code: private String _serializeStruct(Struct struct, Map<Object, String> done, String id) throws ConverterException {
  	StringBuilder sb = new StringBuilder(goIn() + "<STRUCT ID=\"" + id + "\">");
  
  	Iterator<Key> it = struct.keyIterator();
  
  	deep++;
  	while (it.hasNext()) {
  	    Key key = it.next();
  	    // <ENTRY NAME="STRING" TYPE="STRING">hello</ENTRY>
  	    String value = _serialize(struct.get(key, null), done);
  	    sb.append(goIn() + "<ENTRY NAME=\"" + key.toString() + "\" TYPE=\"" + type + "\">");
  	    sb.append(value);
  	    sb.append(goIn() + "</ENTRY>");
  	}
  	deep--;
  
  	sb.append(goIn() + "</STRUCT>");
  	type = "STRUCT";
  	return sb.toString();
      }
docs: serialize a Struct
  
  @param struct Struct to serialize
  @param done
  @return serialized struct
  @throws ConverterException