Singleton to instantiate Neo4j

gistfile1.scala

object Database extends Logging {

  private var _instance: GraphDatabaseService = null

  def instance: GraphDatabaseService = {
    if (null == _instance) {
      synchronized {
        if (null == _instance) {
          _instance = initDatabase()
        }
      }
    }

    _instance
  }

  protected def initDatabase: GraphDatabaseService = {
    logger.info("Starting neo4j init procedure")

    val inst = new GraphDatabaseFactory()
        .newEmbeddedDatabaseBuilder(ProjectProperties.get("neo.db_path"))
        .newGraphDatabase()
        
    sys.addShutdownHook(inst.shutdown())

    inst
  }

}