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 ChangeSetItem 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 ChangeSetItem, and based on these observations, apply Extract Interface, too.
1 | <?php |
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28 | class ChangeSetItem extends DataObject implements Thumbnail { |
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29 | |||
30 | const EXPLICITLY = 'explicitly'; |
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31 | |||
32 | const IMPLICITLY = 'implicitly'; |
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33 | |||
34 | /** Represents an object deleted */ |
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35 | const CHANGE_DELETED = 'deleted'; |
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36 | |||
37 | /** Represents an object which was modified */ |
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38 | const CHANGE_MODIFIED = 'modified'; |
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39 | |||
40 | /** Represents an object added */ |
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41 | const CHANGE_CREATED = 'created'; |
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42 | |||
43 | /** Represents an object which hasn't been changed directly, but owns a modified many_many relationship. */ |
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44 | //const CHANGE_MANYMANY = 'manymany'; |
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45 | |||
46 | private static $table_name = 'ChangeSetItem'; |
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47 | |||
48 | /** |
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49 | * Represents that an object has not yet been changed, but |
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50 | * should be included in this changeset as soon as any changes exist |
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51 | */ |
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52 | const CHANGE_NONE = 'none'; |
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53 | |||
54 | private static $db = array( |
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55 | 'VersionBefore' => 'Int', |
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56 | 'VersionAfter' => 'Int', |
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57 | 'Added' => "Enum('explicitly, implicitly', 'implicitly')" |
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58 | ); |
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59 | |||
60 | private static $has_one = array( |
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61 | 'ChangeSet' => 'SilverStripe\ORM\Versioning\ChangeSet', |
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62 | 'Object' => 'SilverStripe\ORM\DataObject', |
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63 | ); |
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64 | |||
65 | private static $many_many = array( |
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66 | 'ReferencedBy' => 'SilverStripe\ORM\Versioning\ChangeSetItem' |
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67 | ); |
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68 | |||
69 | private static $belongs_many_many = array( |
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70 | 'References' => 'ChangeSetItem.ReferencedBy' |
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71 | ); |
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72 | |||
73 | private static $indexes = array( |
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74 | 'ObjectUniquePerChangeSet' => array( |
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75 | 'type' => 'unique', |
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76 | 'value' => '"ObjectID", "ObjectClass", "ChangeSetID"' |
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77 | ) |
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78 | ); |
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79 | |||
80 | public function onBeforeWrite() { |
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85 | |||
86 | public function getTitle() { |
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94 | |||
95 | /** |
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96 | * Get a thumbnail for this object |
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97 | * |
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98 | * @param int $width Preferred width of the thumbnail |
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99 | * @param int $height Preferred height of the thumbnail |
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100 | * @return string URL to the thumbnail, if available |
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101 | */ |
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102 | public function ThumbnailURL($width, $height) { |
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109 | |||
110 | /** |
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111 | * Get the type of change: none, created, deleted, modified, manymany |
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112 | * |
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113 | * @return string |
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114 | */ |
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115 | public function getChangeType() { |
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144 | |||
145 | /** |
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146 | * Find version of this object in the given stage |
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147 | * |
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148 | * @param string $stage |
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149 | * @return Versioned|DataObject |
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150 | */ |
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151 | View Code Duplication | protected function getObjectInStage($stage) { |
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158 | |||
159 | /** |
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160 | * Find latest version of this object |
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161 | * |
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162 | * @return Versioned|DataObject |
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163 | */ |
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164 | View Code Duplication | protected function getObjectLatestVersion() { |
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171 | |||
172 | /** |
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173 | * Get all implicit objects for this change |
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174 | * |
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175 | * @return SS_List |
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176 | */ |
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177 | public function findReferenced() { |
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189 | |||
190 | /** |
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191 | * Publish this item, then close it. |
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192 | * |
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193 | * Note: Unlike Versioned::doPublish() and Versioned::doUnpublish, this action is not recursive. |
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194 | */ |
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195 | public function publish() { |
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237 | |||
238 | /** Reverts this item, then close it. **/ |
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239 | public function revert() { |
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242 | |||
243 | public function canView($member = null) { |
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246 | |||
247 | public function canEdit($member = null) { |
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250 | |||
251 | public function canCreate($member = null, $context = array()) { |
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254 | |||
255 | public function canDelete($member = null) { |
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258 | |||
259 | /** |
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260 | * Check if the BeforeVersion of this changeset can be restored to draft |
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261 | * |
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262 | * @param Member $member |
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263 | * @return bool |
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264 | */ |
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265 | public function canRevert($member) { |
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294 | |||
295 | /** |
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296 | * Check if this ChangeSetItem can be published |
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297 | * |
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298 | * @param Member $member |
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299 | * @return bool |
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300 | */ |
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301 | public function canPublish($member = null) { |
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325 | |||
326 | /** |
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327 | * Default permissions for this ChangeSetItem |
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328 | * |
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329 | * @param string $perm |
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330 | * @param Member $member |
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331 | * @param array $context |
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332 | * @return bool |
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333 | */ |
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334 | View Code Duplication | public function can($perm, $member = null, $context = array()) { |
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349 | |||
350 | /** |
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351 | * Get the ChangeSetItems that reference a passed DataObject |
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352 | * |
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353 | * @param DataObject $object |
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354 | * @return DataList |
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355 | */ |
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356 | public static function get_for_object($object) { |
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362 | |||
363 | /** |
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364 | * Get the ChangeSetItems that reference a passed DataObject |
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365 | * |
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366 | * @param int $objectID The ID of the object |
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367 | * @param string $objectClass The class of the object (or any parent class) |
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368 | * @return DataList |
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369 | */ |
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370 | public static function get_for_object_by_id($objectID, $objectClass) { |
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376 | |||
377 | /** |
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378 | * Gets the list of modes this record can be previewed in. |
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379 | * |
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380 | * {@link https://tools.ietf.org/html/draft-kelly-json-hal-07#section-5} |
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381 | * |
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382 | * @return array Map of links in acceptable HAL format |
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383 | */ |
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384 | public function getPreviewLinks() { |
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407 | |||
408 | /** |
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409 | * Get edit link for this item |
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410 | * |
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411 | * @return string |
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412 | */ |
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413 | public function CMSEditLink() |
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421 | } |
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422 |