public int length(){
		if(root.child==null){
			return 0;
		}
		if(length>-1){
			return length;
		}
		length=root.getChildCount();
		return length;
	}
public int length ( ) { if ( root . child == null ) { return 0 ; } if ( length > - 1 ) { return length ; } length = root . getChildCount ( ) ; return length ; }
Returns the number of fields on this object

@return the number of fields