public void setPrefix(final String prefix) {
        if ((this.prefix != null && !this.prefix.equals(prefix)) || (prefix != null && !prefix.equals(this.prefix))) {
            if (prefix != null) {
                this.prefix = prefix;
            } else {
                this.prefix = null;
            }

            // Update the qName.
            qName = createQName();
        }
    }
@param prefix the prefix to set.
stroom-pipeline/src/main/java/stroom/pipeline/xml/event/simple/StartElement.java