* @param objectKey key pointing to the object
* @return form-open element for a nested resource object
*/
public static String formForOpen(String parentResourceName,
String parentObjectKey, String resourceName, String objectKey) {
RESTified parentRecord = getAndValidateObject(parentResourceName, parentObjectKey);
RESTified object = getAndValidateObject(resourceName, objectKey);
storeObjectToCurrentCache(object);
storeObjectKeyToCurrentCache(objectKey);
return R.formForNestedResourceRecord(parentResourceName, parentRecord, resourceName, object);
}