/**
* Serialize the given event data as a standalone XML document
*
* @param includeProlog if true, include an XML prolog; if not, just render a document fragment
* @return the XML serialization, or null if <code>data</code> is null.
*/
public String serialize(EventDataElement data, boolean includeProlog) {
if (data == null || data.isNull()) return null;
try {
// serialize the DOM to our string buffer.
XMLStreamWriter writer = factory.createXMLStreamWriter(buffer);
try {
if (includeProlog) writer.writeStartDocument();
serializeElement(writer, data);
writer.writeEndDocument();
writer.flush();
} finally {
writer.close();
}
// return buffer contents.
return buffer.toString();
} catch (XMLStreamException ioe) {
// this shouldn't happen, since the target output stream is a StringWriter, but
// the compiler demands that we handle it.
throw new RuntimeException("Error serializing XML data", ioe);
} finally {
// reset the internal buffer for next run.
buffer.getBuffer().setLength(0);
}
}
/** Recursively serialize a single element, appending it to DOM element <code>parent</code>. */
protected void serializeElement(XMLStreamWriter writer, EventDataElement element)
throws XMLStreamException {
if (!element.isNull()) {
// create a new node for the element and append it to the parent.
String name = getXMLElementName(element.getName());
if (element.isEmpty()) {
writer.writeEmptyElement(name);
// TODO: remove when stax bug is fixed.
// this is a workaround for a bug in the 1.2 StAX implementation, where
// if the only element in your document is empty, the closing "/>" never gets written.
// any other API call fixes the problem, so here we do a no-op string append to force
// the element closed.
writer.writeCharacters(DUMMY_TEXT, 0, 0);
} else {
writer.writeStartElement(name);
// add attributes for properties.
Iterator<? extends Entry<String, Object>> props = element.iterateProperties();
while (props.hasNext()) {
Entry<String, Object> prop = props.next();
Object value = prop.getValue();
if (value != null) {
String propName = getXMLElementName(prop.getKey());
writer.writeAttribute(propName, value.toString());
}
}
// add text to the element if applicable.
String text = element.getText();
if (text != null) writer.writeCharacters(text);
// add child elements for children.
Iterator<EventDataElement> children = element.iterateChildren();
while (children.hasNext()) serializeElement(writer, children.next());
writer.writeEndElement();
}
}
}
