Complex classes like NestedSet 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 NestedSet, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 23 | class NestedSet  | 
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| 24 | implements TreeInterface  | 
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| 25 | { | 
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| 26 | private $adapter;  | 
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| 27 | |||
| 28 | private $validator;  | 
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| 29 | |||
| 30 | /**  | 
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| 31 | * @param Options $options  | 
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| 32 | * @param object $dbAdapter  | 
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| 33 | * @return TreeInterface  | 
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| 34 | * @throws InvalidArgumentException  | 
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| 35 | */  | 
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| 36 | 4 | public static function factory(Options $options, $dbAdapter)  | 
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| 37 |     { | 
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| 38 | 4 |         if ($dbAdapter instanceof ExtendedAdapterInterface) { | 
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| 39 | 1 | $adapter = new Zend2DbAdapter($options, $dbAdapter);  | 
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| 40 |         } elseif ($dbAdapter instanceof DoctrineConnection) { | 
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| 41 | 1 | $adapter = new Doctrine2DBALAdapter($options, $dbAdapter);  | 
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| 42 |         } elseif ($dbAdapter instanceof Zend_Db_Adapter_Abstract) { | 
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| 43 | 1 | $adapter = new Zend1DbAdapter($options, $dbAdapter);  | 
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| 44 |         } else { | 
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| 45 | 1 |             throw new InvalidArgumentException('Db adapter "' . get_class($dbAdapter) | 
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| 46 | 1 | . '" is not supported');  | 
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| 47 | }  | 
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| 48 | |||
| 49 | 3 | return new self($adapter);  | 
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| 50 | }  | 
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| 51 | |||
| 52 | /**  | 
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| 53 | * @param AdapterInterface $adapter  | 
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| 54 | */  | 
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| 55 | 105 | public function __construct(AdapterInterface $adapter)  | 
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| 59 | |||
| 60 | /**  | 
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| 61 | * @return AdapterInterface  | 
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| 62 | */  | 
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| 63 | 105 | public function getAdapter()  | 
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| 67 | |||
| 68 | /**  | 
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| 69 | * @return ValidatorInterface  | 
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| 70 | */  | 
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| 71 | 9 | private function _getValidator()  | 
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| 72 |     { | 
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| 73 | 9 |         if (null == $this->validator) { | 
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| 74 | 9 | $this->validator = new Validator($this->getAdapter());  | 
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| 75 | }  | 
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| 76 | |||
| 77 | 9 | return $this->validator;  | 
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| 78 | }  | 
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| 79 | |||
| 80 | 15 | public function createRootNode($data = array(), $scope = null)  | 
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| 92 | |||
| 93 | /**  | 
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| 94 | * @param int $nodeId  | 
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| 95 | * @param array $data  | 
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| 96 | */  | 
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| 97 | 6 | public function updateNode($nodeId, $data)  | 
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| 102 | |||
| 103 | /**  | 
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| 104 | * @param int $targetNodeId  | 
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| 105 | * @param string $placement  | 
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| 106 | * @param array $data  | 
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| 107 | * @return int|false Id of new created node. False if node has not been created  | 
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| 108 | * @throws Exception  | 
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| 109 | */  | 
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| 110 | 18 | protected function addNode($targetNodeId, $placement, $data = array())  | 
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| 111 |     { | 
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| 112 | 18 | $adapter = $this->getAdapter();  | 
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| 113 | |||
| 114 | 18 | $adapter->beginTransaction();  | 
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| 115 |         try { | 
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| 116 | 18 | $targetNode = $adapter->getNodeInfo($targetNodeId);  | 
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| 117 | 18 |             if ($targetNode) { | 
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| 118 | 15 | $scope = $targetNode->getScope();  | 
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| 119 | 15 | $adapter->lockTree($scope);  | 
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| 120 | }  | 
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| 121 | |||
| 122 | 18 | $targetNode = $adapter->getNodeInfo($targetNodeId);  | 
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| 123 | |||
| 124 | 18 |             if (null == $targetNode) { | 
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| 125 | 3 | $adapter->commitTransaction();  | 
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| 126 | |||
| 127 | 3 | return false;  | 
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| 128 | }  | 
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| 129 | |||
| 130 | 15 | $addStrategy = $this->getAddStrategy($targetNode, $placement);  | 
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| 131 | |||
| 132 | 15 |             if (false == $addStrategy->canAddNewNode()) { | 
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| 133 | 6 | $adapter->commitTransaction();  | 
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| 134 | |||
| 135 | 6 | return false;  | 
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| 136 | }  | 
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| 137 | |||
| 138 | //make hole  | 
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| 139 | 15 | $moveFromIndex = $addStrategy->moveIndexesFromIndex();  | 
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| 140 | 15 | $adapter->moveLeftIndexes($moveFromIndex, 2, $targetNode->getScope());  | 
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| 141 | 15 | $adapter->moveRightIndexes($moveFromIndex, 2, $targetNode->getScope());  | 
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| 142 | |||
| 143 | //insert new node  | 
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| 144 | 15 | $newNodeInfo = new NodeInfo(  | 
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| 145 | 15 | null,  | 
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| 146 | 15 | $addStrategy->newParentId(),  | 
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| 147 | 15 | $addStrategy->newLevel(),  | 
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| 148 | 15 | $addStrategy->newLeftIndex(),  | 
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| 149 | 15 | $addStrategy->newRightIndex(),  | 
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| 150 | 15 | $targetNode->getScope()  | 
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| 151 | );  | 
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| 152 | 15 | $lastGeneratedValue = $adapter->insert($newNodeInfo, $data);  | 
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| 153 | |||
| 154 | 15 | $adapter->commitTransaction();  | 
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| 155 |         } catch (Exception $e) { | 
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| 156 | $adapter->rollbackTransaction();  | 
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| 157 | |||
| 158 | throw $e;  | 
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| 159 | }  | 
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| 160 | |||
| 161 | 15 | return $lastGeneratedValue;  | 
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| 162 | }  | 
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| 163 | |||
| 164 | /**  | 
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| 165 | * @param NodeInfo $targetNode  | 
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| 166 | * @param string $placement  | 
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| 167 | * @return AddStrategyInterface  | 
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| 168 | * @throws InvalidArgumentException  | 
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| 169 | */  | 
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| 170 | 15 | private function getAddStrategy(NodeInfo $targetNode, $placement)  | 
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| 171 |     { | 
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| 172 |         switch ($placement) { | 
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| 173 | 15 | case self::PLACEMENT_BOTTOM:  | 
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| 174 | 3 | return new AddStrategy\Bottom($targetNode);  | 
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| 175 | 12 | case self::PLACEMENT_TOP:  | 
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| 176 | 3 | return new AddStrategy\Top($targetNode);  | 
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| 177 | 9 | case self::PLACEMENT_CHILD_BOTTOM:  | 
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| 178 | 3 | return new AddStrategy\ChildBottom($targetNode);  | 
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| 179 | 6 | case self::PLACEMENT_CHILD_TOP:  | 
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| 180 | 6 | return new AddStrategy\ChildTop($targetNode);  | 
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| 181 | default:  | 
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| 182 |                 throw new InvalidArgumentException('Unknown placement "' . $placement . '"'); | 
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| 183 | }  | 
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| 184 | }  | 
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| 185 | |||
| 186 | 6 | public function addNodePlacementBottom($targetNodeId, $data = array())  | 
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| 190 | |||
| 191 | 3 | public function addNodePlacementTop($targetNodeId, $data = array())  | 
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| 195 | |||
| 196 | 3 | public function addNodePlacementChildBottom($targetNodeId, $data = array())  | 
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| 200 | |||
| 201 | 6 | public function addNodePlacementChildTop($targetNodeId, $data = array())  | 
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| 205 | |||
| 206 | /**  | 
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| 207 | * @param int $sourceNodeId  | 
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| 208 | * @param int $targetNodeId  | 
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| 209 | * @param string $placement  | 
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| 210 | * @return boolean  | 
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| 211 | * @throws Exception  | 
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| 212 | * @throws InvalidArgumentException  | 
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| 213 | */  | 
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| 214 | 21 | protected function moveNode($sourceNodeId, $targetNodeId, $placement)  | 
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| 215 |     { | 
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| 216 | 21 | $adapter = $this->getAdapter();  | 
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| 217 | |||
| 218 | //source node and target node are equal  | 
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| 219 | 21 |         if ($sourceNodeId == $targetNodeId) { | 
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| 220 | 3 | return false;  | 
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| 221 | }  | 
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| 222 | |||
| 223 | 21 | $adapter->beginTransaction();  | 
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| 224 |         try { | 
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| 225 | 21 | $sourceNode = $adapter->getNodeInfo($sourceNodeId);  | 
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| 226 | 21 |             if ($sourceNode) { | 
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| 227 | 21 | $scope = $sourceNode->getScope();  | 
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| 228 | 21 | $adapter->lockTree($scope);  | 
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| 229 | }  | 
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| 230 | |||
| 231 | 21 | $sourceNodeInfo = $adapter->getNodeInfo($sourceNodeId);  | 
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| 232 | 21 | $targetNodeInfo = $adapter->getNodeInfo($targetNodeId);  | 
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| 233 | |||
| 234 | //source node or target node does not exist  | 
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| 235 | 21 |             if (!$sourceNodeInfo || !$targetNodeInfo) { | 
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| 236 | 3 | $adapter->commitTransaction();  | 
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| 237 | |||
| 238 | 3 | return false;  | 
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| 239 | }  | 
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| 240 | |||
| 241 | // scope are different  | 
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| 242 | 21 |             if ($sourceNodeInfo->getScope() != $targetNodeInfo->getScope()) { | 
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| 243 | 3 |                 throw new InvalidArgumentException('Cannot move node between scopes'); | 
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| 244 | }  | 
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| 245 | |||
| 246 | 18 | $moveStrategy = $this->getMoveStrategy($sourceNodeInfo, $targetNodeInfo, $placement);  | 
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| 247 | |||
| 248 | 18 |             if (!$moveStrategy->canMoveBranch()) { | 
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| 249 | 9 | $adapter->commitTransaction();  | 
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| 250 | |||
| 251 | 9 | return false;  | 
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| 252 | }  | 
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| 253 | |||
| 254 | 15 |             if ($moveStrategy->isSourceNodeAtRequiredPosition()) { | 
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| 255 | 12 | $adapter->commitTransaction();  | 
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| 256 | |||
| 257 | 12 | return true;  | 
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| 258 | }  | 
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| 259 | |||
| 260 | //update parent id  | 
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| 261 | 15 | $newParentId = $moveStrategy->getNewParentId();  | 
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| 262 | 15 |             if ($sourceNodeInfo->getParentId() != $newParentId) { | 
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| 263 | 12 | $adapter->updateParentId($sourceNodeId, $newParentId);  | 
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| 264 | }  | 
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| 265 | |||
| 266 | //update levels  | 
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| 267 | 15 | $adapter->updateLevels($sourceNodeInfo->getLeft(), $sourceNodeInfo->getRight(),  | 
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| 268 | 15 | $moveStrategy->getLevelShift(), $sourceNodeInfo->getScope());  | 
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| 269 | |||
| 270 | //make hole  | 
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| 271 | 15 | $adapter->moveLeftIndexes($moveStrategy->makeHoleFromIndex(),  | 
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| 272 | 15 | $moveStrategy->getIndexShift(), $sourceNodeInfo->getScope());  | 
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| 273 | 15 | $adapter->moveRightIndexes($moveStrategy->makeHoleFromIndex(),  | 
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| 274 | 15 | $moveStrategy->getIndexShift(), $sourceNodeInfo->getScope());  | 
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| 275 | |||
| 276 | //move branch to the hole  | 
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| 277 | 15 | $adapter->moveBranch($moveStrategy->getHoleLeftIndex(), $moveStrategy->getHoleRightIndex(),  | 
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| 278 | 15 | $moveStrategy->getSourceNodeIndexShift(), $sourceNodeInfo->getScope());  | 
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| 279 | |||
| 280 | //patch hole  | 
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| 281 | 15 | $adapter->moveLeftIndexes($moveStrategy->fixHoleFromIndex(),  | 
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| 282 | 15 | ($moveStrategy->getIndexShift() * -1), $sourceNodeInfo->getScope());  | 
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| 283 | 15 | $adapter->moveRightIndexes($moveStrategy->fixHoleFromIndex(),  | 
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| 284 | 15 | ($moveStrategy->getIndexShift() * -1), $sourceNodeInfo->getScope());  | 
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| 285 | |||
| 286 | 15 | $adapter->commitTransaction();  | 
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| 287 | 3 |         } catch (Exception $e) { | 
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| 288 | 3 | $adapter->rollbackTransaction();  | 
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| 289 | |||
| 290 | 3 | throw $e;  | 
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| 291 | }  | 
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| 292 | |||
| 293 | 15 | return true;  | 
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| 294 | }  | 
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| 295 | |||
| 296 | 9 | public function moveNodePlacementBottom($sourceNodeId, $targetNodeId)  | 
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| 300 | |||
| 301 | 3 | public function moveNodePlacementTop($sourceNodeId, $targetNodeId)  | 
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| 305 | |||
| 306 | 6 | public function moveNodePlacementChildBottom($sourceNodeId, $targetNodeId)  | 
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| 310 | |||
| 311 | 3 | public function moveNodePlacementChildTop($sourceNodeId, $targetNodeId)  | 
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| 315 | |||
| 316 | /**  | 
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| 317 | * @param NodeInfo $sourceNode  | 
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| 318 | * @param NodeInfo $targetNode  | 
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| 319 | * @param string $placement  | 
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| 320 | * @return MoveStrategyInterface  | 
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| 321 | * @throws InvalidArgumentException  | 
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| 322 | */  | 
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| 323 | 18 | private function getMoveStrategy(NodeInfo $sourceNode, NodeInfo $targetNode, $placement)  | 
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| 324 |     { | 
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| 325 |         switch ($placement) { | 
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| 326 | 18 | case self::PLACEMENT_BOTTOM:  | 
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| 327 | 9 | return new MoveStrategy\Bottom($sourceNode, $targetNode);  | 
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| 328 | 9 | case self::PLACEMENT_TOP:  | 
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| 329 | 3 | return new MoveStrategy\Top($sourceNode, $targetNode);  | 
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| 330 | 6 | case self::PLACEMENT_CHILD_BOTTOM:  | 
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| 331 | 3 | return new MoveStrategy\ChildBottom($sourceNode, $targetNode);  | 
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| 332 | 3 | case self::PLACEMENT_CHILD_TOP:  | 
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| 333 | 3 | return new MoveStrategy\ChildTop($sourceNode, $targetNode);  | 
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| 334 | default:  | 
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| 335 |                 throw new InvalidArgumentException('Unknown placement "' . $placement . '"'); | 
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| 336 | }  | 
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| 337 | }  | 
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| 338 | |||
| 339 | 6 | public function deleteBranch($nodeId)  | 
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| 340 |     { | 
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| 341 | 6 | $adapter = $this->getAdapter();  | 
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| 342 | |||
| 343 | 6 | $adapter->beginTransaction();  | 
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| 344 |         try { | 
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| 345 | 6 | $node = $adapter->getNodeInfo($nodeId);  | 
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| 346 | 6 |             if ($node) { | 
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| 347 | 6 | $scope = $node->getScope();  | 
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| 348 | 6 | $adapter->lockTree($scope);  | 
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| 349 | }  | 
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| 350 | |||
| 351 | 6 | $nodeInfo = $adapter->getNodeInfo($nodeId);  | 
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| 352 | |||
| 353 | // node does not exist  | 
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| 354 | 6 |             if (!$nodeInfo) { | 
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| 355 | 3 | $adapter->commitTransaction();  | 
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| 356 | |||
| 357 | 3 | return false;  | 
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| 358 | }  | 
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| 359 | |||
| 360 | // delete branch  | 
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| 361 | 6 | $leftIndex = $nodeInfo->getLeft();  | 
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| 362 | 6 | $rightIndex = $nodeInfo->getRight();  | 
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| 363 | 6 | $adapter->delete($leftIndex, $rightIndex, $nodeInfo->getScope());  | 
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| 364 | |||
| 365 | //patch hole  | 
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| 366 | 6 | $moveFromIndex = $nodeInfo->getLeft();  | 
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| 367 | 6 | $shift = $nodeInfo->getLeft() - $nodeInfo->getRight() - 1;  | 
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| 368 | 6 | $adapter->moveLeftIndexes($moveFromIndex, $shift, $nodeInfo->getScope());  | 
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| 369 | 6 | $adapter->moveRightIndexes($moveFromIndex, $shift, $nodeInfo->getScope());  | 
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| 370 | |||
| 371 | 6 | $adapter->commitTransaction();  | 
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| 372 |         } catch (Exception $e) { | 
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| 373 | $adapter->rollbackTransaction();  | 
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| 374 | |||
| 375 | throw $e;  | 
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| 376 | }  | 
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| 377 | |||
| 378 | 6 | return true;  | 
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| 379 | }  | 
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| 380 | |||
| 381 | 6 | public function getPath($nodeId, $startLevel = 0, $excludeLastNode = false)  | 
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| 386 | |||
| 387 | 6 | public function getNode($nodeId)  | 
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| 392 | |||
| 393 | 9 | public function getDescendants($nodeId = 1, $startLevel = 0, $levels = null, $excludeBranch = null)  | 
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| 398 | |||
| 399 | 3 | public function getChildren($nodeId)  | 
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| 403 | |||
| 404 | 21 | public function getRootNode($scope = null)  | 
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| 409 | |||
| 410 | 3 | public function getRoots()  | 
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| 415 | |||
| 416 | 6 | public function isValid($rootNodeId)  | 
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| 421 | |||
| 422 | 3 | public function rebuild($rootNodeId)  | 
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| 427 | }  | 
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| 428 |