Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like BaseNode 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 BaseNode, and based on these observations, apply Extract Interface, too.
1 | <?php |
||
15 | class BaseNode |
||
16 | { |
||
17 | /** |
||
18 | * @var ConstraintInterface[] |
||
19 | */ |
||
20 | protected $constraints = []; |
||
21 | |||
22 | /** |
||
23 | * @var TransformerInterface |
||
24 | */ |
||
25 | protected $transformer; |
||
26 | |||
27 | /** |
||
28 | * @var InstantiatorInterface |
||
29 | */ |
||
30 | protected $instantiator; |
||
31 | |||
32 | /** |
||
33 | * @var string |
||
34 | */ |
||
35 | protected $type = 'array'; |
||
36 | |||
37 | /** |
||
38 | * @var string |
||
39 | */ |
||
40 | protected $typeAlias = 'array'; |
||
41 | |||
42 | /** |
||
43 | * @var bool |
||
44 | */ |
||
45 | protected $required = true; |
||
46 | |||
47 | /** |
||
48 | * @var mixed |
||
49 | */ |
||
50 | protected $default; |
||
51 | |||
52 | /** |
||
53 | * @var BaseNode[] |
||
54 | */ |
||
55 | protected $children = []; |
||
56 | |||
57 | /** |
||
58 | * @var TypeHandler |
||
59 | */ |
||
60 | protected $typeHandler; |
||
61 | |||
62 | /** |
||
63 | * @var bool |
||
64 | */ |
||
65 | protected $allowNull = false; |
||
66 | |||
67 | public function setConstraints(array $constraints) |
||
71 | |||
72 | public function addConstraint(ConstraintInterface $constraint) |
||
76 | |||
77 | public function addConstraints(array $constraints) |
||
81 | |||
82 | public function setTransformer(TransformerInterface $transformer) |
||
86 | |||
87 | public function setInstantiator(InstantiatorInterface $instantiator) |
||
91 | |||
92 | public function setTypeHandler(TypeHandler $typeHandler) |
||
96 | |||
97 | public function setType(string $type) |
||
101 | |||
102 | public function setTypeAlias(string $typeAlias) |
||
106 | |||
107 | public function getTypeAlias(): string |
||
111 | |||
112 | public function setRequired(bool $required) |
||
116 | |||
117 | public function setDefault($default) |
||
121 | |||
122 | public function setAllowNull(bool $allowNull) |
||
126 | |||
127 | public function getDefault() |
||
131 | |||
132 | public function hasDefault(): bool |
||
136 | |||
137 | public function add(string $key, string $type, array $options = []): BaseNode |
||
178 | |||
179 | public function remove(string $key) |
||
183 | |||
184 | /** |
||
185 | * @return BaseNode[] |
||
186 | */ |
||
187 | public function getChildren(): array |
||
191 | |||
192 | public function hasChildren(): bool |
||
196 | |||
197 | public function isRequired(): bool |
||
205 | |||
206 | public function allowNull(): bool |
||
210 | |||
211 | public function getValue(string $field, $value) |
||
225 | |||
226 | public function walk($input) |
||
252 | |||
253 | protected function checkConstraints(string $field, $value) |
||
261 | } |
||
262 |
Our type inference engine has found an assignment to a property that is incompatible with the declared type of that property.
Either this assignment is in error or the assigned type should be added to the documentation/type hint for that property..