How to use

visitCqlExpression

method

in

org.geotools.styling.StyleAttributeExtractor

/**
 * @see org.geotools.styling.StyleVisitor#visit(org.geotools.styling.ExternalGraphic)
 */
public void visit(ExternalGraphic exgr) {
  // add dynamic support for ExternalGrapic format attribute
  visitCqlExpression(exgr.getFormat());
  try {
    if(exgr.getLocation() != null)
      visitCqlExpression(exgr.getLocation().toString());
  } catch(MalformedURLException e) {
    throw new RuntimeException("Errors while inspecting " +
        "the location of an external graphic", e);
  }
}

/**
 * @see org.geotools.styling.StyleVisitor#visit(org.geotools.styling.Mark)
 */
public void visit(Mark mark) {
  if (mark.getFill() != null) {
    mark.getFill().accept(this);
  }
  if (mark.getStroke() != null) {
    mark.getStroke().accept(this);
  }
  
  if(mark.getWellKnownName() != null) {
    if(mark.getWellKnownName() instanceof Literal) {
      visitCqlExpression(mark.getWellKnownName().evaluate(null, String.class));
    } else {
      mark.getWellKnownName().accept(this,null);
    }
  }
}