protected function loadExecution($executionId)
 {
     if (!is_int($executionId)) {
         throw new \ezcWorkflowExecutionException("Execution-Id has to be an integer (strictly-typed).");
     }
     $sql = 'SELECT * FROM ' . $this->options->executionTable() . ' WHERE execution_id = ?';
     $stmt = $this->conn->prepare($sql);
     $stmt->bindParam(1, $executionId);
     $stmt->execute();
     $result = $stmt->fetchAll(\PDO::FETCH_ASSOC);
     if ($result === false || empty($result)) {
         throw new \ezcWorkflowExecutionException('Could not load execution state for ID ' . (int) $executionId);
     }
     $execution = array_change_key_case($result[0], \CASE_LOWER);
     $this->id = (int) $execution['execution_id'];
     $this->nextThreadId = $execution['execution_next_thread_id'];
     $serializer = $this->options->getSerializer();
     $this->variables = $serializer->unserialize($execution['execution_variables']);
     $this->waitingFor = $serializer->unserialize($execution['execution_waiting_for']);
     $this->threads = $serializer->unserialize($execution['execution_threads']);
     $this->workflow = $this->definitionStorage->loadById($execution['workflow_id']);
     $sql = 'SELECT * FROM ' . $this->options->executionStateTable() . ' WHERE execution_id = ?';
     $stmt = $this->conn->prepare($sql);
     $stmt->bindParam(1, $executionId);
     $stmt->execute();
     $result = $stmt->fetchAll(\PDO::FETCH_ASSOC);
     $active = array();
     foreach ($result as $row) {
         $row = array_change_key_case($row, \CASE_LOWER);
         $active[$row['node_id']] = array('activated_from' => $serializer->unserialize($row['node_activated_from']), 'state' => $serializer->unserialize($row['node_state'], null), 'thread_id' => $row['node_thread_id']);
     }
     foreach ($this->workflow->nodes as $node) {
         $nodeId = $node->getId();
         if (isset($active[$nodeId])) {
             $node->setActivationState(\ezcWorkflowNode::WAITING_FOR_EXECUTION);
             $node->setThreadId($active[$nodeId]['thread_id']);
             $node->setState($active[$nodeId]['state'], null);
             $node->setActivatedFrom($active[$nodeId]['activated_from']);
             $this->activate($node, false);
         }
     }
     $this->cancelled = false;
     $this->ended = false;
     $this->loaded = true;
     $this->resumed = false;
     $this->suspended = true;
 }
 /**
  * Save a workflow definition to the database.
  *
  * @param  ezcWorkflow $workflow
  * @throws ezcWorkflowDefinitionStorageException
  */
 public function save(\ezcWorkflow $workflow)
 {
     // Verify the workflow.
     $workflow->verify();
     if (strlen($workflow->name) == 0) {
         throw new \ezcWorkflowDefinitionStorageException();
     }
     $platform = $this->conn->getDatabasePlatform();
     // what mode of saving should it be? Update or Re-Generate?
     //
     // Conditions that an update sufficies:
     // 1. No node has been deleted
     // 2. No node has changed its meaning (action class or type)
     // 3. For simplicitly only zero or one new nodes will be created.
     $hasExistingNodeIds = array();
     $newNodes = 0;
     foreach ($workflow->nodes as $node) {
         $oid = spl_object_hash($node);
         if (!isset($this->nodeMap[$oid])) {
             $newNodes++;
         } else {
             $hasExistingNodeIds[] = $this->nodeMap[$oid];
         }
     }
     $canBeUpdate = false;
     if ($newNodes < 2 && count(array_diff($hasExistingNodeIds, $this->workflowNodeIds[$workflow->id])) == 0 && $workflow->id) {
         $canBeUpdate = true;
     }
     $this->workflowNodeIds[$workflow->id] = array();
     try {
         $this->conn->beginTransaction();
         $workflowVersion = $this->getCurrentVersion($workflow->name) + 1;
         $this->conn->update($this->options->workflowTable(), array('workflow_outdated' => 1), array('workflow_name' => $workflow->name));
         $date = new \DateTime("now");
         if ($canBeUpdate) {
             $this->conn->update($this->options->workflowTable(), array('workflow_version' => $workflowVersion, 'workflow_created' => $date->format($platform->getDateTimeFormatString())), array('workflow_id' => $workflow->id));
         } else {
             $data = array('workflow_name' => $workflow->name, 'workflow_version' => $workflowVersion, 'workflow_created' => $date->format($platform->getDateTimeFormatString()), 'workflow_outdated' => 0);
             // For sequences: get id before insert
             if ($platform->prefersSequences()) {
                 $id = (int) $this->conn->fetchColumn($platform->getSequenceNextValSQL($this->options->workflowSequence()));
                 $data['workflow_id'] = $id;
                 $workflow->id = $id;
             }
             $this->conn->insert($this->options->workflowTable(), $data);
             if ($platform->prefersIdentityColumns()) {
                 $workflow->id = (int) $this->conn->lastInsertId();
             }
             $workflow->definitionStorage = $this;
         }
         // Write node table rows.
         $nodeMap = array();
         foreach ($workflow->nodes as $node) {
             /* @var $node \ezcWorkflowNode */
             $oid = spl_object_hash($node);
             if ($canBeUpdate && isset($this->nodeMap[$oid])) {
                 $nodeId = (int) $this->nodeMap[$oid];
                 $this->conn->update($this->options->nodeTable(), array('node_configuration' => $this->options->getSerializer()->serialize($node->getConfiguration())), array('node_id' => $nodeId));
             } else {
                 $data = array('workflow_id' => (int) $workflow->id, 'node_class' => get_class($node), 'node_configuration' => $this->options->getSerializer()->serialize($node->getConfiguration()));
                 if ($platform->prefersSequences()) {
                     $nodeId = (int) $this->conn->fetchColumn($platform->getSequenceNextValSQL($this->options->nodeSequence()));
                     $data['node_id'] = $nodeId;
                 }
                 $this->conn->insert($this->options->nodeTable(), $data);
                 if ($platform->prefersIdentityColumns()) {
                     $nodeId = (int) $this->conn->lastInsertId();
                 }
             }
             $nodeMap[$nodeId] = $node;
             $this->workflowNodeIds[$workflow->id][] = $nodeId;
             $this->nodeMap[$oid] = $nodeId;
         }
         if ($canBeUpdate) {
             // Delete all the node connections, NodeMap Keys are casted to (int) so usage here is safe.
             $query = "DELETE FROM " . $this->options->nodeConnectionTable() . " " . "WHERE incoming_node_id IN (" . implode(",", array_keys($nodeMap)) . ") OR " . "outgoing_node_id IN (" . implode(",", array_keys($nodeMap)) . ")";
             $this->conn->executeUpdate($query);
         }
         foreach ($workflow->nodes as $node) {
             foreach ($node->getOutNodes() as $outNode) {
                 $incomingNodeId = null;
                 $outgoingNodeId = null;
                 foreach ($nodeMap as $_id => $_node) {
                     if ($_node === $node) {
                         $incomingNodeId = $_id;
                     } else {
                         if ($_node === $outNode) {
                             $outgoingNodeId = $_id;
                         }
                     }
                     if ($incomingNodeId !== NULL && $outgoingNodeId !== NULL) {
                         break;
                     }
                 }
                 $data = array('incoming_node_id' => $incomingNodeId, 'outgoing_node_id' => $outgoingNodeId);
                 if ($platform->prefersSequences()) {
                     $id = (int) $this->conn->fetchColumn($platform->getSequenceNextValSQL($this->options->nodeConnectionSequence()));
                     $data['id'] = $id;
                 }
                 $this->conn->insert($this->options->nodeConnectionTable(), $data);
             }
         }
         unset($nodeMap);
         if ($canBeUpdate) {
             $this->conn->delete($this->options->variableHandlerTable(), array('workflow_id' => (int) $workflow->id));
         }
         foreach ($workflow->getVariableHandlers() as $variable => $class) {
             $this->conn->insert($this->options->variableHandlerTable(), array('workflow_id' => (int) $workflow->id, 'variable' => $variable, 'class' => $class));
         }
         $this->conn->commit();
     } catch (\Exception $e) {
         $this->conn->rollBack();
         throw new \ezcWorkflowDefinitionStorageException("Error while persisting workflow: " . $e->getMessage());
     }
 }