public String loadSymbolTypes()
     throws ClassNotFoundException, InstantiationException, IllegalAccessException {
   StringBuffer buffer = new StringBuffer();
   String[] symbolTypeNames = getListFromProperties(SYMBOL_TYPES);
   if (symbolTypeNames != null) {
     buffer.append("\tCustom symbol types loaded:").append(endl);
     for (String symbolTypeName : symbolTypeNames) {
       Class<?> symbolTypeClass = Class.forName(symbolTypeName.trim());
       symbolProvider.add((SymbolType) symbolTypeClass.newInstance());
       buffer.append("\t\t").append(symbolTypeClass.getName()).append(endl);
     }
   }
   return buffer.toString();
 }
 public static void registerSymbolTypes(SymbolProvider provider) {
   provider.add(new Today());
 }
 public void registerSymbolTypes(SymbolProvider symbolProvider) throws PluginException {
   symbolProvider.add(GraphvizDotSymbol.make(properties));
 }