String cacheId = req.getParameter("cache_id");
String nameInEmail = req.getParameter("name_in_email");
 
// find EmailMessage by cache_id
EmailMessage emailMessage = emailMessageService.findBy(cacheId);
 
// find BroadcastReceiverChannelDestination by channel, broadcast_id, destination, receiver_id
BroadcastReceiverChannelDestination brcd = brcdService.findBy("EMAIL", emailMessage.getBroadcast().getId(), emailMessage.getReceiverEmail(), emailMessage.getReceiver().getId());
 
// get current BroadcastResponseOption of user
BroadcastResponseOption curRespOpt = brcd.getResponse();
 
// find BroadcastResponseOption by broadcast_id and name_in_email (received BroadcastResponseOption from user)
BroadcastResponseOption newRespOpt = broadcastResponseOptionService.findBy(emailMessage.getBroadcast().getId(), nameInEmail);
 
// detect ResponseMessageTemplateType
ResponseMessageTemplateType respType;
if (broadcast.getExpiryDateTime().before(new Date())) {
	respType = ResponseMessageTemplateType.ResponseReceived; // received after deadline
} else if (null == curRespOpt) {
	respType = ResponseMessageTemplateType.NewResponse; // new response
} else if (!newRespOpt.getNameInEmail().equalsIgnoreCase(curRespOpt.getNameInEmail())) {
	respType = ResponseMessageTemplateType.ResponseChanged; // change response
} else if (newRespOpt.getNameInEmail().equalsIgnoreCase(curRespOpt.getNameInEmail())) {
	respType = ResponseMessageTemplateType.ResponseDuplicated; // duplicated response
}
 
// one BroadcastResponseOption has a list of ResponseMessageTemplate (NewResponse, ResponseChanged,...)
List<ResponseMessageTemplate> lstRespMsgTempl = bRespOpt.getResponseOption().getResponseMessageTemplates();
for (ResponseMessageTemplate respMsgTempl : lstRespMsgTempl) {
	if (respType == respMsgTempl.getType()) {
		// get email to send
		String emailSubject = respMsgTempl.getMessageTemplate().getEmailSubject();
		String emailContent = respMsgTempl.getMessageTemplate().getEmailContent();
 
		// send email
		boolean sendingResult = broadcastWorker.sendEmail(emailMessage.getReceiverEmail(), emailSubject, emailContent);
 
		// action after responding
		ActionAfterResponding action = respMsgTempl.getActionAfterResponding();
		if (null != action) {
			// Custom page
			if (ActionAfterRespondingType.Page == action.getType()) {
				String displayContent = action.getContent();
			} else if (ActionAfterRespondingType.Link == action.getType())  { // redirect to link
				String redirectLink = action.getContent();
			}
		}
	}
}