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 LazyKeyedIterableTrait 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 LazyKeyedIterableTrait, and based on these observations, apply Extract Interface, too.
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14 | trait LazyKeyedIterableTrait |
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15 | { |
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16 | public function toArray() |
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25 | |||
26 | public function toValuesArray() |
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35 | |||
36 | public function toKeysArray() |
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45 | |||
46 | public function toVector() |
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50 | |||
51 | public function toImmVector() |
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55 | |||
56 | public function toMap() |
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60 | |||
61 | public function toImmMap() |
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65 | |||
66 | public function toSet() |
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70 | |||
71 | public function toImmSet() |
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75 | |||
76 | public function lazy() |
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80 | |||
81 | public function values() |
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85 | |||
86 | public function keys() |
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90 | |||
91 | public function map($callback) |
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95 | |||
96 | public function mapWithKey($callback) |
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100 | |||
101 | public function filter($callback) |
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105 | |||
106 | public function filterWithKey($callback) |
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110 | |||
111 | public function zip($traversable) |
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119 | |||
120 | public function take($n) |
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124 | |||
125 | public function takeWhile($fn) |
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129 | |||
130 | public function skip($n) |
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134 | |||
135 | public function skipWhile($fn) |
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139 | |||
140 | public function slice($start, $len) |
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144 | |||
145 | public function concat($iterable) |
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153 | |||
154 | public function first() |
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162 | |||
163 | public function firstKey() |
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171 | |||
172 | public function last() |
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180 | |||
181 | public function lastKey() |
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189 | |||
190 | /** |
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191 | * {@inheritDoc} |
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192 | * @return $this |
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193 | */ |
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194 | public function each(callable $callable) |
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202 | |||
203 | /** |
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204 | * {@inheritdoc} |
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205 | */ |
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206 | public function exists(callable $fn) |
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216 | |||
217 | View Code Duplication | public function concatAll() |
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229 | |||
230 | /** |
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231 | * {@inheritDoc} |
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232 | * @return $this |
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233 | */ |
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234 | View Code Duplication | public function groupBy($callback) |
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250 | |||
251 | /** |
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252 | * {@inheritDoc} |
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253 | * @return $this |
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254 | */ |
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255 | View Code Duplication | public function indexBy($callback) |
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265 | |||
266 | /** |
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267 | * {@inheritdoc} |
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268 | */ |
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269 | public function reduce(callable $callback, $initial = null) |
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277 | } |