protected abstract IndexColorModel filter(RasterOp imageOperation, Map requestParameter, IndexColorModel source);
public IndexColorModel filter(Map requestParameter, IndexColorModel source, BufferedImage sourceImage) { RasterOp imageOperation;  if (requestParameter.isEmpty() == false && ignoreRequestParameter() == false) { imageOperation = getImageOperation(sourceImage, requestParameter);  } else { imageOperation = this.imageOperation; }  if (imageOperation == null) { return source; }  return filter(imageOperation, requestParameter, source); }
    protected abstract IndexColorModel filter(RasterOp imageOperation,            Map requestParameter, IndexColorModel source);