Complex classes like RevisionPrinter 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 RevisionPrinter, and based on these observations, apply Extract Interface, too.
1 | <?php |
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21 | class RevisionPrinter |
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22 | { |
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23 | |||
24 | const COLUMN_DETAILS = 1; |
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25 | |||
26 | const COLUMN_SUMMARY = 2; |
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27 | |||
28 | const COLUMN_REFS = 3; |
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29 | |||
30 | const COLUMN_MERGE_ORACLE = 4; |
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31 | |||
32 | const COLUMN_MERGE_STATUS = 5; |
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33 | |||
34 | /** |
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35 | * Date helper. |
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36 | * |
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37 | * @var DateHelper |
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38 | */ |
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39 | private $_dateHelper; |
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40 | |||
41 | /** |
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42 | * Output helper. |
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43 | * |
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44 | * @var OutputHelper |
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45 | */ |
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46 | private $_outputHelper; |
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47 | |||
48 | /** |
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49 | * Columns. |
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50 | * |
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51 | * @var array |
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52 | */ |
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53 | private $_columns = array(); |
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54 | |||
55 | /** |
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56 | * Merge conflict regexps. |
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57 | * |
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58 | * @var array |
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59 | */ |
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60 | private $_mergeConflictRegExps = array(); |
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61 | |||
62 | /** |
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63 | * Log message limit. |
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64 | * |
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65 | * @var integer |
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66 | */ |
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67 | private $_logMessageLimit = 68; |
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68 | |||
69 | /** |
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70 | * Current revision (e.g. in a working copy). |
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71 | * |
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72 | * @var integer|null |
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73 | */ |
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74 | private $_currentRevision; |
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75 | |||
76 | /** |
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77 | * Creates instance of revision printer. |
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78 | * |
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79 | * @param DateHelper $date_helper Date helper. |
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80 | * @param OutputHelper $output_helper Output helper. |
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81 | */ |
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82 | 1 | public function __construct(DateHelper $date_helper, OutputHelper $output_helper) |
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89 | |||
90 | /** |
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91 | * Resets state. |
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92 | * |
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93 | * @return void |
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94 | */ |
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95 | 1 | private function _resetState() |
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101 | |||
102 | /** |
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103 | * Adds column to the output. |
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104 | * |
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105 | * @param integer $column Column. |
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106 | * |
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107 | * @return self |
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108 | */ |
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109 | public function withColumn($column) |
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115 | |||
116 | /** |
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117 | * Sets merge conflict regexps. |
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118 | * |
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119 | * @param array $merge_conflict_regexps Merge conflict regexps. |
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120 | * |
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121 | * @return void |
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122 | */ |
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123 | public function setMergeConflictRegExps(array $merge_conflict_regexps) |
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127 | |||
128 | /** |
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129 | * Sets log message limit. |
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130 | * |
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131 | * @param integer $log_message_limit Log message limit. |
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132 | * |
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133 | * @return void |
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134 | */ |
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135 | public function setLogMessageLimit($log_message_limit) |
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139 | |||
140 | /** |
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141 | * Sets current revision. |
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142 | * |
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143 | * @param integer $revision Revision. |
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144 | * |
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145 | * @return void |
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146 | */ |
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147 | public function setCurrentRevision($revision) |
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151 | |||
152 | /** |
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153 | * Prints revisions. |
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154 | * |
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155 | * @param RevisionLog $revision_log Revision log. |
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156 | * @param array $revisions Revisions. |
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157 | * @param OutputInterface $output Output. |
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158 | * |
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159 | * @return void |
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160 | */ |
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161 | public function printRevisions(RevisionLog $revision_log, array $revisions, OutputInterface $output) |
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299 | |||
300 | /** |
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301 | * Returns log message. |
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302 | * |
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303 | * @param boolean $with_details With details. |
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304 | * @param array $revision_data Revision data. |
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305 | * |
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306 | * @return string |
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307 | */ |
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308 | private function _generateLogMessageColumn($with_details, array $revision_data) |
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333 | |||
334 | /** |
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335 | * Generates change summary for a revision. |
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336 | * |
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337 | * @param array $revision_paths Revision paths. |
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338 | * |
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339 | * @return string |
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340 | */ |
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341 | private function _generateSummaryColumn(array $revision_paths) |
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369 | |||
370 | /** |
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371 | * Returns merge conflict path predictions. |
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372 | * |
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373 | * @param array $revision_paths Revision paths. |
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374 | * |
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375 | * @return array |
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376 | */ |
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377 | private function _getMergeConflictPrediction(array $revision_paths) |
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395 | |||
396 | /** |
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397 | * Generates content for "Merged Via" cell content. |
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398 | * |
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399 | * @param array $merged_via Merged Via. |
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400 | * @param array $revisions_merged_via_refs Merged Via Refs. |
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401 | * |
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402 | * @return string |
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403 | */ |
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404 | private function _generateMergedViaColumn(array $merged_via, array $revisions_merged_via_refs) |
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425 | |||
426 | /** |
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427 | * Generates details row content. |
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428 | * |
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429 | * @param integer $revision Revision. |
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430 | * @param array $revisions_refs Refs. |
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431 | * @param array $revision_paths Revision paths. |
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432 | * @param array $merge_conflict_prediction Merge conflict prediction. |
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433 | * @param string $project_path Project path. |
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434 | * |
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435 | * @return string |
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436 | */ |
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437 | private function _generateDetailsRowContent( |
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484 | |||
485 | /** |
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486 | * Returns path cut off regexp. |
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487 | * |
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488 | * @param string $project_path Project path. |
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489 | * @param array $refs Refs. |
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490 | * |
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491 | * @return string |
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492 | */ |
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493 | protected function getPathCutOffRegExp($project_path, array $refs) |
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507 | |||
508 | /** |
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509 | * Returns relative path to "svn log" returned path. |
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510 | * |
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511 | * @param array $path_data Path data. |
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512 | * @param string $path_key Path key. |
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513 | * @param string $path_cut_off_regexp Path cut off regexp. |
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514 | * |
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515 | * @return string |
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516 | */ |
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517 | private function _getRelativeLogPath(array $path_data, $path_key, $path_cut_off_regexp) |
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527 | |||
528 | } |
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529 |
If you define a variable conditionally, it can happen that it is not defined for all execution paths.
Let’s take a look at an example:
In the above example, the variable $x is defined if you pass “foo” or “bar” as argument for $a. However, since the switch statement has no default case statement, if you pass any other value, the variable $x would be undefined.
Available Fixes
Check for existence of the variable explicitly:
Define a default value for the variable:
Add a value for the missing path: