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 StringConditionTree 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 StringConditionTree, and based on these observations, apply Extract Interface, too.
1 | <?php declare(strict_types = 1); |
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14 | class StringConditionTree |
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15 | { |
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16 | /** Tree node root element identifier, needed for recursion */ |
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17 | const ROOT_NAME = ''; |
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18 | |||
19 | /** Final tree node branch identifier */ |
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20 | const SELF_NAME = '@self'; |
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21 | |||
22 | /** String parameter start marker */ |
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23 | const PARAMETER_START = '{'; |
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24 | |||
25 | /** String parameter end marker */ |
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26 | const PARAMETER_END = '}'; |
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27 | |||
28 | /** Parameter sorting length value for counting */ |
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29 | const PARAMETER_COF = 2000; |
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30 | |||
31 | /** @var TreeNode Resulting collection for debugging */ |
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32 | protected $debug; |
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33 | |||
34 | /** @var array Collection of input string => identifier */ |
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35 | protected $source; |
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36 | |||
37 | /** @var string Parametrized string start marker */ |
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38 | protected $parameterStartMarker = self::PARAMETER_START; |
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39 | |||
40 | /** @var string Parametrized string end marker */ |
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41 | protected $parameterEndMarker = self::PARAMETER_END; |
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42 | |||
43 | /** |
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44 | * StringConditionTree constructor. |
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45 | * |
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46 | * @param string $parameterStartMarker Parametrized string start marker |
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47 | * @param string $parameterEndMarker Parametrized string end marker |
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48 | */ |
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49 | public function __construct(string $parameterStartMarker = self::PARAMETER_START, string $parameterEndMarker = self::PARAMETER_END) |
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54 | |||
55 | /** |
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56 | * Build similarity strings tree. |
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57 | * |
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58 | * @param array $input Collection of strings |
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59 | * |
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60 | * @return TreeNode Resulting similarity strings tree |
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61 | */ |
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62 | public function process(array $input): TreeNode |
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76 | |||
77 | /** |
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78 | * Build string character group structure considering parametrized |
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79 | * and not parametrized character groups and their length(PCG, NPCG). |
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80 | * |
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81 | * @param string $prefix Prefix string |
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82 | * |
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83 | * @return array String character groups structure |
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84 | */ |
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85 | protected function getPrefixStructure(string $prefix): array |
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127 | |||
128 | /** |
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129 | * Compare string structures. |
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130 | * |
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131 | * @param array $initial Initial string structure |
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132 | * @param array $compared Compared string structure |
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133 | * |
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134 | * @return int Result of array elements comparison |
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135 | */ |
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136 | protected function compareStringStructure(array $initial, array $compared): int |
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211 | |||
212 | /** |
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213 | * Sort strings array considering PCG and NPCG string structure. |
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214 | * |
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215 | * @param array $input Input array for sorting |
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216 | * @return array Sorted array |
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217 | */ |
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218 | protected function sortArrayByKeys(array &$input) |
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231 | |||
232 | /** |
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233 | * Add only unique value to array. |
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234 | * |
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235 | * @param mixed $value Unique value |
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236 | * @param array $array Array for adding unique value |
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237 | * @param bool $strict Strict uniqueness check |
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238 | * |
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239 | * @return bool True if unique value was added |
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240 | * @see in_array(); |
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241 | * |
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242 | */ |
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243 | protected function addUniqueToArray($value, &$array, bool $strict = true) |
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259 | |||
260 | /** |
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261 | * Find longest matching prefix between two strings. |
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262 | * |
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263 | * @param string $initialString Initial string |
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264 | * @param string $comparedString Compared string |
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265 | * |
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266 | * @return string Longest matching prefix |
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267 | */ |
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268 | protected function getLongestMatchingPrefix(string $initialString, string $comparedString): string |
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322 | |||
323 | /** |
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324 | * Remove key string from the beginning of all sub-array strings. |
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325 | * |
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326 | * @param array $array Input array of key => [keyStrings...] |
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327 | * |
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328 | * @return array Processed array with removed keys from beginning of sub arrays |
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329 | */ |
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330 | protected function removeKeyFromArrayStrings(array $array): array |
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352 | |||
353 | /** |
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354 | * Find all duplication of source array values in compared array and remove them. |
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355 | * |
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356 | * @param array $source Source array |
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357 | * @param array $compared Compared array for filtering duplicates |
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358 | */ |
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359 | protected function removeDuplicatesInSubArray(array $source, array &$compared) |
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369 | |||
370 | /** |
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371 | * Iterate LMP and remove duplicate strings in other LMPs. |
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372 | * |
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373 | * @param array $prefixes LMP collection, returning value |
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374 | */ |
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375 | protected function filterLMPStrings(array &$prefixes) |
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384 | |||
385 | /** |
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386 | * Get collection of grouped longest matching prefixes with strings sub-array. |
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387 | * |
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388 | * @param array $input Input strings array |
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389 | * |
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390 | * @return array Longest matching prefixes array |
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391 | */ |
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392 | protected function getLMPCollection(array $input): array |
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417 | |||
418 | /** |
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419 | * Recursive string similarity tree builder. |
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420 | * |
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421 | * @param string $prefix |
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422 | * @param array $input |
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423 | * @param TreeNode $result |
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424 | * @param string $selfMarker |
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425 | */ |
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426 | protected function innerProcessor(string $prefix, array $input, TreeNode $result, $selfMarker = self::SELF_NAME) |
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460 | } |
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461 |
Our type inference engine has found a suspicous assignment of a value to a property. This check raises an issue when a value that can be of a given class or a super-class is assigned to a property that is type hinted more strictly.
Either this assignment is in error or an instanceof check should be added for that assignment.