Complex classes like Cursor 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 Cursor, and based on these observations, apply Extract Interface, too.
1 | <?php |
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14 | class Cursor |
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15 | { |
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16 | const INDENT_LEVEL = 4; |
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17 | |||
18 | /** |
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19 | * @var string |
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20 | */ |
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21 | private $line; |
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22 | |||
23 | /** |
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24 | * @var int |
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25 | */ |
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26 | private $length; |
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27 | |||
28 | /** |
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29 | * @var int |
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30 | * |
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31 | * It's possible for this to be 1 char past the end, meaning we've parsed all chars and have |
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32 | * reached the end. In this state, any character-returning method MUST return null. |
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33 | */ |
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34 | private $currentPosition = 0; |
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35 | |||
36 | /** |
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37 | * @var int |
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38 | */ |
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39 | private $column = 0; |
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40 | |||
41 | /** |
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42 | * @var int |
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43 | */ |
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44 | private $indent = 0; |
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45 | |||
46 | /** |
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47 | * @var int |
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48 | */ |
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49 | private $previousPosition = 0; |
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50 | |||
51 | /** |
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52 | * @var int|null |
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53 | */ |
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54 | private $nextNonSpaceCache; |
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55 | |||
56 | /** |
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57 | * @var bool |
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58 | */ |
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59 | private $partiallyConsumedTab = false; |
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60 | |||
61 | /** |
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62 | * @var string |
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63 | */ |
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64 | private $encoding; |
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65 | |||
66 | /** |
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67 | * @var bool |
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68 | */ |
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69 | private $lineContainsTabs; |
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70 | |||
71 | /** |
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72 | * @var bool |
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73 | */ |
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74 | private $isMultibyte; |
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75 | |||
76 | /** |
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77 | * @param string $line |
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78 | */ |
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79 | 2391 | public function __construct($line) |
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87 | |||
88 | /** |
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89 | * Returns the position of the next character which is not a space (or tab) |
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90 | * |
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91 | * @return int |
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92 | */ |
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93 | 2118 | public function getNextNonSpacePosition() |
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119 | |||
120 | /** |
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121 | * Returns the next character which isn't a space (or tab) |
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122 | * |
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123 | * @return string |
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124 | */ |
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125 | 1911 | public function getNextNonSpaceCharacter() |
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129 | |||
130 | /** |
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131 | * Calculates the current indent (number of spaces after current position) |
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132 | * |
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133 | * @return int |
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134 | */ |
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135 | 1890 | public function getIndent() |
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141 | |||
142 | /** |
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143 | * Whether the cursor is indented to INDENT_LEVEL |
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144 | * |
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145 | * @return bool |
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146 | */ |
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147 | 1938 | public function isIndented() |
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153 | |||
154 | /** |
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155 | * @param int|null $index |
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156 | * |
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157 | * @return string|null |
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158 | */ |
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159 | 2172 | public function getCharacter($index = null) |
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172 | |||
173 | /** |
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174 | * Returns the next character (or null, if none) without advancing forwards |
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175 | * |
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176 | * @param int $offset |
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177 | * |
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178 | * @return string|null |
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179 | */ |
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180 | 1014 | public function peek($offset = 1) |
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184 | |||
185 | /** |
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186 | * Whether the remainder is blank |
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187 | * |
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188 | * @return bool |
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189 | */ |
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190 | 1956 | public function isBlank() |
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194 | |||
195 | /** |
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196 | * Move the cursor forwards |
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197 | */ |
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198 | 795 | public function advance() |
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202 | |||
203 | /** |
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204 | * Move the cursor forwards |
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205 | * |
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206 | * @param int $characters Number of characters to advance by |
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207 | * @param bool $advanceByColumns Whether to advance by columns instead of spaces |
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208 | */ |
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209 | 2247 | public function advanceBy($characters, $advanceByColumns = false) |
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265 | |||
266 | /** |
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267 | * Advances the cursor by a single space or tab, if present |
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268 | * |
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269 | * @return bool |
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270 | */ |
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271 | 339 | public function advanceBySpaceOrTab() |
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283 | |||
284 | /** |
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285 | * Parse zero or more space/tab characters |
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286 | * |
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287 | * @return int Number of positions moved |
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288 | */ |
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289 | 1848 | public function advanceToNextNonSpaceOrTab() |
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297 | |||
298 | /** |
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299 | * Parse zero or more space characters, including at most one newline. |
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300 | * |
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301 | * Tab characters are not parsed with this function. |
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302 | * |
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303 | * @return int Number of positions moved |
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304 | */ |
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305 | 441 | public function advanceToNextNonSpaceOrNewline() |
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322 | |||
323 | /** |
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324 | * Move the position to the very end of the line |
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325 | * |
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326 | * @return int The number of characters moved |
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327 | */ |
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328 | 84 | public function advanceToEnd() |
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337 | |||
338 | /** |
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339 | * @return string |
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340 | */ |
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341 | 2043 | public function getRemainder() |
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357 | |||
358 | /** |
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359 | * @return string |
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360 | */ |
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361 | 1887 | public function getLine() |
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365 | |||
366 | /** |
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367 | * @return bool |
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368 | */ |
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369 | 411 | public function isAtEnd() |
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373 | |||
374 | /** |
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375 | * Try to match a regular expression |
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376 | * |
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377 | * Returns the matching text and advances to the end of that match |
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378 | * |
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379 | * @param string $regex |
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380 | * |
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381 | * @return string|null |
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382 | */ |
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383 | 1908 | public function match($regex) |
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407 | |||
408 | /** |
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409 | * Encapsulates the current state of this cursor in case you need to rollback later. |
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410 | * |
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411 | * WARNING: Do not parse or use the return value for ANYTHING except for |
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412 | * passing it back into restoreState(), as the number of values and their |
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413 | * contents may change in any future release without warning. |
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414 | * |
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415 | * @return array |
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416 | */ |
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417 | 1011 | public function saveState() |
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428 | |||
429 | /** |
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430 | * Restore the cursor to a previous state. |
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431 | * |
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432 | * Pass in the value previously obtained by calling saveState(). |
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433 | * |
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434 | * @param array $state |
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435 | */ |
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436 | 795 | public function restoreState($state) |
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447 | |||
448 | /** |
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449 | * @return int |
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450 | */ |
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451 | 648 | public function getPosition() |
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455 | |||
456 | /** |
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457 | * @return string |
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458 | */ |
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459 | 870 | public function getPreviousText() |
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463 | |||
464 | /** |
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465 | * @return int |
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466 | */ |
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467 | 240 | public function getColumn() |
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471 | } |
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472 |