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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| 29 | class ChangeSetItem extends DataObject implements Thumbnail { |
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| 30 | |||
| 31 | const EXPLICITLY = 'explicitly'; |
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| 32 | |||
| 33 | const IMPLICITLY = 'implicitly'; |
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| 34 | |||
| 35 | /** Represents an object deleted */ |
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| 36 | const CHANGE_DELETED = 'deleted'; |
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| 37 | |||
| 38 | /** Represents an object which was modified */ |
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| 39 | const CHANGE_MODIFIED = 'modified'; |
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| 40 | |||
| 41 | /** Represents an object added */ |
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| 42 | const CHANGE_CREATED = 'created'; |
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| 43 | |||
| 44 | /** Represents an object which hasn't been changed directly, but owns a modified many_many relationship. */ |
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| 45 | //const CHANGE_MANYMANY = 'manymany'; |
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| 46 | |||
| 47 | private static $table_name = 'ChangeSetItem'; |
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| 48 | |||
| 49 | /** |
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| 50 | * Represents that an object has not yet been changed, but |
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| 51 | * should be included in this changeset as soon as any changes exist |
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| 52 | */ |
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| 53 | const CHANGE_NONE = 'none'; |
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| 54 | |||
| 55 | private static $db = array( |
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| 56 | 'VersionBefore' => 'Int', |
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| 57 | 'VersionAfter' => 'Int', |
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| 58 | 'Added' => "Enum('explicitly, implicitly', 'implicitly')" |
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| 59 | ); |
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| 60 | |||
| 61 | private static $has_one = array( |
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| 62 | 'ChangeSet' => 'SilverStripe\ORM\Versioning\ChangeSet', |
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| 63 | 'Object' => 'SilverStripe\ORM\DataObject', |
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| 64 | ); |
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| 65 | |||
| 66 | private static $many_many = array( |
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| 67 | 'ReferencedBy' => 'SilverStripe\ORM\Versioning\ChangeSetItem' |
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| 68 | ); |
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| 69 | |||
| 70 | private static $belongs_many_many = array( |
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| 71 | 'References' => 'ChangeSetItem.ReferencedBy' |
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| 72 | ); |
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| 73 | |||
| 74 | private static $indexes = array( |
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| 75 | 'ObjectUniquePerChangeSet' => array( |
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| 76 | 'type' => 'unique', |
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| 77 | 'value' => '"ObjectID", "ObjectClass", "ChangeSetID"' |
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| 78 | ) |
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| 79 | ); |
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| 80 | |||
| 81 | public function onBeforeWrite() { |
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| 86 | |||
| 87 | public function getTitle() { |
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| 95 | |||
| 96 | /** |
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| 97 | * Get a thumbnail for this object |
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| 98 | * |
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| 99 | * @param int $width Preferred width of the thumbnail |
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| 100 | * @param int $height Preferred height of the thumbnail |
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| 101 | * @return string URL to the thumbnail, if available |
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| 102 | */ |
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| 103 | public function ThumbnailURL($width, $height) { |
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| 110 | |||
| 111 | /** |
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| 112 | * Get the type of change: none, created, deleted, modified, manymany |
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| 113 | * @return string |
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| 114 | * @throws UnexpectedDataException |
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| 115 | */ |
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| 116 | public function getChangeType() { |
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| 145 | |||
| 146 | /** |
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| 147 | * Find version of this object in the given stage |
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| 148 | * |
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| 149 | * @param string $stage |
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| 150 | * @return DataObject|Versioned |
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| 151 | * @throws UnexpectedDataException |
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| 152 | */ |
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| 153 | View Code Duplication | protected function getObjectInStage($stage) { |
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| 160 | |||
| 161 | /** |
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| 162 | * Find latest version of this object |
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| 163 | * @return DataObject|Versioned |
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| 164 | * @throws UnexpectedDataException |
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| 165 | */ |
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| 166 | View Code Duplication | protected function getObjectLatestVersion() { |
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| 173 | |||
| 174 | /** |
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| 175 | * Get all implicit objects for this change |
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| 176 | * |
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| 177 | * @return SS_List |
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| 178 | */ |
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| 179 | public function findReferenced() { |
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| 199 | |||
| 200 | /** |
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| 201 | * Publish this item, then close it. |
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| 202 | * |
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| 203 | * Note: Unlike Versioned::doPublish() and Versioned::doUnpublish, this action is not recursive. |
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| 204 | */ |
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| 205 | public function publish() { |
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| 247 | |||
| 248 | /** |
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| 249 | * Once this item (and all owned objects) are published, unlink |
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| 250 | * all disowned objects |
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| 251 | */ |
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| 252 | public function unlinkDisownedObjects() { |
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| 258 | |||
| 259 | /** Reverts this item, then close it. **/ |
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| 260 | public function revert() { |
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| 263 | |||
| 264 | public function canView($member = null) { |
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| 267 | |||
| 268 | public function canEdit($member = null) { |
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| 271 | |||
| 272 | public function canCreate($member = null, $context = array()) { |
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| 275 | |||
| 276 | public function canDelete($member = null) { |
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| 279 | |||
| 280 | /** |
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| 281 | * Check if the BeforeVersion of this changeset can be restored to draft |
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| 282 | * |
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| 283 | * @param Member $member |
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| 284 | * @return bool |
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| 285 | */ |
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| 286 | public function canRevert($member) { |
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| 306 | |||
| 307 | /** |
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| 308 | * Check if this ChangeSetItem can be published |
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| 309 | * |
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| 310 | * @param Member $member |
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| 311 | * @return bool |
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| 312 | */ |
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| 313 | public function canPublish($member = null) { |
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| 336 | |||
| 337 | /** |
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| 338 | * Default permissions for this ChangeSetItem |
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| 339 | * |
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| 340 | * @param string $perm |
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| 341 | * @param Member $member |
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| 342 | * @param array $context |
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| 343 | * @return bool |
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| 344 | */ |
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| 345 | View Code Duplication | public function can($perm, $member = null, $context = array()) { |
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| 360 | |||
| 361 | /** |
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| 362 | * Get the ChangeSetItems that reference a passed DataObject |
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| 363 | * |
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| 364 | * @param DataObject $object |
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| 365 | * @return DataList |
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| 366 | */ |
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| 367 | public static function get_for_object($object) { |
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| 373 | |||
| 374 | /** |
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| 375 | * Get the ChangeSetItems that reference a passed DataObject |
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| 376 | * |
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| 377 | * @param int $objectID The ID of the object |
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| 378 | * @param string $objectClass The class of the object (or any parent class) |
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| 379 | * @return DataList |
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| 380 | */ |
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| 381 | public static function get_for_object_by_id($objectID, $objectClass) { |
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| 387 | |||
| 388 | /** |
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| 389 | * Gets the list of modes this record can be previewed in. |
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| 390 | * |
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| 391 | * {@link https://tools.ietf.org/html/draft-kelly-json-hal-07#section-5} |
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| 392 | * |
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| 393 | * @return array Map of links in acceptable HAL format |
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| 394 | */ |
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| 395 | public function getPreviewLinks() { |
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| 418 | |||
| 419 | /** |
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| 420 | * Get edit link for this item |
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| 421 | * |
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| 422 | * @return string |
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| 423 | */ |
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| 424 | public function CMSEditLink() |
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| 432 | } |
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| 433 |