Complex classes like Container 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 Container, and based on these observations, apply Extract Interface, too.
| 1 | <?php | ||
| 31 | abstract class Container extends \Nette\Application\UI\Control | ||
| 32 | { | ||
| 33 | /** @var bool */ | ||
| 34 | protected $hasColumns; | ||
| 35 | |||
| 36 | /** @var bool */ | ||
| 37 | protected $hasFilters; | ||
| 38 | |||
| 39 | /** @var bool */ | ||
| 40 | protected $hasActions; | ||
| 41 | |||
| 42 | /** @var bool */ | ||
| 43 | protected $hasOperation; | ||
| 44 | |||
| 45 | /** @var bool */ | ||
| 46 | protected $hasExport; | ||
| 47 | |||
| 48 | 1 | /** | |
| 49 | * Returns column component. | ||
| 50 | * @param string $name | ||
| 51 | 1 | * @param bool $need | |
| 52 | * @return Editable | ||
| 53 | */ | ||
| 54 | 1 | public function getColumn($name, $need = TRUE) | |
| 60 | |||
| 61 | /** | ||
| 62 | * Returns filter component. | ||
| 63 | * @param string $name | ||
| 64 | * @param bool $need | ||
| 65 | * @return Filter | ||
| 66 | */ | ||
| 67 | 1 | public function getFilter($name, $need = TRUE) | |
| 73 | |||
| 74 | /** | ||
| 75 | * Returns action component. | ||
| 76 | * @param string $name | ||
| 77 | * @param bool $need | ||
| 78 | * @return Action | ||
| 79 | */ | ||
| 80 | 1 | public function getAction($name, $need = TRUE) | |
| 86 | |||
| 87 | /** | ||
| 88 | * Returns operations component. | ||
| 89 | * @param bool $need | ||
| 90 | * @return Operation | ||
| 91 | */ | ||
| 92 | 1 | public function getOperation($need = TRUE) | |
| 96 | |||
| 97 | /** | ||
| 98 | * Returns export component. | ||
| 99 | * @param string $name | ||
| 100 | * @param bool $need | ||
| 101 | * @return CsvExport | ||
| 102 | 1 | */ | |
| 103 | public function getExport($name = NULL, $need = TRUE) | ||
| 118 | 1 | ||
| 119 | 1 | /** | |
| 120 | 1 | * @param bool $need | |
| 121 | * @return BaseExport[] | ||
| 122 | 1 | */ | |
| 123 | public function getExports($need = TRUE) | ||
| 131 | |||
| 132 | 1 | /**********************************************************************************************/ | |
| 133 | |||
| 134 | 1 | /** | |
| 135 | 1 | * @param bool $useCache | |
| 136 | 1 | * @return bool | |
| 137 | 1 | * @internal | |
| 138 | 1 | */ | |
| 139 | public function hasColumns($useCache = TRUE) | ||
| 151 | |||
| 152 | 1 | /** | |
| 153 | 1 | * @param bool $useCache | |
| 154 | 1 | * @return bool | |
| 155 | 1 | * @internal | |
| 156 | 1 | */ | |
| 157 | public function hasFilters($useCache = TRUE) | ||
| 169 | |||
| 170 | 1 | /** | |
| 171 | 1 | * @param bool $useCache | |
| 172 | 1 | * @return bool | |
| 173 | 1 | * @internal | |
| 174 | */ | ||
| 175 | 1 | public function hasActions($useCache = TRUE) | |
| 187 | 1 | ||
| 188 | 1 | /** | |
| 189 | 1 | * @param bool $useCache | |
| 190 | 1 | * @return bool | |
| 191 | * @internal | ||
| 192 | 1 | */ | |
| 193 | public function hasOperation($useCache = TRUE) | ||
| 204 | 1 | ||
| 205 | /** | ||
| 206 | * @param bool $useCache | ||
| 207 | * @return bool | ||
| 208 | * @internal | ||
| 209 | */ | ||
| 210 | public function hasExport($useCache = TRUE) | ||
| 221 | |||
| 222 | /**********************************************************************************************/ | ||
| 223 | |||
| 224 | 1 | /** | |
| 225 | * @param string $name | ||
| 226 | * @param string $label | ||
| 227 | * @return Columns\Text | ||
| 228 | */ | ||
| 229 | public function addColumnText($name, $label) | ||
| 233 | |||
| 234 | /** | ||
| 235 | 1 | * @param string $name | |
| 236 | * @param string $label | ||
| 237 | * @return Columns\Email | ||
| 238 | */ | ||
| 239 | public function addColumnEmail($name, $label) | ||
| 243 | |||
| 244 | /** | ||
| 245 | * @param string $name | ||
| 246 | * @param string $label | ||
| 247 | * @return Columns\Link | ||
| 248 | 1 | */ | |
| 249 | public function addColumnLink($name, $label) | ||
| 253 | |||
| 254 | /** | ||
| 255 | * @param string $name | ||
| 256 | * @param string $label | ||
| 257 | * @param string $dateFormat | ||
| 258 | * @return Columns\Date | ||
| 259 | */ | ||
| 260 | 1 | public function addColumnDate($name, $label, $dateFormat = NULL) | |
| 264 | |||
| 265 | /** | ||
| 266 | * @param string $name | ||
| 267 | * @param string $label | ||
| 268 | * @param int $decimals number of decimal points | ||
| 269 | * @param string $decPoint separator for the decimal point | ||
| 270 | 1 | * @param string $thousandsSep thousands separator | |
| 271 | * @return Columns\Number | ||
| 272 | */ | ||
| 273 | public function addColumnNumber($name, $label, $decimals = NULL, $decPoint = NULL, $thousandsSep = NULL) | ||
| 277 | |||
| 278 | /**********************************************************************************************/ | ||
| 279 | |||
| 280 | 1 | /** | |
| 281 | * @param string $name | ||
| 282 | * @param string $label | ||
| 283 | * @return Filters\Text | ||
| 284 | */ | ||
| 285 | public function addFilterText($name, $label) | ||
| 289 | |||
| 290 | 1 | /** | |
| 291 | * @param string $name | ||
| 292 | * @param string $label | ||
| 293 | * @return Filters\Date | ||
| 294 | */ | ||
| 295 | public function addFilterDate($name, $label) | ||
| 299 | |||
| 300 | /** | ||
| 301 | 1 | * @param string $name | |
| 302 | * @param string $label | ||
| 303 | * @return Filters\DateRange | ||
| 304 | */ | ||
| 305 | public function addFilterDateRange($name, $label) | ||
| 309 | |||
| 310 | /** | ||
| 311 | 1 | * @param string $name | |
| 312 | * @param string $label | ||
| 313 | * @return Filters\Check | ||
| 314 | */ | ||
| 315 | public function addFilterCheck($name, $label) | ||
| 319 | |||
| 320 | /** | ||
| 321 | 1 | * @param string $name | |
| 322 | * @param string $label | ||
| 323 | * @param array $items | ||
| 324 | * @return Filters\Select | ||
| 325 | */ | ||
| 326 | public function addFilterSelect($name, $label, array $items = NULL) | ||
| 330 | |||
| 331 | /** | ||
| 332 | * @param string $name | ||
| 333 | * @param string $label | ||
| 334 | * @return Filters\Number | ||
| 335 | 1 | */ | |
| 336 | public function addFilterNumber($name, $label) | ||
| 340 | |||
| 341 | /** | ||
| 342 | * @param string $name | ||
| 343 | * @param \Nette\Forms\IControl $formControl | ||
| 344 | * @return Filters\Custom | ||
| 345 | */ | ||
| 346 | 1 | public function addFilterCustom($name, \Nette\Forms\IControl $formControl) | |
| 350 | |||
| 351 | /**********************************************************************************************/ | ||
| 352 | |||
| 353 | /** | ||
| 354 | * @param string $name | ||
| 355 | * @param string $label | ||
| 356 | * @param string $destination | ||
| 357 | * @param array $arguments | ||
| 358 | 1 | * @return Actions\Href | |
| 359 | */ | ||
| 360 | public function addActionHref($name, $label, $destination = NULL, array $arguments = []) | ||
| 364 | |||
| 365 | /** | ||
| 366 | * @param string $name | ||
| 367 | 1 | * @param string $label | |
| 368 | * @param callback $onClick | ||
| 369 | * @return Actions\Event | ||
| 370 | */ | ||
| 371 | public function addActionEvent($name, $label, $onClick = NULL) | ||
| 375 | |||
| 376 | /**********************************************************************************************/ | ||
| 377 | |||
| 378 | 1 | /** | |
| 379 | 1 | * @param array $operations | |
| 380 | * @param callback $onSubmit - callback after operation submit | ||
| 381 | * @return Operation | ||
| 382 | */ | ||
| 383 | 1 | public function setOperation(array $operations, $onSubmit) | |
| 387 | 1 | ||
| 388 | 1 | /** | |
| 389 | * @param string $label of exporting file | ||
| 390 | 1 | * @return Export | |
| 391 | * | ||
| 392 | * @deprecated | ||
| 393 | 1 | */ | |
| 394 | public function setExport($label = NULL) | ||
| 399 | |||
| 400 | /** | ||
| 401 | * @param BaseExport $export | ||
| 402 | * @param string $name Component name | ||
| 403 | * @return BaseExport | ||
| 404 | */ | ||
| 405 | public function addExport(BaseExport $export, $name) | ||
| 415 | |||
| 416 | /** | ||
| 417 | * Sets all columns as editable. | ||
| 418 | * First parameter is optional and is for implementation of method for saving modified data. | ||
| 419 |      * @param callback $callback function($id, $newValue, $oldValue, Editable $column) {} | ||
| 420 | * @return Grid | ||
| 421 | */ | ||
| 422 | public function setEditableColumns($callback = NULL) | ||
| 438 | } | ||
| 439 | 
Let’s take a look at an example:
In the above example, the authenticate() method works fine as long as you just pass instances of MyUser. However, if you now also want to pass a different implementation of User which does not have a getDisplayName() method, the code will break.
Available Fixes
Change the type-hint for the parameter:
Add an additional type-check:
Add the method to the interface: