question: protected void ensureUnsignedProperties ( ) throws DSSException { final NodeList qualifyingPropertiesNodeList = currentSignatureDom . getElementsByTagNameNS ( XAdESNamespaces . XAdES , "QualifyingProperties" ) ; if ( qualifyingPropertiesNodeList . getLength ( ) != 1 ) { throw new DSSException ( "The signature does not contain QualifyingProperties element (or contains more than one)! Extension is not possible." ) ; } qualifyingPropertiesDom = ( Element ) qualifyingPropertiesNodeList . item ( 0 ) ; final NodeList unsignedPropertiesNodeList = currentSignatureDom . getElementsByTagNameNS ( XAdESNamespaces . XAdES , "UnsignedProperties" ) ; final int length = unsignedPropertiesNodeList . getLength ( ) ; if ( length == 1 ) { unsignedPropertiesDom = ( Element ) qualifyingPropertiesNodeList . item ( 0 ) ; } else if ( length == 0 ) { unsignedPropertiesDom = DSSXMLUtils . addElement ( documentDom , qualifyingPropertiesDom , XAdESNamespaces . XAdES , "xades:UnsignedProperties" ) ; } else { throw new DSSException ( "The signature contains more then one UnsignedProperties element! Extension is not possible." ) ; } }
target:  Returns or creates (if it does not exist) the UnsignedPropertiesType DOM object.