/** {@inheritDoc} */
  @Override
  public Requisition addNewNodeToGroup(final String groupName, final String nodeLabel) {
    m_writeLock.lock();

    try {
      final Requisition group = getProvisioningGroup(groupName);

      final RequisitionNode node =
          createNode(nodeLabel, String.valueOf(System.currentTimeMillis()));
      node.setBuilding(groupName);
      group.insertNode(node);

      m_pendingForeignSourceRepository.save(group);
      m_pendingForeignSourceRepository.flush();
      return m_pendingForeignSourceRepository.getRequisition(groupName);
    } finally {
      m_writeLock.unlock();
    }
  }