How to use

visit

method

in

org.geotools.styling.StyleAttributeExtractor

public Object visit(org.opengis.filter.expression.Function expression, Object data) {
  usingVolatileFunctions |= (expression instanceof VolatileFunction);
  return super.visit(expression, data);
};

/**
 * @see org.geotools.styling.StyleVisitor#visit(org.geotools.styling.Symbolizer)
 */
public void visit(Symbolizer sym) {
  if (sym instanceof PointSymbolizer) {
    visit((PointSymbolizer) sym);
  }
  if (sym instanceof LineSymbolizer) {
    visit((LineSymbolizer) sym);
  }
  if (sym instanceof PolygonSymbolizer) {
    visit((PolygonSymbolizer) sym);
  }
  if (sym instanceof TextSymbolizer) {
    visit((TextSymbolizer) sym);
  }
  if (sym instanceof RasterSymbolizer) {
    visit((RasterSymbolizer) sym);
  }
}

/**
 * @see org.geotools.styling.StyleVisitor#visit(org.geotools.styling.Symbolizer)
 */
public void visit(Symbolizer sym) {
  if (sym instanceof PointSymbolizer) {
    visit((PointSymbolizer) sym);
  }
  if (sym instanceof LineSymbolizer) {
    visit((LineSymbolizer) sym);
  }
  if (sym instanceof PolygonSymbolizer) {
    visit((PolygonSymbolizer) sym);
  }
  if (sym instanceof TextSymbolizer) {
    visit((TextSymbolizer) sym);
  }
  if (sym instanceof RasterSymbolizer) {
    visit((RasterSymbolizer) sym);
  }
}

  public void visit( Rule rule ) {
    DuplicatingStyleVisitor dupeStyleVisitor = new DuplicatingStyleVisitor();
    dupeStyleVisitor.visit(rule);
    Rule clone = (Rule) dupeStyleVisitor.getCopy();
    super.visit(clone);
  }
};

rulesLength = rules.length;
for (int j = 0; j < rulesLength; j++) {
  sae.visit(rules[j]);
  sae.visit(rules[j]);

/**
 * 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]);
}

/**
 * Checks to make sure that the style passed in can process the FeatureType.
 * 
 * @param style
 *            The style to check
 * @param fType
 *            The source requested.
 * 
 * @throws WmsException
 *             DOCUMENT ME!
 */
private void checkStyle(Style style, SimpleFeatureType fType) throws WmsException {
  StyleAttributeExtractor sae = new StyleAttributeExtractor();
  sae.visit(style);
  String[] styleAttributes = sae.getAttributeNames();
  String attName;
  final int length = styleAttributes.length;
  for (int i = 0; i < length; i++) {
    attName = styleAttributes[i];
    if (fType.getDescriptor(attName) == null) {
      throw new WmsException(
          "The requested Style can not be used with "
              + "this featureType.  The style specifies an attribute of "
              + attName
              + " and the featureType definition is: "
              + fType);
    }
  }
}

/**
 * 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]);
}

rulesLength = rules.length;
for (int j = 0; j < rulesLength; j++) {
  sae.visit(rules[j]);
  sae.visit(rules[j]);

sae.visit(style);
String[] styleAttributes = sae.getAttributeNames();

sae.visit(style);
Set<PropertyName> styleAttributes = sae.getAttributes();