Complex classes like QueryBuilderEngine 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 QueryBuilderEngine, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
||
| 16 | class QueryBuilderEngine extends BaseEngine |
||
| 17 | { |
||
| 18 | /** |
||
| 19 | * Builder object. |
||
| 20 | * |
||
| 21 | * @var \Illuminate\Database\Query\Builder |
||
| 22 | */ |
||
| 23 | protected $query; |
||
| 24 | |||
| 25 | /** |
||
| 26 | * Database connection used. |
||
| 27 | * |
||
| 28 | * @var \Illuminate\Database\Connection |
||
| 29 | */ |
||
| 30 | protected $connection; |
||
| 31 | |||
| 32 | /** |
||
| 33 | * @param \Illuminate\Database\Query\Builder $builder |
||
| 34 | */ |
||
| 35 | public function __construct(Builder $builder) |
||
| 36 | { |
||
| 37 | $this->query = $builder; |
||
| 38 | $this->request = resolve('datatables.request'); |
||
| 39 | $this->config = resolve('datatables.config'); |
||
| 40 | $this->columns = $builder->columns; |
||
| 41 | $this->connection = $builder->getConnection(); |
||
| 42 | if ($this->config->isDebugging()) { |
||
| 43 | $this->connection->enableQueryLog(); |
||
| 44 | } |
||
| 45 | } |
||
| 46 | |||
| 47 | /** |
||
| 48 | * Set auto filter off and run your own filter. |
||
| 49 | * Overrides global search. |
||
| 50 | * |
||
| 51 | * @param callable $callback |
||
| 52 | * @param bool $globalSearch |
||
| 53 | * @return $this |
||
| 54 | */ |
||
| 55 | public function filter(callable $callback, $globalSearch = false) |
||
| 56 | { |
||
| 57 | $this->overrideGlobalSearch($callback, $this->query, $globalSearch); |
||
| 58 | |||
| 59 | return $this; |
||
| 60 | } |
||
| 61 | |||
| 62 | /** |
||
| 63 | * Organizes works. |
||
| 64 | * |
||
| 65 | * @param bool $mDataSupport |
||
| 66 | * @return \Illuminate\Http\JsonResponse |
||
| 67 | * @throws \Exception |
||
| 68 | */ |
||
| 69 | public function make($mDataSupport = false) |
||
| 70 | { |
||
| 71 | try { |
||
| 72 | $this->totalRecords = $this->totalCount(); |
||
| 73 | |||
| 74 | if ($this->totalRecords) { |
||
| 75 | $this->filterRecords(); |
||
| 76 | $this->ordering(); |
||
| 77 | $this->paginate(); |
||
| 78 | } |
||
| 79 | |||
| 80 | $data = $this->transform($this->getProcessedData($mDataSupport)); |
||
| 81 | |||
| 82 | return $this->render($data); |
||
| 83 | } catch (\Exception $exception) { |
||
| 84 | return $this->errorResponse($exception); |
||
| 85 | } |
||
| 86 | } |
||
| 87 | |||
| 88 | /** |
||
| 89 | * Count total items. |
||
| 90 | * |
||
| 91 | * @return integer |
||
| 92 | */ |
||
| 93 | public function totalCount() |
||
| 97 | |||
| 98 | /** |
||
| 99 | * Counts current query. |
||
| 100 | * |
||
| 101 | * @return int |
||
| 102 | */ |
||
| 103 | public function count() |
||
| 112 | |||
| 113 | /** |
||
| 114 | * Prepare count query builder. |
||
| 115 | * |
||
| 116 | * @return \Illuminate\Database\Query\Builder |
||
| 117 | */ |
||
| 118 | protected function prepareCountQuery() |
||
| 129 | |||
| 130 | /** |
||
| 131 | * Check if builder query uses complex sql. |
||
| 132 | * |
||
| 133 | * @param \Illuminate\Database\Query\Builder $builder |
||
| 134 | * @return bool |
||
| 135 | */ |
||
| 136 | protected function isComplexQuery($builder) |
||
| 140 | |||
| 141 | /** |
||
| 142 | * Wrap column with DB grammar. |
||
| 143 | * |
||
| 144 | * @param string $column |
||
| 145 | * @return string |
||
| 146 | */ |
||
| 147 | protected function wrap($column) |
||
| 151 | |||
| 152 | /** |
||
| 153 | * Perform sorting of columns. |
||
| 154 | * |
||
| 155 | * @return void |
||
| 156 | */ |
||
| 157 | public function ordering() |
||
| 185 | |||
| 186 | /** |
||
| 187 | * Get the base query builder instance. |
||
| 188 | * |
||
| 189 | * @param mixed $instance |
||
| 190 | * @return \Illuminate\Database\Query\Builder |
||
| 191 | */ |
||
| 192 | protected function getBaseQueryBuilder($instance = null) |
||
| 204 | |||
| 205 | /** |
||
| 206 | * Check if column has custom sort handler. |
||
| 207 | * |
||
| 208 | * @param string $column |
||
| 209 | * @return bool |
||
| 210 | */ |
||
| 211 | protected function hasCustomOrder($column) |
||
| 215 | |||
| 216 | /** |
||
| 217 | * Apply orderColumn custom query. |
||
| 218 | * |
||
| 219 | * @param string $column |
||
| 220 | * @param array $orderable |
||
| 221 | */ |
||
| 222 | protected function applyOrderColumn($column, $orderable): void |
||
| 229 | |||
| 230 | /** |
||
| 231 | * Resolve the proper column name be used. |
||
| 232 | * |
||
| 233 | * @param string $column |
||
| 234 | * @return string |
||
| 235 | */ |
||
| 236 | protected function resolveOrderByColumn($column) |
||
| 240 | |||
| 241 | /** |
||
| 242 | * Get NULLS LAST SQL. |
||
| 243 | * |
||
| 244 | * @param string $column |
||
| 245 | * @param string $direction |
||
| 246 | * @return string |
||
| 247 | */ |
||
| 248 | protected function getNullsLastSql($column, $direction) |
||
| 254 | |||
| 255 | /** |
||
| 256 | * Perform column search. |
||
| 257 | * |
||
| 258 | * @return void |
||
| 259 | */ |
||
| 260 | public function columnSearch() |
||
| 292 | |||
| 293 | /** |
||
| 294 | * Check if column has custom filter handler. |
||
| 295 | * |
||
| 296 | * @param string $columnName |
||
| 297 | * @return bool |
||
| 298 | */ |
||
| 299 | public function hasCustomFilter($columnName) |
||
| 303 | |||
| 304 | /** |
||
| 305 | * Get column keyword to use for search. |
||
| 306 | * |
||
| 307 | * @param int $i |
||
| 308 | * @param bool $raw |
||
| 309 | * @return string |
||
| 310 | */ |
||
| 311 | protected function getColumnSearchKeyword($i, $raw = false) |
||
| 320 | |||
| 321 | /** |
||
| 322 | * Apply filterColumn api search. |
||
| 323 | * |
||
| 324 | * @param mixed $query |
||
| 325 | * @param string $columnName |
||
| 326 | * @param string $keyword |
||
| 327 | * @param string $boolean |
||
| 328 | */ |
||
| 329 | protected function applyFilterColumn($query, $columnName, $keyword, $boolean = 'and') |
||
| 336 | |||
| 337 | /** |
||
| 338 | * Get eager loads keys if eloquent. |
||
| 339 | * |
||
| 340 | * @return array |
||
| 341 | */ |
||
| 342 | protected function getEagerLoads() |
||
| 350 | |||
| 351 | /** |
||
| 352 | * Compile queries for column search. |
||
| 353 | * |
||
| 354 | * @param int $i |
||
| 355 | * @param string $column |
||
| 356 | * @param string $keyword |
||
| 357 | */ |
||
| 358 | protected function compileColumnSearch($i, $column, $keyword) |
||
| 367 | |||
| 368 | /** |
||
| 369 | * Compile regex query column search. |
||
| 370 | * |
||
| 371 | * @param mixed $column |
||
| 372 | * @param string $keyword |
||
| 373 | */ |
||
| 374 | protected function regexColumnSearch($column, $keyword) |
||
| 394 | |||
| 395 | /** |
||
| 396 | * Compile query builder where clause depending on configurations. |
||
| 397 | * |
||
| 398 | * @param mixed $query |
||
| 399 | * @param string $column |
||
| 400 | * @param string $keyword |
||
| 401 | * @param string $relation |
||
| 402 | */ |
||
| 403 | protected function compileQuerySearch($query, $column, $keyword, $relation = 'or') |
||
| 415 | |||
| 416 | /** |
||
| 417 | * Patch for fix about ambiguous field. |
||
| 418 | * Ambiguous field error will appear when query use join table and search with keyword. |
||
| 419 | * |
||
| 420 | * @param mixed $query |
||
| 421 | * @param string $column |
||
| 422 | * @return string |
||
| 423 | */ |
||
| 424 | protected function addTablePrefix($query, $column) |
||
| 435 | |||
| 436 | /** |
||
| 437 | * Wrap a column and cast based on database driver. |
||
| 438 | * |
||
| 439 | * @param string $column |
||
| 440 | * @return string |
||
| 441 | */ |
||
| 442 | protected function castColumn($column) |
||
| 453 | |||
| 454 | /** |
||
| 455 | * Prepare search keyword based on configurations. |
||
| 456 | * |
||
| 457 | * @param string $keyword |
||
| 458 | * @return string |
||
| 459 | */ |
||
| 460 | protected function prepareKeyword($keyword) |
||
| 476 | |||
| 477 | /** |
||
| 478 | * Perform pagination. |
||
| 479 | * |
||
| 480 | * @return void |
||
| 481 | */ |
||
| 482 | public function paging() |
||
| 487 | |||
| 488 | /** |
||
| 489 | * Get paginated results. |
||
| 490 | * |
||
| 491 | * @return \Illuminate\Support\Collection |
||
| 492 | */ |
||
| 493 | public function results() |
||
| 497 | |||
| 498 | /** |
||
| 499 | * Add column in collection. |
||
| 500 | * |
||
| 501 | * @param string $name |
||
| 502 | * @param string|callable $content |
||
| 503 | * @param bool|int $order |
||
| 504 | * @return \Yajra\Datatables\Engines\BaseEngine|\Yajra\Datatables\Engines\QueryBuilderEngine |
||
| 505 | */ |
||
| 506 | public function addColumn($name, $content, $order = false) |
||
| 512 | |||
| 513 | /** |
||
| 514 | * Get query builder instance. |
||
| 515 | * |
||
| 516 | * @return \Illuminate\Database\Eloquent\Builder|\Illuminate\Database\Query\Builder |
||
| 517 | */ |
||
| 518 | public function getQuery() |
||
| 522 | |||
| 523 | /** |
||
| 524 | * Perform global search for the given keyword. |
||
| 525 | * |
||
| 526 | * @param string $keyword |
||
| 527 | */ |
||
| 528 | protected function globalSearch($keyword) |
||
| 551 | |||
| 552 | /** |
||
| 553 | * Append debug parameters on output. |
||
| 554 | * |
||
| 555 | * @param array $output |
||
| 556 | * @return array |
||
| 557 | */ |
||
| 558 | protected function showDebugger(array $output) |
||
| 565 | } |
||
| 566 |
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 sub-classes 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 parent class: