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 DisplayTabbed 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 DisplayTabbed, and based on these observations, apply Extract Interface, too.
| 1 | <?php | ||
| 18 | class DisplayTabbed implements DisplayInterface, FormInterface | ||
| 19 | { | ||
| 20 | use FormElements, VisibleCondition, \SleepingOwl\Admin\Traits\Renderable; | ||
| 21 | |||
| 22 | /** | ||
| 23 | * @var string | ||
| 24 | */ | ||
| 25 | protected $view = 'display.tabbed'; | ||
| 26 | |||
| 27 | /** | ||
| 28 | * DisplayTabbed constructor. | ||
| 29 | * | ||
| 30 | * @param Closure|TabInterface[] $tabs | ||
| 31 | */ | ||
| 32 | public function __construct($tabs = null) | ||
| 40 | |||
| 41 | /** | ||
| 42 | * Initialize tabbed interface. | ||
| 43 | */ | ||
| 44 | public function initialize() | ||
| 78 | |||
| 79 | /** | ||
| 80 | * @return Model $model|null | ||
| 81 | */ | ||
| 82 | public function getModel() | ||
| 90 | |||
| 91 | /** | ||
| 92 | * @param string $class | ||
| 93 | * | ||
| 94 | * @return $this | ||
| 95 | */ | ||
| 96 | public function setModelClass($class) | ||
| 106 | |||
| 107 | /** | ||
| 108 | * @return TabInterface[]|DisplayTabsCollection | ||
| 109 | */ | ||
| 110 | public function getTabs() | ||
| 114 | |||
| 115 | /** | ||
| 116 | * @param Closure|TabInterface[] $tabs | ||
| 117 | * | ||
| 118 | * @return $this | ||
| 119 | */ | ||
| 120 | public function setTabs($tabs) | ||
| 128 | |||
| 129 | /** | ||
| 130 | * @param array $elements | ||
| 131 | * | ||
| 132 | * @return $this | ||
| 133 | */ | ||
| 134 | public function setElements(array $elements) | ||
| 146 | |||
| 147 | /** | ||
| 148 | * @param Renderable $display | ||
| 149 | * @param string $label | ||
| 150 | * @param bool|false $active | ||
| 151 | * | ||
| 152 | * @return TabInterface | ||
| 153 | */ | ||
| 154 | public function appendTab(Renderable $display, $label, $active = false) | ||
| 162 | |||
| 163 | /** | ||
| 164 | * @param TabInterface $element | ||
| 165 | * | ||
| 166 | * @return $this | ||
| 167 | */ | ||
| 168 | public function addElement(TabInterface $element) | ||
| 174 | |||
| 175 | /** | ||
| 176 | * @param string $action | ||
| 177 | * | ||
| 178 | * @return $this | ||
| 179 | */ | ||
| 180 | public function setAction($action) | ||
| 190 | |||
| 191 | /** | ||
| 192 | * @param int $id | ||
| 193 | * | ||
| 194 | * @return $this | ||
| 195 | */ | ||
| 196 | public function setId($id) | ||
| 206 | |||
| 207 | /** | ||
| 208 | * @param \Illuminate\Http\Request $request | ||
| 209 | * @param ModelConfigurationInterface $model | ||
| 210 | * | ||
| 211 | * @return void | ||
| 212 | */ | ||
| 213 | View Code Duplication | public function validateForm(\Illuminate\Http\Request $request, ModelConfigurationInterface $model = null) | |
| 223 | |||
| 224 | /** | ||
| 225 | * @param \Illuminate\Http\Request $request | ||
| 226 | * @param ModelConfigurationInterface $model | ||
| 227 | * | ||
| 228 | * @return void | ||
| 229 | */ | ||
| 230 | View Code Duplication | public function saveForm(\Illuminate\Http\Request $request, ModelConfigurationInterface $model = null) | |
| 240 | |||
| 241 | /** | ||
| 242 | * @return null | ||
| 243 | */ | ||
| 244 | public function getValue() | ||
| 247 | |||
| 248 | /** | ||
| 249 | * @return bool | ||
| 250 | */ | ||
| 251 | public function isReadonly() | ||
| 255 | |||
| 256 | /** | ||
| 257 | * @return bool | ||
| 258 | */ | ||
| 259 | public function isValueSkipped() | ||
| 263 | |||
| 264 | /** | ||
| 265 | * @return array | ||
| 266 | */ | ||
| 267 | public function toArray() | ||
| 273 | |||
| 274 | /** | ||
| 275 | * Using in trait FormElements;. | ||
| 276 | * | ||
| 277 | * @param $object | ||
| 278 | * | ||
| 279 | * @return mixed | ||
| 280 | */ | ||
| 281 | protected function getElementContainer($object) | ||
| 285 | } | ||
| 286 | 
PHP has two types of connecting operators (logical operators, and boolean operators):
and&&or||The difference between these is the order in which they are executed. In most cases, you would want to use a boolean operator like
&&, or||.Let’s take a look at a few examples:
Logical Operators are used for Control-Flow
One case where you explicitly want to use logical operators is for control-flow such as this:
Since
dieintroduces problems of its own, f.e. it makes our code hardly testable, and prevents any kind of more sophisticated error handling; you probably do not want to use this in real-world code. Unfortunately, logical operators cannot be combined withthrowat this point:These limitations lead to logical operators rarely being of use in current PHP code.