Complex classes like TraversalTrait 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 TraversalTrait, and based on these observations, apply Extract Interface, too.
1 | <?php declare(strict_types=1); |
||
17 | trait TraversalTrait |
||
18 | { |
||
19 | /** |
||
20 | * @param iterable $nodes |
||
21 | * |
||
22 | * @return NodeList |
||
23 | */ |
||
24 | 138 | public function newNodeList(iterable $nodes = null): NodeList { |
|
36 | |||
37 | /** |
||
38 | * @param string $selector |
||
39 | * @param string $prefix |
||
40 | * |
||
41 | * @return NodeList |
||
42 | */ |
||
43 | 130 | public function find(string $selector, string $prefix = 'descendant::'): NodeList { |
|
48 | |||
49 | /** |
||
50 | * @param string $xpath |
||
51 | * |
||
52 | * @return NodeList |
||
53 | */ |
||
54 | 130 | public function findXPath(string $xpath): NodeList { |
|
71 | |||
72 | /** |
||
73 | * @param string|NodeList|\DOMNode|callable $input |
||
74 | * @param bool $matchType |
||
75 | * |
||
76 | * @return NodeList |
||
77 | */ |
||
78 | 18 | protected function getNodesMatchingInput($input, bool $matchType = true): NodeList { |
|
112 | |||
113 | /** |
||
114 | * @param string|NodeList|\DOMNode|callable $input |
||
115 | * |
||
116 | * @return bool |
||
117 | */ |
||
118 | 15 | public function is($input): bool { |
|
121 | |||
122 | /** |
||
123 | * @param string|NodeList|\DOMNode|callable $input |
||
124 | * |
||
125 | * @return NodeList |
||
126 | */ |
||
127 | 1 | public function not($input): NodeList { |
|
130 | |||
131 | /** |
||
132 | * @param string|NodeList|\DOMNode|callable $input |
||
133 | * |
||
134 | * @return NodeList |
||
135 | */ |
||
136 | 1 | public function filter($input): NodeList { |
|
139 | |||
140 | /** |
||
141 | * @param string|NodeList|\DOMNode|callable $input |
||
142 | * |
||
143 | * @return NodeList |
||
144 | */ |
||
145 | 1 | public function has($input): NodeList { |
|
177 | |||
178 | /** |
||
179 | * @param string|NodeList|\DOMNode|callable $selector |
||
180 | * |
||
181 | * @return \DOMNode|null |
||
182 | */ |
||
183 | public function preceding($selector = null): ?\DOMNode { |
||
186 | |||
187 | /** |
||
188 | * @param string|NodeList|\DOMNode|callable $selector |
||
189 | * |
||
190 | * @return NodeList |
||
191 | */ |
||
192 | 21 | public function precedingAll($selector = null): NodeList { |
|
195 | |||
196 | /** |
||
197 | * @param string|NodeList|\DOMNode|callable $input |
||
198 | * @param string|NodeList|\DOMNode|callable $selector |
||
199 | * |
||
200 | * @return NodeList |
||
201 | */ |
||
202 | 32 | public function precedingUntil($input = null, $selector = null): NodeList { |
|
205 | |||
206 | /** |
||
207 | * @param string|NodeList|\DOMNode|callable $selector |
||
208 | * |
||
209 | * @return \DOMNode|null |
||
210 | */ |
||
211 | 12 | public function following($selector = null): ?\DOMNode { |
|
214 | |||
215 | /** |
||
216 | * @param string|NodeList|\DOMNode|callable $selector |
||
217 | * |
||
218 | * @return NodeList |
||
219 | */ |
||
220 | 21 | public function followingAll($selector = null): NodeList { |
|
223 | |||
224 | /** |
||
225 | * @param string|NodeList|\DOMNode|callable $input |
||
226 | * @param string|NodeList|\DOMNode|callable $selector |
||
227 | * |
||
228 | * @return NodeList |
||
229 | */ |
||
230 | 25 | public function followingUntil($input = null, $selector = null): NodeList { |
|
233 | |||
234 | /** |
||
235 | * @param string|NodeList|\DOMNode|callable $selector |
||
236 | * |
||
237 | * @return NodeList |
||
238 | */ |
||
239 | public function siblings($selector = null): NodeList { |
||
250 | |||
251 | /** |
||
252 | * NodeList is only array like. Removing items using foreach() has undesired results. |
||
253 | * |
||
254 | * @return NodeList |
||
255 | */ |
||
256 | public function children(): NodeList { |
||
265 | |||
266 | /** |
||
267 | * @param string|NodeList|\DOMNode|callable $selector |
||
268 | * |
||
269 | * @return Element|NodeList|null |
||
270 | */ |
||
271 | 51 | public function parent($selector = null) { |
|
276 | |||
277 | /** |
||
278 | * @param int $index |
||
279 | * |
||
280 | * @return \DOMNode|null |
||
281 | */ |
||
282 | 2 | public function eq(int $index): ?\DOMNode { |
|
289 | |||
290 | /** |
||
291 | * @param string $selector |
||
292 | * |
||
293 | * @return NodeList |
||
294 | */ |
||
295 | public function parents(string $selector = null): NodeList { |
||
298 | |||
299 | /** |
||
300 | * @param string|NodeList|\DOMNode|callable $input |
||
301 | * @param string|NodeList|\DOMNode|callable $selector |
||
302 | * |
||
303 | * @return NodeList |
||
304 | */ |
||
305 | public function parentsUntil($input = null, $selector = null): NodeList { |
||
308 | |||
309 | /** |
||
310 | * @return \DOMNode |
||
311 | */ |
||
312 | public function intersect(): \DOMNode { |
||
331 | |||
332 | /** |
||
333 | * @param string|NodeList|\DOMNode|callable $input |
||
334 | * |
||
335 | * @return Element|NodeList|null |
||
336 | */ |
||
337 | 3 | public function closest($input) { |
|
342 | |||
343 | /** |
||
344 | * NodeList is only array like. Removing items using foreach() has undesired results. |
||
345 | * |
||
346 | * @return NodeList |
||
347 | */ |
||
348 | public function contents(): NodeList { |
||
359 | |||
360 | /** |
||
361 | * @param string|NodeList|\DOMNode $input |
||
362 | * |
||
363 | * @return NodeList |
||
364 | */ |
||
365 | public function add($input): NodeList { |
||
374 | |||
375 | /** @var int */ |
||
376 | private static $MATCH_TYPE_FIRST = 1; |
||
377 | |||
378 | /** @var int */ |
||
379 | private static $MATCH_TYPE_LAST = 2; |
||
380 | |||
381 | /** |
||
382 | * @param \DOMNode $baseNode |
||
383 | * @param string $property |
||
384 | * @param string|NodeList|\DOMNode|callable $input |
||
385 | * @param string|NodeList|\DOMNode|callable $selector |
||
386 | * @param int $matchType |
||
387 | * |
||
388 | * @return NodeList |
||
389 | */ |
||
390 | 65 | protected function _buildNodeListUntil(\DOMNode $baseNode, string $property, $input = null, $selector = null, int $matchType = null): NodeList { |
|
419 | |||
420 | /** |
||
421 | * @param iterable $nodeLists |
||
422 | * |
||
423 | * @return NodeList |
||
424 | */ |
||
425 | 65 | protected function _uniqueNodes(iterable $nodeLists): NodeList { |
|
442 | |||
443 | /** |
||
444 | * @param string $property |
||
445 | * @param string|NodeList|\DOMNode|callable $input |
||
446 | * @param string|NodeList|\DOMNode|callable $selector |
||
447 | * @param int $matchType |
||
448 | * |
||
449 | * @return NodeList |
||
450 | */ |
||
451 | 65 | protected function _walkPathUntil(string $property, $input = null, $selector = null, int $matchType = null): NodeList { |
|
460 | } |
This check looks for methods that are used by a trait but not required by it.
To illustrate, let’s look at the following code example
The trait
Idable
provides a methodequalsId
that in turn relies on the methodgetId()
. If this method does not exist on a class mixing in this trait, the method will fail.Adding the
getId()
as an abstract method to the trait will make sure it is available.