* Receives the value of the ODFDOM attribute representation <code>TextProtectionKeyAttribute</code> , See {@odf.attribute text:protection-key}
*
* @return - the <code>String</code> , the value or <code>null</code>, if the attribute is not set and no default value defined.
*/
public String getTextProtectionKeyAttribute() {
TextProtectionKeyAttribute attr = (TextProtectionKeyAttribute) getOdfAttribute(OdfDocumentNamespace.TEXT, "protection-key");
if (attr != null) {
return String.valueOf(attr.getValue());
}
return null;
}