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 FormElement 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 FormElement, and based on these observations, apply Extract Interface, too.
1 | <?php |
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8 | abstract class FormElement implements \ArrayAccess |
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9 | { |
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10 | |||
11 | /** |
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12 | * @var array $attributes settings to use to create element |
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13 | * @var array $config default settings to use to create element |
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14 | * @var array $characterEncoding setting for character encoding |
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15 | */ |
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16 | public $attributes; |
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17 | public $config; |
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18 | public $characterEncoding; |
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19 | |||
20 | |||
21 | |||
22 | /** |
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23 | * Constructor creating a form element. |
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24 | * |
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25 | * @param string $name of the element. |
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26 | * @param array $attributes to set to the element. Default is an empty |
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27 | * array. |
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28 | */ |
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29 | 21 | public function __construct($name, $attributes = []) |
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40 | |||
41 | |||
42 | |||
43 | /** |
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44 | * Set default values to use, merge incoming with existing. |
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45 | * |
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46 | * @param array $options key value array with settings to use. |
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47 | * |
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48 | * @return void |
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49 | */ |
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50 | public function setDefault($options) |
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54 | |||
55 | |||
56 | |||
57 | /** |
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58 | * Implementing ArrayAccess for this->attributes |
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59 | * |
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60 | * @return void |
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61 | */ |
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62 | 21 | public function offsetSet($offset, $value) |
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70 | |||
71 | |||
72 | |||
73 | /** |
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74 | * Implementing ArrayAccess for this->attributes |
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75 | */ |
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76 | 21 | public function offsetExists($offset) |
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80 | |||
81 | |||
82 | |||
83 | /** |
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84 | * Implementing ArrayAccess for this->attributes |
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85 | */ |
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86 | public function offsetUnset($offset) |
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90 | |||
91 | |||
92 | |||
93 | /** |
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94 | * Implementing ArrayAccess for this->attributes |
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95 | */ |
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96 | 20 | public function offsetGet($offset) |
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100 | |||
101 | |||
102 | |||
103 | /** |
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104 | * Get id of an element. |
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105 | * |
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106 | * @return HTML code for the element. |
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107 | */ |
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108 | 9 | public function getElementId() |
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112 | |||
113 | |||
114 | |||
115 | /** |
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116 | * Get alll validation messages. |
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117 | * |
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118 | * @return HTML code for the element. |
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119 | */ |
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120 | 9 | public function getValidationMessages() |
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132 | |||
133 | |||
134 | |||
135 | /** |
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136 | * Get details for a HTML element, prepare for creating HTML code for it. |
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137 | * |
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138 | * @return HTML code for the element. |
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139 | */ |
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140 | 9 | public function getHTMLDetails() |
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305 | |||
306 | |||
307 | |||
308 | /** |
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309 | * Get HTML code for a element, must be implemented by each subclass. |
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310 | * |
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311 | * @return HTML code for the element. |
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312 | */ |
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313 | abstract public function getHTML(); |
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314 | |||
315 | |||
316 | |||
317 | /** |
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318 | * Validate the form element value according a ruleset. |
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319 | * |
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320 | * @param array $rules validation rules. |
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321 | * @param Form|null $form the parent form. |
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322 | * |
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323 | * @return boolean true if all rules pass, else false. |
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324 | */ |
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325 | 2 | public function validate($rules, $form = null) |
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407 | |||
408 | |||
409 | |||
410 | /** |
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411 | * Use the element name as label if label is not set. |
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412 | * |
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413 | * @param string $append a colon as default to the end of the label. |
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414 | * |
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415 | * @return void |
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416 | */ |
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417 | 14 | public function useNameAsDefaultLabel($append = ':') |
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423 | |||
424 | |||
425 | |||
426 | /** |
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427 | * Use the element name as value if value is not set. |
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428 | * |
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429 | * @return void |
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430 | */ |
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431 | 3 | public function useNameAsDefaultValue() |
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437 | |||
438 | |||
439 | |||
440 | /** |
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441 | * Get the value of the form element. |
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442 | * |
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443 | * @return mixed the value of the form element. |
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444 | */ |
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445 | 6 | public function getValue() |
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449 | |||
450 | |||
451 | |||
452 | /** |
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453 | * Get the value of the form element. |
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454 | * |
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455 | * @return mixed the value of the form element. |
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456 | */ |
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457 | public function value() |
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461 | |||
462 | |||
463 | |||
464 | /** |
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465 | * Get the status of the form element if it is checked or not. |
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466 | * |
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467 | * @return mixed the value of the form element. |
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468 | */ |
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469 | public function checked() |
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473 | } |
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474 |
In PHP it is possible to write to properties without declaring them. For example, the following is perfectly valid PHP code:
Generally, it is a good practice to explictly declare properties to avoid accidental typos and provide IDE auto-completion: