/**
  * @throws Exception
  */
 public function beforeUpdate()
 {
     if ($this->node !== null && !$this->node->getIsNewRecord()) {
         $this->node->refresh();
     }
     switch ($this->operation) {
         case self::OPERATION_MAKE_ROOT:
             if ($this->treeAttribute === null) {
                 throw new Exception('Can not move a node as the root when "treeAttribute" is not set.');
             }
             if ($this->isRoot()) {
                 throw new Exception('Can not move the root node as the root.');
             }
             break;
         case self::OPERATION_INSERT_BEFORE:
         case self::OPERATION_INSERT_AFTER:
             if ($this->node->isRoot()) {
                 throw new Exception('Can not move a node before/after root.');
             }
         case self::OPERATION_PREPEND_TO:
         case self::OPERATION_APPEND_TO:
             if ($this->node->getIsNewRecord()) {
                 throw new Exception('Can not move a node when the target node is new record.');
             }
             if ($this->owner->equals($this->node)) {
                 throw new Exception('Can not move a node when the target node is same.');
             }
             if ($this->node->isChildOf($this->owner)) {
                 throw new Exception('Can not move a node when the target node is child.');
             }
     }
 }
 /**
  * @param bool $forInsertNear
  * @throws Exception
  */
 protected function checkNode($forInsertNear = false)
 {
     if ($forInsertNear && $this->node->isRoot()) {
         throw new Exception('Can not move a node before/after root.');
     }
     if ($this->node->getIsNewRecord()) {
         throw new Exception('Can not move a node when the target node is new record.');
     }
     if ($this->owner->equals($this->node)) {
         throw new Exception('Can not move a node when the target node is same.');
     }
     if ($this->checkLoop && $this->node->isChildOf($this->owner)) {
         throw new Exception('Can not move a node when the target node is child.');
     }
 }
 /**
  * @throws Exception
  */
 public function beforeUpdate()
 {
     if ($this->node !== null && !$this->node->getIsNewRecord()) {
         $this->node->refresh();
     }
     switch ($this->operation) {
         case self::OPERATION_MAKE_ROOT:
             if ($this->treeAttribute === false) {
                 throw new Exception('Can not move a node as the root when "treeAttribute" is false.');
             }
             if ($this->owner->isRoot()) {
                 throw new Exception('Can not move the root node as the root.');
             }
             if (!$this->treeAttributeById) {
                 if ($this->owner->getOldAttribute($this->treeAttribute) === $this->owner->getAttribute($this->treeAttribute)) {
                     throw new Exception('Can not move a node as the root when its tree attribute "' . $this->treeAttribute . '" is not changed.');
                 }
                 if ($this->owner->find()->andWhere([$this->treeAttribute => $this->owner->getAttribute($this->treeAttribute), $this->leftAttribute => 1])->one()) {
                     throw new Exception('Can not move a node as the root when another root with this "' . $this->treeAttribute . '" already exists.');
                 }
             }
             break;
         case self::OPERATION_INSERT_BEFORE:
         case self::OPERATION_INSERT_AFTER:
             if ($this->node->isRoot()) {
                 throw new Exception('Can not move a node when the target node is root.');
             }
         case self::OPERATION_PREPEND_TO:
         case self::OPERATION_APPEND_TO:
             if ($this->node->getIsNewRecord()) {
                 throw new Exception('Can not move a node when the target node is new record.');
             }
             if ($this->owner->equals($this->node)) {
                 throw new Exception('Can not move a node when the target node is same.');
             }
             if ($this->node->isChildOf($this->owner)) {
                 throw new Exception('Can not move a node when the target node is child.');
             }
     }
 }