How to use

getAttributeNameSet

method

in

org.geotools.styling.StyleAttributeExtractor

/**
 * Inspects the <code>MapLayer</code>'s style and retrieves it's needed attribute names,
 * returning at least the default geometry attribute name.
 * 
 * @param query DOCUMENT ME!
 * @param style the <code>Style</code> to determine the needed attributes from
 * @param schema the featuresource schema
 * @return the minimun set of attribute names needed to render <code>layer</code>
 */
private String[] findStyleAttributes( final Query query, Style style, FeatureType schema ) {
  StyleAttributeExtractor sae = new StyleAttributeExtractor(){
    public void visit( Rule rule ) {
      DuplicatingStyleVisitor dupeStyleVisitor = new DuplicatingStyleVisitor();
      dupeStyleVisitor.visit(rule);
      Rule clone = (Rule) dupeStyleVisitor.getCopy();
      super.visit(clone);
    }
  };
  sae.visit(style);
  
  FilterAttributeExtractor qae = new FilterAttributeExtractor();
  query.getFilter().accept(qae,null);
  Set ftsAttributes=new HashSet(sae.getAttributeNameSet());
  ftsAttributes.addAll(qae.getAttributeNameSet());
  // the code following assumes we won't extract the default geometry, and that's
  // most of the time true, but fails if the filter or the style uses it.
  ftsAttributes.remove(schema.getDefaultGeometry().getLocalName());
  return (String[]) ftsAttributes.toArray(new String[0]);
}

/**
 * Inspects the <code>MapLayer</code>'s style and retrieves it's needed attribute names,
 * returning at least the default geometry attribute name.
 * 
 * @param query DOCUMENT ME!
 * @param style the <code>Style</code> to determine the needed attributes from
 * @param schema the SimpleFeatureSource schema
 * @return the minimun set of attribute names needed to render <code>layer</code>
 */
private String[] findStyleAttributes( final Query query, Style style, SimpleFeatureType schema ) {
  StyleAttributeExtractor sae = new StyleAttributeExtractor();
  sae.visit(style);
  
  FilterAttributeExtractor qae = new FilterAttributeExtractor();
  query.getFilter().accept(qae,null);
  Set ftsAttributes = new LinkedHashSet(sae.getAttributeNameSet());
  ftsAttributes.addAll(qae.getAttributeNameSet());
  if (sae.getDefaultGeometryUsed()
      && (!ftsAttributes.contains(schema.getGeometryDescriptor().getLocalName()))) {
    ftsAttributes.add(schema.getGeometryDescriptor().getLocalName());
  } else {
    // the code following assumes the geometry column is the last one
    // make sure it's the last for good
    ftsAttributes.remove(schema.getGeometryDescriptor().getLocalName());
    ftsAttributes.add(schema.getGeometryDescriptor().getLocalName());
  }
  return (String[]) ftsAttributes.toArray(new String[0]);
}

extractor.clear();
g.accept(extractor, null);
Set<String> attributes = extractor.getAttributeNameSet();
for (String attribute : attributes) {
  if(plainGeometries.contains(attribute))

Set<String> attributeNames = sae.getAttributeNameSet();

style.accept(atts);
assertTrue(atts.getAttributeNameSet().contains("CAT_ID"));