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:
| 1 | <?php | ||
| 17 | class DataItem implements | ||
| 18 | \ArrayAccess, | ||
| 19 | TwigDocumentInterface, | ||
| 20 | JailedDocumentInterface | ||
| 21 | { | ||
| 22 | protected $data; | ||
| 23 | |||
| 24 | private $fileExtension; | ||
| 25 | private $namespace; | ||
| 26 | private $fileName; | ||
| 27 | private $filePath; | ||
| 28 | private $fs; | ||
|  | |||
| 29 | |||
| 30 | public function __construct($filePath) | ||
| 46 | |||
| 47 | /// | ||
| 48 | // Jailed Document implementation | ||
| 49 | /// | ||
| 50 | |||
| 51 | /** | ||
| 52 |      * {@inheritdoc} | ||
| 53 | */ | ||
| 54 | public function createJail() | ||
| 60 | |||
| 61 | /// | ||
| 62 | // ArrayAccess implementation | ||
| 63 | /// | ||
| 64 | |||
| 65 | /** | ||
| 66 |      * {@inheritdoc} | ||
| 67 | */ | ||
| 68 | public function offsetExists($offset) | ||
| 72 | |||
| 73 | /** | ||
| 74 |      * {@inheritdoc} | ||
| 75 | */ | ||
| 76 | public function offsetGet($offset) | ||
| 80 | |||
| 81 | /** | ||
| 82 |      * {@inheritdoc} | ||
| 83 | */ | ||
| 84 | public function offsetSet($offset, $value) | ||
| 88 | |||
| 89 | /** | ||
| 90 |      * {@inheritdoc} | ||
| 91 | */ | ||
| 92 | public function offsetUnset($offset) | ||
| 96 | |||
| 97 | /// | ||
| 98 | // Twig Document implementation | ||
| 99 | /// | ||
| 100 | |||
| 101 | public function getNamespace() | ||
| 105 | |||
| 106 | public function setNamespace($namespace) | ||
| 110 | |||
| 111 | public function getExtension() | ||
| 115 | |||
| 116 | public function getFilePath() | ||
| 120 | |||
| 121 | public function getName() | ||
| 125 | |||
| 126 | public function getRelativeFilePath() | ||
| 136 | |||
| 137 | public function refreshFileContent() | ||
| 157 | |||
| 158 | /// | ||
| 159 | // File parsing helpers | ||
| 160 | /// | ||
| 161 | |||
| 162 | /** | ||
| 163 | * Convert from CSV into an associative array. | ||
| 164 | * | ||
| 165 | * @param string $content CSV formatted text | ||
| 166 | * | ||
| 167 | * @return array | ||
| 168 | */ | ||
| 169 | private function fromCsv($content) | ||
| 182 | |||
| 183 | /** | ||
| 184 | * Convert from JSON into an associative array. | ||
| 185 | * | ||
| 186 | * @param string $content JSON formatted text | ||
| 187 | * | ||
| 188 | * @return array | ||
| 189 | */ | ||
| 190 | private function fromJson($content) | ||
| 194 | |||
| 195 | /** | ||
| 196 | * Convert from XML into an associative array. | ||
| 197 | * | ||
| 198 | * @param string $content XML formatted text | ||
| 199 | * | ||
| 200 | * @return array | ||
| 201 | */ | ||
| 202 | private function fromXml($content) | ||
| 206 | |||
| 207 | /** | ||
| 208 | * Convert from YAML into an associative array. | ||
| 209 | * | ||
| 210 | * @param string $content YAML formatted text | ||
| 211 | * | ||
| 212 | * @return array | ||
| 213 | */ | ||
| 214 | private function fromYaml($content) | ||
| 218 | |||
| 219 | /** | ||
| 220 | * An alias for handling `*.yml` files. | ||
| 221 | * | ||
| 222 | * @param string $content YAML formatted text | ||
| 223 | * | ||
| 224 | * @return array | ||
| 225 | */ | ||
| 226 | private function fromYml($content) | ||
| 230 | |||
| 231 | /** | ||
| 232 | * @param string $extension | ||
| 233 | * | ||
| 234 | * @todo 0.1.0 Create a help page on the main stakx website for this topic and link to it | ||
| 235 | * | ||
| 236 | * @throws DependencyMissingException | ||
| 237 | */ | ||
| 238 | private function handleDependencies($extension) | ||
| 245 | } | ||
| 246 | 
Short variable names may make your code harder to understand. Variable names should be self-descriptive. This check looks for variable names who are shorter than a configured minimum.