code: public String getExtensionElementPrefix(int i)
            throws ArrayIndexOutOfBoundsException
    {
  
      if (null == m_ExtensionElementURIs)
        throw new ArrayIndexOutOfBoundsException();
  
      return m_ExtensionElementURIs.elementAt(i);
    }
docs: Get an "extension-element-prefix" property.
  @see <a href="http://www.w3.org/TR/xslt#extension-element">extension-element in XSLT Specification</a>
  
  @param i Index of URI ("extension-element-prefix" property) to get
  
  @return URI at given index ("extension-element-prefix" property)
  
  @throws ArrayIndexOutOfBoundsException