@Override
    public String getURI(final int index) {
        if (index >= 0 && index < length) {
            return data[index * 5];
        } else {
            return null;
        }
    }
Return an attribute's Namespace URI.

@param index The attribute's index (zero-based).
@return The Namespace URI, the empty string if none is available, or null
if the index is out of range.
@see org.xml.sax.Attributes#getURI
stroom-pipeline/src/main/java/stroom/pipeline/xml/event/simple/AttributesImpl.java