# File lib/graphviz/graphml.rb, line 38
    def initialize( file_or_str )
      data = ((File.file?( file_or_str )) ? File::new(file_or_str) : file_or_str) 
      @xmlDoc = REXML::Document::new( data )
      @attributs = {
        :nodes => {},
        :edges => {},
        :graphs => {}
      }
      @graph = nil
      @current_attr = nil
      @current_node = nil
      @current_edge = nil
      @current_graph = nil
      
      parse( @xmlDoc.root )
    end