLayerInterface $persistence |
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222 | * @return self |
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223 | */ |
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224 | public function setPersistence(Interfaces\StorageLayerInterface $persistence) |
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229 | |||
230 | /** |
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231 | * Sets this metadata as representing a polymorphic class. |
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232 | * |
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233 | * @param bool $bit |
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234 | * @return self |
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235 | */ |
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236 | public function setPolymorphic($bit = true) |
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241 | |||
242 | /** |
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243 | * Sets the search metadata for this entity. |
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244 | * |
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245 | * @param Interfaces\StorageLayerInterface $search |
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246 | * @return self |
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247 | */ |
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248 | public function setSearch(Interfaces\StorageLayerInterface $search) |
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253 | |||
254 | /** |
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255 | * Sets the entity type. |
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256 | * |
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257 | * @param string $type |
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258 | * @return self |
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259 | * @throws MetadataException If the type is not a string or is empty. |
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260 | */ |
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261 | public function setType($type) |
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269 | |||
270 | /** |
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271 | * {@inheritdoc} |
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272 | */ |
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273 | View Code Duplication | protected function applyMixinProperties(MixinMetadata $mixin) |
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294 | |||
295 | /** |
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296 | * {@inheritdoc} |
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297 | */ |
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298 | View Code Duplication | protected function validateAttribute(AttributeMetadata $attribute) |
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307 | |||
308 | /** |
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309 | * {@inheritdoc} |
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310 | */ |
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311 | View Code Duplication | protected function validateEmbed(EmbeddedPropMetadata $embed) |
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320 | |||
321 | /** |
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322 | * {@inheritdoc} |
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323 | */ |
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324 | View Code Duplication | protected function validateRelationship(RelationshipMetadata $relationship) |
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333 | |||
334 | /** |
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335 | * Merges attributes with this instance's attributes. |
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336 | * |
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337 | * @param AttributeMetadata[] $toAdd |
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338 | * @return self |
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339 | */ |
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340 | private function mergeAttributes(array $toAdd) |
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347 | |||
348 | /** |
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349 | * Merges embeds with this instance's embeds. |
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350 | * |
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351 | * @param EmbeddedPropMetadata[] $toAdd |
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352 | * @return self |
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353 | */ |
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354 | private function mergeEmbeds(array $toAdd) |
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361 | |||
362 | /** |
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363 | * Merges mixins with this instance's mixins. |
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364 | * |
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365 | * @param MixinMetadata[] $toAdd |
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366 | * @return self |
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367 | */ |
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368 | private function mergeMixins(array $toAdd) |
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377 | |||
378 | /** |
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379 | * Merges relationships with this instance's relationships. |
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380 | * |
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381 | * @param RelationshipMetadata[] $toAdd |
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382 | * @return self |
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383 | */ |
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384 | private function mergeRelationships(array $toAdd) |
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391 | } |
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392 |
Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation.
You can also find more detailed suggestions in the “Code” section of your repository.