public OMElement serialize(OMElement parent) {
OMElement eventElement = fac.createOMElement("event", synNS);
ValueSerializer vs = new ValueSerializer();
if (getTopic() != null) {
vs.serializeValue(getTopic(), "topic", eventElement);
}
if (getExpression() != null) {
SynapseXPathSerializer.serializeXPath(getExpression(),
eventElement, "expression");