Complex classes like FormHelper 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 FormHelper, and based on these observations, apply Extract Interface, too.
1 | <?php namespace Kris\LaravelFormBuilder; |
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11 | class FormHelper |
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12 | { |
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13 | |||
14 | /** |
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15 | * @var View |
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16 | */ |
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17 | protected $view; |
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18 | |||
19 | /** |
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20 | * @var TranslatorInterface |
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21 | */ |
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22 | protected $translator; |
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23 | |||
24 | /** |
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25 | * @var array |
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26 | */ |
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27 | protected $config; |
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28 | |||
29 | /** |
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30 | * @var FormBuilder |
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31 | */ |
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32 | protected $formBuilder; |
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33 | |||
34 | /** |
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35 | * @var array |
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36 | */ |
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37 | protected static $reservedFieldNames = [ |
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38 | 'save' |
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39 | ]; |
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40 | |||
41 | /** |
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42 | * All available field types |
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43 | * |
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44 | * @var array |
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45 | */ |
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46 | protected static $availableFieldTypes = [ |
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47 | 'text' => 'InputType', |
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48 | 'email' => 'InputType', |
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49 | 'url' => 'InputType', |
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50 | 'tel' => 'InputType', |
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51 | 'search' => 'InputType', |
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52 | 'password' => 'InputType', |
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53 | 'hidden' => 'InputType', |
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54 | 'number' => 'InputType', |
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55 | 'date' => 'InputType', |
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56 | 'file' => 'InputType', |
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57 | 'image' => 'InputType', |
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58 | 'color' => 'InputType', |
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59 | 'datetime-local' => 'InputType', |
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60 | 'month' => 'InputType', |
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61 | 'range' => 'InputType', |
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62 | 'time' => 'InputType', |
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63 | 'week' => 'InputType', |
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64 | 'select' => 'SelectType', |
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65 | 'textarea' => 'TextareaType', |
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66 | 'button' => 'ButtonType', |
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67 | 'submit' => 'ButtonType', |
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68 | 'reset' => 'ButtonType', |
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69 | 'radio' => 'CheckableType', |
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70 | 'checkbox' => 'CheckableType', |
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71 | 'choice' => 'ChoiceType', |
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72 | 'form' => 'ChildFormType', |
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73 | 'entity' => 'EntityType', |
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74 | 'collection' => 'CollectionType', |
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75 | 'repeated' => 'RepeatedType', |
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76 | 'static' => 'StaticType' |
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77 | ]; |
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78 | |||
79 | /** |
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80 | * Custom types |
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81 | * |
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82 | * @var array |
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83 | */ |
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84 | private $customTypes = []; |
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85 | |||
86 | /** |
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87 | * @param View $view |
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88 | * @param TranslatorInterface $translator |
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89 | * @param array $config |
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90 | */ |
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91 | 105 | public function __construct(View $view, TranslatorInterface $translator, array $config = []) |
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98 | |||
99 | /** |
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100 | * @param string $key |
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101 | * @param string $default |
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102 | * @return mixed |
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103 | */ |
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104 | 105 | public function getConfig($key, $default = null) |
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108 | |||
109 | /** |
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110 | * @return View |
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111 | */ |
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112 | 35 | public function getView() |
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116 | |||
117 | /** |
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118 | * Merge options array |
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119 | * |
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120 | * @param array $first |
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121 | * @param array $second |
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122 | * @return array |
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123 | */ |
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124 | 105 | public function mergeOptions(array $first, array $second) |
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128 | |||
129 | /** |
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130 | * Get proper class for field type |
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131 | * |
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132 | * @param $type |
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133 | * @return string |
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134 | */ |
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135 | 68 | public function getFieldType($type) |
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161 | |||
162 | /** |
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163 | * Convert array of attributes to html attributes |
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164 | * |
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165 | * @param $options |
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166 | * @return string |
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167 | */ |
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168 | 84 | public function prepareAttributes($options) |
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185 | |||
186 | /** |
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187 | * Add custom field |
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188 | * |
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189 | * @param $name |
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190 | * @param $class |
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191 | */ |
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192 | 3 | public function addCustomField($name, $class) |
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200 | |||
201 | /** |
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202 | * Load custom field types from config file |
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203 | */ |
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204 | 105 | private function loadCustomTypes() |
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214 | |||
215 | 5 | public function convertModelToArray($model) |
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231 | |||
232 | /** |
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233 | * Format the label to the proper format |
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234 | * |
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235 | * @param $name |
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236 | * @return string |
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237 | */ |
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238 | 82 | public function formatLabel($name) |
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254 | |||
255 | /** |
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256 | * @param FormField[] $fields |
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257 | * @return array |
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258 | */ |
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259 | 7 | public function mergeFieldsRules($fields) |
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279 | |||
280 | /** |
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281 | * @return array |
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282 | */ |
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283 | 2 | public function mergeAttributes($fields) |
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292 | |||
293 | /** |
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294 | * Alter a form's values recursively according to its fields |
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295 | * |
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296 | * @return void |
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297 | */ |
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298 | 2 | public function alterFieldValues(Form $form, array &$values) |
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314 | |||
315 | /** |
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316 | * @param string $string |
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317 | * @return string |
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318 | */ |
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319 | 83 | public function transformToDotSyntax($string) |
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323 | |||
324 | /** |
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325 | * @param string $string |
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326 | * @return string |
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327 | */ |
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328 | 6 | public function transformToBracketSyntax($string) |
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338 | |||
339 | /** |
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340 | * @return TranslatorInterface |
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341 | */ |
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342 | 3 | public function getTranslator() |
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346 | |||
347 | /** |
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348 | * Check if field name is valid and not reserved |
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349 | * |
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350 | * @throws \InvalidArgumentException |
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351 | * @param string $name |
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352 | * @param string $className |
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353 | */ |
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354 | 54 | public function checkFieldName($name, $className) |
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371 | } |
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372 |
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: