code: public boolean containsExcludeResultPrefix(String prefix, String uri)
    {
      if (uri == null ||
                  (null == m_excludeResultPrefixes &&
                   null == m_ExtensionElementURIs)
                  )
        return super.containsExcludeResultPrefix(prefix, uri);
  
      if (prefix.length() == 0)
        prefix = Constants.ATTRVAL_DEFAULT_PREFIX;
  
      // This loop is ok here because this code only runs during
      // stylesheet compile time.    
          if(m_excludeResultPrefixes!=null)
              for (int i =0; i< m_excludeResultPrefixes.size(); i++)
              {
                  if (uri.equals(getNamespaceForPrefix(m_excludeResultPrefixes.elementAt(i))))
                      return true;
              }    
          
          // JJK Bugzilla 1133: Also check locally-scoped extensions
      if(m_ExtensionElementURIs!=null && m_ExtensionElementURIs.contains(uri))
         return true;
  
          return super.containsExcludeResultPrefix(prefix, uri);
    }
docs: Get whether or not the passed URL is flagged by
  the "extension-element-prefixes" or "exclude-result-prefixes"
  properties.
  @see <a href="http://www.w3.org/TR/xslt#extension-element">extension-element in XSLT Specification</a>
  
  @param prefix non-null reference to prefix that might be excluded.(not currently used)
  @param uri reference to namespace that prefix maps to
  
  @return true if the prefix should normally be excluded.