public boolean initialize(){
		if( is_init )
			return true;
		if( !dao_state.initialize() ){
			System.out.println( "LocationHandler : failed to initialize PersonStateDao!" );
			return false;
		}
		if( !dao_area.initialize() ){
			System.out.println( "LocationHandler : failed to initialize LocationAreaDao!" );
			dao_state.closeDatabase();
			return false;
		}
		if( !dao_node.initialize() ){
			System.out.println( "LocationHandler : failed to initialize LocationNodeDao!" );
			dao_state.closeDatabase();
			dao_area.closeDatabase();
			return false;
		}
		is_init = true;
		return true;
	}