Complex classes like BaseCollection 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 BaseCollection, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 11 | class BaseCollection implements \Iterator, \ArrayAccess, \Countable { |
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| 12 | |||
| 13 | /** |
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| 14 | * @var int |
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| 15 | */ |
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| 16 | protected $position = 0; |
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| 17 | |||
| 18 | /** |
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| 19 | * Array of objects |
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| 20 | * |
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| 21 | * @var array |
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| 22 | */ |
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| 23 | protected $items = []; |
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| 24 | |||
| 25 | |||
| 26 | /** |
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| 27 | * @param array $items |
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| 28 | */ |
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| 29 | public function __construct(array $items = []) { |
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| 36 | |||
| 37 | |||
| 38 | /** |
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| 39 | * |
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| 40 | */ |
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| 41 | public function __clone() { |
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| 48 | |||
| 49 | |||
| 50 | /** |
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| 51 | * Return number of items in this collection |
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| 52 | * |
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| 53 | * @return int |
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| 54 | */ |
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| 55 | public function count() { |
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| 58 | |||
| 59 | |||
| 60 | /** |
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| 61 | * Add one item to begin of collection |
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| 62 | * This item is accessible via `$collection->getFirst();` |
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| 63 | * |
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| 64 | * @param $item |
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| 65 | * @return $this |
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| 66 | */ |
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| 67 | public function prepend($item) { |
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| 72 | |||
| 73 | |||
| 74 | /** |
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| 75 | * Add one item to the end of collection |
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| 76 | * This item is accessible via `$collection->getLast();` |
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| 77 | * |
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| 78 | * @param $item |
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| 79 | * @return $this |
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| 80 | */ |
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| 81 | public function append($item) { |
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| 87 | |||
| 88 | |||
| 89 | /** |
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| 90 | * @param int $index |
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| 91 | * @param array $items |
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| 92 | * @return $this |
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| 93 | * @throws \InvalidArgumentException |
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| 94 | */ |
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| 95 | public function addAfter($index, $items) { |
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| 112 | |||
| 113 | |||
| 114 | /** |
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| 115 | * Truncate current list of items and add new |
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| 116 | * |
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| 117 | * @param array $items |
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| 118 | * @return $this |
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| 119 | */ |
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| 120 | public function setItems($items) { |
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| 133 | |||
| 134 | |||
| 135 | /** |
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| 136 | * Remove part of items from collection |
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| 137 | * Works as array_slice |
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| 138 | * |
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| 139 | * |
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| 140 | * @param $offset |
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| 141 | * @param null $length |
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| 142 | * @return $this |
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| 143 | */ |
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| 144 | public function slice($offset, $length = null) { |
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| 148 | |||
| 149 | |||
| 150 | /** |
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| 151 | * Take part of items and return new collection |
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| 152 | * Works as array_slice |
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| 153 | * At this point items in 2 collection is same |
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| 154 | * |
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| 155 | * @param int $offset |
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| 156 | * @param null $length |
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| 157 | * @return self |
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| 158 | */ |
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| 159 | public function extractItems($offset, $length = null) { |
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| 167 | |||
| 168 | |||
| 169 | /** |
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| 170 | * Rewind current collection |
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| 171 | */ |
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| 172 | public function rewind() { |
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| 176 | |||
| 177 | |||
| 178 | /** |
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| 179 | * Return last item from collection |
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| 180 | * |
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| 181 | * @return mixed |
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| 182 | */ |
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| 183 | public function getLast() { |
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| 186 | |||
| 187 | |||
| 188 | /** |
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| 189 | * Return first item from collection |
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| 190 | * @return mixed |
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| 191 | */ |
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| 192 | public function getFirst() { |
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| 195 | |||
| 196 | |||
| 197 | /** |
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| 198 | * Return next item from current |
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| 199 | * Also can return item with position from current + $step |
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| 200 | * |
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| 201 | * @param int $step |
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| 202 | * @return mixed |
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| 203 | */ |
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| 204 | public function getNext($step = 1) { |
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| 208 | |||
| 209 | |||
| 210 | /** |
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| 211 | * Return previous item |
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| 212 | * Also can return previous from current position + $step |
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| 213 | * |
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| 214 | * @param int $step |
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| 215 | * @return mixed |
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| 216 | */ |
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| 217 | public function getPrevious($step = 1) { |
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| 221 | |||
| 222 | |||
| 223 | /** |
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| 224 | * Return current item in collection |
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| 225 | * |
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| 226 | * @return object |
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| 227 | */ |
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| 228 | public function current() { |
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| 231 | |||
| 232 | |||
| 233 | /** |
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| 234 | * Return current position |
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| 235 | * |
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| 236 | * @return int |
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| 237 | */ |
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| 238 | public function key() { |
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| 241 | |||
| 242 | |||
| 243 | /** |
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| 244 | * Switch to next position |
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| 245 | */ |
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| 246 | public function next() { |
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| 249 | |||
| 250 | |||
| 251 | /** |
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| 252 | * Check if item exist in current position |
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| 253 | * |
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| 254 | * @return bool |
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| 255 | */ |
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| 256 | public function valid() { |
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| 259 | |||
| 260 | |||
| 261 | /** |
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| 262 | * Add item to the end or modify item with given key |
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| 263 | * |
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| 264 | * @param int|null $offset |
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| 265 | * @param object $item |
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| 266 | * @return $this |
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| 267 | */ |
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| 268 | public function offsetSet($offset, $item) { |
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| 280 | |||
| 281 | |||
| 282 | /** |
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| 283 | * Check if item with given offset exists |
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| 284 | * |
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| 285 | * @param mixed $offset |
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| 286 | * @return bool |
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| 287 | */ |
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| 288 | public function offsetExists($offset) { |
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| 291 | |||
| 292 | |||
| 293 | /** |
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| 294 | * Remove item from collection |
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| 295 | * |
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| 296 | * @param int $offset |
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| 297 | */ |
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| 298 | public function offsetUnset($offset) { |
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| 301 | |||
| 302 | |||
| 303 | /** |
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| 304 | * Get item from collection |
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| 305 | * |
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| 306 | * @param int $offset |
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| 307 | * @return object |
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| 308 | */ |
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| 309 | public function offsetGet($offset) { |
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| 312 | |||
| 313 | |||
| 314 | /** |
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| 315 | * Return array of items connected to this collection |
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| 316 | * |
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| 317 | * Rewrite this method in you class |
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| 318 | * |
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| 319 | * <code> |
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| 320 | * foreach($collection->getItems() as $item){ |
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| 321 | * echo get_class($item)."\n; |
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| 322 | * } |
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| 323 | * </code> |
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| 324 | * @return object[] |
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| 325 | */ |
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| 326 | public function getItems() { |
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| 329 | |||
| 330 | |||
| 331 | /** |
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| 332 | * Iterate over objects in collection |
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| 333 | * |
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| 334 | * <code> |
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| 335 | * $collection->map(function($item, $index, $collection){ |
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| 336 | * if ( $index > 0 ) { |
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| 337 | * $item->remove(); |
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| 338 | * } |
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| 339 | * }) |
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| 340 | * </code> |
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| 341 | * |
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| 342 | * @param callback $callback |
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| 343 | * @return $this |
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| 344 | * @throws \InvalidArgumentException |
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| 345 | */ |
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| 346 | public function map($callback) { |
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| 360 | |||
| 361 | |||
| 362 | /** |
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| 363 | * @param int $index |
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| 364 | */ |
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| 365 | protected function validateIndex($index) { |
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| 370 | |||
| 371 | |||
| 372 | public function validateType($item) { |
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| 377 | |||
| 378 | } |