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 |
||
8 | abstract class FormElement implements \ArrayAccess |
||
9 | { |
||
10 | |||
11 | /** |
||
12 | * @var array $attributes settings to use to create element |
||
13 | * @var array $config default settings to use to create element |
||
14 | * @var array $characterEncoding setting for character encoding |
||
15 | */ |
||
16 | public $attributes; |
||
17 | public $config; |
||
18 | public $characterEncoding; |
||
19 | |||
20 | |||
21 | |||
22 | /** |
||
23 | * Constructor creating a form element. |
||
24 | * |
||
25 | * @param string $name of the element. |
||
26 | * @param array $attributes to set to the element. Default is an empty |
||
27 | * array. |
||
28 | */ |
||
29 | 26 | public function __construct($name, $attributes = []) |
|
41 | |||
42 | |||
43 | |||
44 | /** |
||
45 | * Set default values to use, merge incoming with existing. |
||
46 | * |
||
47 | * @param array $options key value array with settings to use. |
||
48 | * |
||
49 | * @return void |
||
50 | */ |
||
51 | 4 | public function setDefault($options) |
|
55 | |||
56 | |||
57 | |||
58 | /** |
||
59 | * Implementing ArrayAccess for this->attributes |
||
60 | * |
||
61 | * @return void |
||
62 | */ |
||
63 | 26 | public function offsetSet($offset, $value) |
|
71 | |||
72 | |||
73 | |||
74 | /** |
||
75 | * Implementing ArrayAccess for this->attributes |
||
76 | */ |
||
77 | 26 | public function offsetExists($offset) |
|
81 | |||
82 | |||
83 | |||
84 | /** |
||
85 | * Implementing ArrayAccess for this->attributes |
||
86 | */ |
||
87 | public function offsetUnset($offset) |
||
91 | |||
92 | |||
93 | |||
94 | /** |
||
95 | * Implementing ArrayAccess for this->attributes |
||
96 | */ |
||
97 | 25 | public function offsetGet($offset) |
|
101 | |||
102 | |||
103 | |||
104 | /** |
||
105 | * Get id of an element. |
||
106 | * |
||
107 | * @return HTML code for the element. |
||
108 | */ |
||
109 | 9 | public function getElementId() |
|
113 | |||
114 | |||
115 | |||
116 | /** |
||
117 | * Get alll validation messages. |
||
118 | * |
||
119 | * @return HTML code for the element. |
||
120 | */ |
||
121 | 9 | public function getValidationMessages() |
|
133 | |||
134 | |||
135 | |||
136 | /** |
||
137 | * Get details for a HTML element, prepare for creating HTML code for it. |
||
138 | * |
||
139 | * @return HTML code for the element. |
||
140 | */ |
||
141 | 9 | public function getHTMLDetails() |
|
306 | |||
307 | |||
308 | |||
309 | /** |
||
310 | * Get HTML code for a element, must be implemented by each subclass. |
||
311 | * |
||
312 | * @return HTML code for the element. |
||
313 | */ |
||
314 | abstract public function getHTML(); |
||
315 | |||
316 | |||
317 | |||
318 | /** |
||
319 | * Validate the form element value according a ruleset. |
||
320 | * |
||
321 | * @param array $rules validation rules. |
||
322 | * @param Form|null $form the parent form. |
||
323 | * |
||
324 | * @return boolean true if all rules pass, else false. |
||
325 | */ |
||
326 | 2 | public function validate($rules, $form = null) |
|
408 | |||
409 | |||
410 | |||
411 | /** |
||
412 | * Use the element name as label if label is not set. |
||
413 | * |
||
414 | * @param string $append a colon as default to the end of the label. |
||
415 | * |
||
416 | * @return void |
||
417 | */ |
||
418 | 19 | public function useNameAsDefaultLabel($append = ':') |
|
424 | |||
425 | |||
426 | |||
427 | /** |
||
428 | * Use the element name as value if value is not set. |
||
429 | * |
||
430 | * @return void |
||
431 | */ |
||
432 | 3 | public function useNameAsDefaultValue() |
|
438 | |||
439 | |||
440 | |||
441 | /** |
||
442 | * Get the value of the form element. |
||
443 | * |
||
444 | * @deprecated |
||
445 | * |
||
446 | * @return mixed the value of the form element. |
||
447 | */ |
||
448 | public function getValue() |
||
452 | |||
453 | |||
454 | |||
455 | /** |
||
456 | * Get the escaped value of the form element. |
||
457 | * |
||
458 | * @return mixed the value of the form element. |
||
459 | */ |
||
460 | 5 | public function getEscapedValue() |
|
464 | |||
465 | |||
466 | |||
467 | /** |
||
468 | * Get the unescaped value of the form element. |
||
469 | * |
||
470 | * @return mixed the value of the form element. |
||
471 | */ |
||
472 | 5 | public function getRawValue() |
|
476 | |||
477 | |||
478 | |||
479 | /** |
||
480 | * Get the value of the form element and respect configuration |
||
481 | * details whether it should be raw or escaped. |
||
482 | * |
||
483 | * @return mixed the value of the form element. |
||
484 | */ |
||
485 | public function value() |
||
495 | |||
496 | |||
497 | |||
498 | /** |
||
499 | * Get the escaped value of the form element and respect configuration |
||
500 | * details whether it should be raw or escaped. |
||
501 | * |
||
502 | * @return mixed the value of the form element. |
||
503 | */ |
||
504 | 1 | public function escValue() |
|
508 | |||
509 | |||
510 | |||
511 | /** |
||
512 | * Get the raw value of the form element. |
||
513 | * |
||
514 | * @return mixed the value of the form element. |
||
515 | */ |
||
516 | 1 | public function rawValue() |
|
520 | |||
521 | |||
522 | |||
523 | /** |
||
524 | * Set the value for the element. |
||
525 | * |
||
526 | * @param mixed $value set this to be the value of the formelement. |
||
527 | * |
||
528 | * @return mixed the value of the form element. |
||
529 | */ |
||
530 | 1 | public function setValue($value) |
|
534 | |||
535 | |||
536 | |||
537 | /** |
||
538 | * Get the status of the form element if it is checked or not. |
||
539 | * |
||
540 | * @return mixed the value of the form element. |
||
541 | */ |
||
542 | public function checked() |
||
546 | } |
||
547 |
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: