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 StatsJsonView 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 StatsJsonView, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 13 | |||
| 14 | /**  | 
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| 15 | * JSON response for requesting the stats data.  | 
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| 16 | *  | 
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| 17 | * @since 1.0  | 
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| 18 | */  | 
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| 19 | class StatsJsonView extends BaseJsonView  | 
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| 20 | { | 
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| 21 | /**  | 
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| 22 | * Flag if the response should return the raw data.  | 
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| 23 | *  | 
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| 24 | * @var boolean  | 
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| 25 | * @since 1.0  | 
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| 26 | */  | 
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| 27 | private $authorizedRaw = false;  | 
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| 28 | |||
| 29 | /**  | 
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| 30 | * Array holding the valid data sources.  | 
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| 31 | *  | 
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| 32 | * @var array  | 
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| 33 | * @since 1.0  | 
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| 34 | */  | 
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| 35 | private $dataSources = ['php_version', 'db_type', 'db_version', 'cms_version', 'server_os'];  | 
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| 36 | |||
| 37 | /**  | 
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| 38 | * The data source to return.  | 
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| 39 | *  | 
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| 40 | * @var string  | 
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| 41 | * @since 1.0  | 
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| 42 | */  | 
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| 43 | private $source = '';  | 
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| 44 | |||
| 45 | /**  | 
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| 46 | * Count of the number of items.  | 
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| 47 | *  | 
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| 48 | * @var integer  | 
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| 49 | * @since 1.0  | 
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| 50 | */  | 
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| 51 | private $totalItems = 0;  | 
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| 52 | |||
| 53 | /**  | 
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| 54 | * Instantiate the view.  | 
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| 55 | *  | 
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| 56 | * @param StatsModel $model The model object.  | 
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| 57 | *  | 
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| 58 | * @since 1.0  | 
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| 59 | */  | 
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| 60 | public function __construct(StatsModel $model)  | 
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| 64 | |||
| 65 | /**  | 
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| 66 | * Set whether the raw data should be returned.  | 
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| 67 | *  | 
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| 68 | * @param bool $authorizedRaw Flag if the response should return the raw data.  | 
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| 69 | *  | 
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| 70 | * @return void  | 
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| 71 | *  | 
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| 72 | * @since 1.0  | 
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| 73 | */  | 
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| 74 | 1 | public function isAuthorizedRaw(bool $authorizedRaw)  | 
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| 78 | |||
| 79 | /**  | 
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| 80 | * Method to render the view.  | 
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| 81 | *  | 
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| 82 | * @return string The rendered view.  | 
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| 83 | *  | 
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| 84 | * @since 1.0  | 
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| 85 | * @throws \InvalidArgumentException  | 
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| 86 | */  | 
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| 87 | public function render()  | 
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| 158 | |||
| 159 | /**  | 
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| 160 | * Set the data source.  | 
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| 161 | *  | 
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| 162 | * @param string $source Data source to return.  | 
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| 163 | *  | 
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| 164 | * @return void  | 
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| 165 | *  | 
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| 166 | * @since 1.0  | 
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| 167 | */  | 
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| 168 | 1 | public function setSource(string $source)  | 
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| 172 | |||
| 173 | /**  | 
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| 174 | * Process the raw data into the response data format.  | 
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| 175 | *  | 
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| 176 | * @param array $data The raw data array.  | 
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| 177 | *  | 
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| 178 | * @return array  | 
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| 179 | *  | 
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| 180 | * @since 1.0  | 
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| 181 | */  | 
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| 182 | private function buildResponseData(array $data) : array  | 
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| 209 | |||
| 210 | /**  | 
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| 211 | * Process the response for a single data source.  | 
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| 212 | *  | 
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| 213 | * @param \Generator $generator The source items to process.  | 
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| 214 | *  | 
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| 215 | * @return string The rendered view.  | 
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| 216 | *  | 
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| 217 | * @since 1.0  | 
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| 218 | */  | 
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| 219 | private function processSingleSource(\Generator $generator) : string  | 
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| 269 | |||
| 270 | /**  | 
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| 271 | * Sanitize the response data into summarized groups.  | 
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| 272 | *  | 
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| 273 | * @param array $responseData The response data to sanitize.  | 
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| 274 | *  | 
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| 275 | * @return array  | 
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| 276 | *  | 
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| 277 | * @since 1.0  | 
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| 278 | */  | 
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| 279 | private function sanitizeData(array $responseData) : array  | 
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| 280 | 	{ | 
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| 281 | foreach ($responseData as $key => $dataGroup)  | 
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| 282 | 		{ | 
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| 283 | switch ($key)  | 
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| 284 | 			{ | 
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| 285 | case 'php_version':  | 
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| 286 | case 'db_version':  | 
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| 287 | // We're going to group by minor version branch here and convert to a percentage  | 
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| 288 | $counts = [];  | 
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| 289 | |||
| 290 | foreach ($dataGroup as $row)  | 
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| 291 | 					{ | 
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| 292 | 						$exploded = explode('.', $row['name']); | 
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| 293 | $version = $exploded[0] . '.' . (isset($exploded[1]) ? $exploded[1] : '0');  | 
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| 294 | |||
| 295 | // If the container does not exist, add it  | 
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| 296 | if (!isset($counts[$version]))  | 
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| 297 | 						{ | 
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| 298 | $counts[$version] = 0;  | 
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| 299 | }  | 
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| 300 | |||
| 301 | $counts[$version] += $row['count'];  | 
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| 302 | }  | 
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| 303 | |||
| 304 | $sanitizedData = [];  | 
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| 305 | |||
| 306 | View Code Duplication | foreach ($counts as $version => $count)  | 
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| 307 | 					{ | 
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| 308 | $sanitizedData[$version] = round(($count / $this->totalItems) * 100, 2);  | 
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| 309 | }  | 
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| 310 | |||
| 311 | $responseData[$key] = $sanitizedData;  | 
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| 312 | |||
| 313 | break;  | 
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| 314 | |||
| 315 | case 'server_os':  | 
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| 316 | // We're going to group by operating system here  | 
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| 317 | $counts = [];  | 
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| 318 | |||
| 319 | foreach ($dataGroup as $row)  | 
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| 320 | 					{ | 
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| 321 | 						$fullOs = explode(' ', $row['name']); | 
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| 322 | $os = $fullOs[0];  | 
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| 323 | |||
| 324 | // If the container does not exist, add it  | 
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| 325 | if (!isset($counts[$os]))  | 
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| 326 | 						{ | 
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| 327 | $counts[$os] = 0;  | 
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| 328 | }  | 
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| 329 | |||
| 330 | $counts[$os] += $row['count'];  | 
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| 331 | }  | 
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| 332 | |||
| 333 | $sanitizedData = [];  | 
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| 334 | |||
| 335 | View Code Duplication | foreach ($counts as $os => $count)  | 
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| 336 | 					{ | 
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| 337 | $sanitizedData[$os] = round(($count / $this->totalItems) * 100, 2);  | 
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| 338 | }  | 
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| 339 | |||
| 340 | $responseData[$key] = $sanitizedData;  | 
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| 341 | |||
| 342 | break;  | 
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| 343 | |||
| 344 | case 'db_type':  | 
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| 345 | case 'cms_version':  | 
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| 346 | default:  | 
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| 347 | // For now, group by the object name and figure out the percentages  | 
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| 348 | $sanitizedData = [];  | 
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| 349 | |||
| 350 | foreach ($dataGroup as $row)  | 
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| 351 | 					{ | 
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| 352 | $sanitizedData[$row['name']] = round(($row['count'] / $this->totalItems) * 100, 2);  | 
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| 353 | }  | 
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| 354 | |||
| 355 | $responseData[$key] = $sanitizedData;  | 
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| 356 | |||
| 357 | break;  | 
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| 358 | }  | 
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| 364 | 
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: