code: public Object getNextData() {
          moreData = false;
          if (dataObject instanceof double[][]) {
              return outputData;
          } else {
              throw new RuntimeException();
          }
      }
  
      public ColorMapBuffer getNextDataColor( int attColor ) {
          return null;
      }
  
      /**
       * Create a string that defines how the legend will look.
       * @throws IOException 
       */
      public String getLegendString() throws IOException {
          return null;
      }
  
      /**
       * 
       */
      public void hasChanged( boolean _haschanged ) {
          // if (_haschanged) {
          // novalue = new Double(Double.NaN);
          // matrixType = 0;
          // // theFilePath = null;
          // cellFile = nullFile = null;
          // filename = null;
          // mapsetPath = null;
          // locationPath = null;
          // rasterByteBuffer = null;
          // moreData = false;
          // // fileWindow = null;
          // // dataWindow = null;
          // rasterMapType = -9999;
          // numberOfBytesPerValue = -9999;
          // compressed = -9999;
          // }
          // hasChanged = _haschanged;
      }
docs: /*
  (non-Javadoc)
  
  @see jgrass.io.MapReader#getNextData() returns the data in the required format