question: public static boolean isDefinedNSDecl ( SerializationHandler serializer , int attr , DTM dtm ) { if ( DTM . NAMESPACE_NODE == dtm . getNodeType ( attr ) ) { String prefix = dtm . getNodeNameX ( attr ) ; String uri = serializer . getNamespaceURIFromPrefix ( prefix ) ; if ( ( null != uri ) && uri . equals ( dtm . getStringValue ( attr ) ) ) return true ; } return false ; }
target:  Returns whether a namespace is defined