public String lookupPrefix(String uri){
  String foundPrefix=null;
  Enumeration prefixes=m_namespaces.keys();
  while (prefixes.hasMoreElements()) {
    String prefix=(String)prefixes.nextElement();
    String uri2=lookupNamespace(prefix);
    if (uri2 != null && uri2.equals(uri)) {
      foundPrefix=prefix;
      break;
    }
  }
  return foundPrefix;
}

public String lookupPrefix ( String uri ) { String foundPrefix = null ; Enumeration prefixes = m_namespaces . keys ( ) ; while ( prefixes . hasMoreElements ( ) ) { String prefix = ( String ) prefixes . nextElement ( ) ; String uri2 = lookupNamespace ( prefix ) ; if ( uri2 != null && uri2 . equals ( uri ) ) { foundPrefix = prefix ; break ; } } return foundPrefix ; }
given a namespace uri , and the namespaces mappings for the current element , return the current prefix for that uri .
