Complex classes like HierarchicalTrait 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 HierarchicalTrait, and based on these observations, apply Extract Interface, too.
1 | <?php |
||
14 | trait HierarchicalTrait |
||
15 | { |
||
16 | /** |
||
17 | * The object's parent, if any, in the hierarchy. |
||
18 | * |
||
19 | * @var string|integer|null |
||
20 | */ |
||
21 | protected $master; |
||
22 | |||
23 | /** |
||
24 | * Store a copy of the object's ancestry. |
||
25 | * |
||
26 | * @var HierarchicalInterface[]|null |
||
27 | */ |
||
28 | private $hierarchy = null; |
||
29 | |||
30 | /** |
||
31 | * Store a copy of the object's descendants. |
||
32 | * |
||
33 | * @var HierarchicalInterface[]|null |
||
34 | */ |
||
35 | private $children; |
||
36 | |||
37 | /** |
||
38 | * Store a copy of the object's siblings. |
||
39 | * |
||
40 | * @var HierarchicalInterface[]|null |
||
41 | */ |
||
42 | private $siblings; |
||
43 | |||
44 | /** |
||
45 | * The object's parent object, if any, in the hierarchy. |
||
46 | * |
||
47 | * @var HierarchicalInterface|null |
||
48 | */ |
||
49 | private $masterObject; |
||
50 | |||
51 | /** |
||
52 | * A store of cached objects. |
||
53 | * |
||
54 | * @var ModelInterface[] $objectCache |
||
55 | */ |
||
56 | public static $objectCache = []; |
||
57 | |||
58 | /** |
||
59 | * Reset this object's hierarchy. |
||
60 | * |
||
61 | * The object's hierarchy can be rebuilt with {@see self::hierarchy()}. |
||
62 | * |
||
63 | * @return HierarchicalInterface Chainable |
||
64 | */ |
||
65 | public function resetHierarchy() |
||
71 | |||
72 | /** |
||
73 | * Set this object's immediate parent. |
||
74 | * |
||
75 | * @param mixed $master The object's parent (or master). |
||
76 | * @return HierarchicalInterface Chainable |
||
77 | */ |
||
78 | public function setMaster($master) |
||
79 | { |
||
80 | $this->master = $master; |
||
81 | |||
82 | $this->resetHierarchy(); |
||
83 | |||
84 | return $this; |
||
85 | } |
||
86 | |||
87 | /** |
||
88 | * Retrieve this object's immediate parent. |
||
89 | * |
||
90 | * @return string|null |
||
91 | */ |
||
92 | public function getMaster() |
||
93 | { |
||
94 | return $this->master; |
||
95 | } |
||
96 | |||
97 | /** |
||
98 | * Retrieve this object's immediate parent as object. |
||
99 | * @return HierarchicalInterface|null |
||
100 | * @throws UnexpectedValueException The current object cannot be its own parent. |
||
101 | */ |
||
102 | public function getMasterObject() |
||
103 | { |
||
104 | if (!$this->masterObject && $this->hasMaster()) { |
||
105 | $master = $this->objFromIdent($this->getMaster()); |
||
106 | |||
107 | if ($master instanceof ModelInterface) { |
||
108 | if ($master->id() === $this->id()) { |
||
109 | throw new UnexpectedValueException(sprintf( |
||
110 | 'Can not be ones own parent: %s', |
||
111 | $master->id() |
||
112 | )); |
||
113 | } |
||
114 | } |
||
115 | |||
116 | $this->masterObject = $master; |
||
117 | } |
||
118 | |||
119 | return $this->masterObject; |
||
120 | } |
||
121 | |||
122 | /** |
||
123 | * Determine if this object has a direct parent. |
||
124 | * |
||
125 | * @return boolean |
||
126 | */ |
||
127 | public function hasMaster() |
||
131 | |||
132 | /** |
||
133 | * Determine if this object is the head (top-level) of its hierarchy. |
||
134 | * |
||
135 | * Top-level objects do not have a parent (master). |
||
136 | * |
||
137 | * @return boolean |
||
138 | */ |
||
139 | public function isTopLevel() |
||
143 | |||
144 | /** |
||
145 | * Determine if this object is the tail (last-level) of its hierarchy. |
||
146 | * |
||
147 | * Last-level objects do not have a children. |
||
148 | * |
||
149 | * @return boolean |
||
150 | */ |
||
151 | public function isLastLevel() |
||
155 | |||
156 | /** |
||
157 | * Retrieve this object's position (level) in its hierarchy. |
||
158 | * |
||
159 | * Starts at "1" (top-level). |
||
160 | * |
||
161 | * The level is calculated by loading all ancestors with {@see self::hierarchy()}. |
||
162 | * |
||
163 | * @return integer |
||
164 | */ |
||
165 | public function hierarchyLevel() |
||
172 | |||
173 | /** |
||
174 | * Retrieve the top-level ancestor of this object. |
||
175 | * |
||
176 | * @return HierarchicalInterface|null |
||
177 | */ |
||
178 | public function toplevelMaster() |
||
187 | |||
188 | /** |
||
189 | * Determine if this object has any ancestors. |
||
190 | * |
||
191 | * @return boolean |
||
192 | */ |
||
193 | public function hasParents() |
||
197 | |||
198 | /** |
||
199 | * Retrieve this object's ancestors (from immediate parent to top-level). |
||
200 | * |
||
201 | * @return array |
||
202 | */ |
||
203 | public function hierarchy() |
||
218 | |||
219 | /** |
||
220 | * Retrieve this object's ancestors, inverted from top-level to immediate. |
||
221 | * |
||
222 | * @return array |
||
223 | */ |
||
224 | public function invertedHierarchy() |
||
230 | |||
231 | /** |
||
232 | * Determine if the object is the parent of the given object. |
||
233 | * |
||
234 | * @param mixed $child The child (or ID) to match against. |
||
235 | * @return boolean |
||
236 | */ |
||
237 | public function isMasterOf($child) |
||
243 | |||
244 | /** |
||
245 | * Determine if the object is a parent/ancestor of the given object. |
||
246 | * |
||
247 | * @param mixed $child The child (or ID) to match against. |
||
248 | * @return boolean |
||
249 | * @todo Implementation needed. |
||
250 | */ |
||
251 | public function recursiveIsMasterOf($child) |
||
257 | |||
258 | /** |
||
259 | * Get wether the object has any children at all |
||
260 | * @return boolean |
||
261 | */ |
||
262 | public function hasChildren() |
||
268 | |||
269 | /** |
||
270 | * Get the number of children directly under this object. |
||
271 | * @return integer |
||
272 | */ |
||
273 | public function numChildren() |
||
279 | |||
280 | /** |
||
281 | * Get the total number of children in the entire hierarchy. |
||
282 | * This method counts all children and sub-children, unlike `numChildren()` which only count 1 level. |
||
283 | * @return integer |
||
284 | */ |
||
285 | public function recursiveNumChildren() |
||
290 | |||
291 | /** |
||
292 | * @param array $children The children to set. |
||
293 | * @return HierarchicalInterface Chainable |
||
294 | */ |
||
295 | public function setChildren(array $children) |
||
304 | |||
305 | /** |
||
306 | * @param mixed $child The child object (or ident) to add. |
||
307 | * @return HierarchicalInterface Chainable |
||
308 | * @throws UnexpectedValueException The current object cannot be its own child. |
||
309 | */ |
||
310 | public function addChild($child) |
||
327 | |||
328 | /** |
||
329 | * Get the children directly under this object. |
||
330 | * @return array |
||
331 | */ |
||
332 | public function children() |
||
342 | |||
343 | /** |
||
344 | * @return array |
||
345 | */ |
||
346 | abstract public function loadChildren(); |
||
347 | |||
348 | /** |
||
349 | * @param mixed $master The master object (or ident) to check against. |
||
350 | * @return boolean |
||
351 | */ |
||
352 | public function isChildOf($master) |
||
361 | |||
362 | /** |
||
363 | * @param mixed $master The master object (or ident) to check against. |
||
364 | * @return boolean |
||
365 | */ |
||
366 | public function recursiveIsChildOf($master) |
||
378 | |||
379 | /** |
||
380 | * @return boolean |
||
381 | */ |
||
382 | public function hasSiblings() |
||
388 | |||
389 | /** |
||
390 | * @return integer |
||
391 | */ |
||
392 | public function numSiblings() |
||
398 | |||
399 | /** |
||
400 | * Get all the objects on the same level as this one. |
||
401 | * @return array |
||
402 | */ |
||
403 | public function siblings() |
||
420 | |||
421 | /** |
||
422 | * @param mixed $sibling The sibling to check. |
||
423 | * @return boolean |
||
424 | */ |
||
425 | public function isSiblingOf($sibling) |
||
431 | |||
432 | /** |
||
433 | * @param mixed $ident The ident. |
||
434 | * @return HierarchicalInterface|null |
||
435 | * @throws InvalidArgumentException If the identifier is not a scalar value. |
||
436 | */ |
||
437 | private function objFromIdent($ident) |
||
473 | |||
474 | /** |
||
475 | * Retrieve an object from the storage source by its ID. |
||
476 | * |
||
477 | * @param mixed $id The object id. |
||
478 | * @return null|HierarchicalInterface |
||
479 | */ |
||
480 | private function loadObjectFromSource($id) |
||
491 | |||
492 | /** |
||
493 | * Retrieve an object from the cache store by its ID. |
||
494 | * |
||
495 | * @param mixed $id The object id. |
||
496 | * @return null|HierarchicalInterface |
||
497 | */ |
||
498 | private function loadObjectFromCache($id) |
||
507 | |||
508 | /** |
||
509 | * Add an object to the cache store. |
||
510 | * |
||
511 | * @param ModelInterface $obj The object to store. |
||
512 | * @return HierarchicalInterface Chainable |
||
513 | */ |
||
514 | private function addObjectToCache(ModelInterface $obj) |
||
520 | |||
521 | /** |
||
522 | * Retrieve the object model factory. |
||
523 | * |
||
524 | * @return \Charcoal\Factory\FactoryInterface |
||
525 | */ |
||
526 | abstract public function modelFactory(); |
||
527 | |||
528 | /** |
||
529 | * @return string |
||
530 | */ |
||
531 | abstract public function id(); |
||
532 | |||
533 | /** |
||
534 | * @return string |
||
535 | */ |
||
536 | abstract public function objType(); |
||
537 | } |
||
538 |
This check looks for variable assignements that are either overwritten by other assignments or where the variable is not used subsequently.
Both the
$myVar
assignment in line 1 and the$higher
assignment in line 2 are dead. The first because$myVar
is never used and the second because$higher
is always overwritten for every possible time line.