function refresh(this)
%REFRESH Refresh stem plot
  
%   Copyright 1984-2004 The MathWorks, Inc.

is3D = ~isempty(this.zdata);

if ~strcmp(this.dirty,'clean')
  if length(this.xdata) ~= length(this.ydata)
    this.dirty = 'inconsistent';
  else
    % force data to be column vector
    [x,y] = deal(this.xdata,this.ydata);
    x = x(:); y = y(:);
    if is3D 
      z = this.zdata; z = z(:); 
    end
      
    % Create data for plotting stem marker and stem line. 
    % NaNs are used to make non-continuos line segments.
    m = length(x);
    xx = zeros(3*m,1);
    xx(1:3:3*m) = x;
    xx(2:3:3*m) = x;
    xx(3:3:3*m) = NaN;
    
    if is3D
       yy = zeros(3*m,1);
       yy(1:3:3*m) = y;
       yy(2:3:3*m) = y;
       yy(3:3:3*m) = NaN;

       zz = this.basevalue*ones(3*m,1);
       zz(1:3:3*m) = z;
       zz(3:3:3*m) = NaN;     
    else         
       yy = this.basevalue*ones(3*m,1);
       yy(2:3:3*m) = y;
       yy(3:3:3*m) = NaN;
       
       zz = [];
       z = [];
    end     
    
    hMarker = get(this,'MarkerHandle');
    hStem = get(this,'StemHandle');
    set([hMarker,hStem],'Visible',this.visible);
    
    % stem marker
    set(hMarker,'xdata',x,'ydata',y,'zdata',z);
    % stem line
    set(hStem,'xdata',xx,'ydata',yy,'zdata',zz);

    cax = get(this,'Parent');
    if ~strcmp(get(cax,'Type'),'axes')
      cax = ancestor(cax,'axes');
    end
    if ~ishold(cax)
      set(cax,'Box','on');
    end
    this.dirty = 'clean';
    update(this);
    if ~isempty(getappdata(double(this),'LegendLegendInfo'))
      setLegendInfo(this);
    end
  end
end