Use websockets or and HTTP Pubsub server with Jetty or Tomcat (Cometd Ajax). Just implement a Bolt that posts to either of these instrumentations. Here is an example of a bolt that connects to an HTTP pubsub server and posts and event as well as the java script that you will need on your JSP.
Publish HTTP Bolt ..
public class PublishTransaction extends BaseRichBolt {
private static final long serialVersionUID = 1L;
private String pubSubUrl = Constants.pubSubUrl;
private String incomingTransactionsChannel = Constants.incomingTransactionsChannel;
private BayeuxClient bayuexClient;
private OutputCollector collector;
public void execute(Tuple tuple) {
EnrichedTransaction transaction = (EnrichedTransaction) tuple.getValueByField("EnrichedTransaction");
Map<String, Object> data = new HashMap<String, Object>();
data.put("transactionId", transaction.getTransactionId());
data.put("transactionTimeStamp", transaction.getTransactionTimeStamp());
bayuexClient.getChannel(incomingTransactionsChannel).publish(data);
collector.emit(tuple, new Values((EnrichedTransaction)transaction));
collector.ack(tuple);
}
public void prepare(Map arg0, TopologyContext arg1, OutputCollector collector) {
this.collector = collector;
HttpClient httpClient = new HttpClient();
try {
httpClient.start();
} catch (Exception e) {
e.printStackTrace();
}
// Prepare the transport
Map<String, Object> options = new HashMap<String, Object>();
ClientTransport transport = new LongPollingTransport(options, httpClient);
// Create the BayeuxClient
bayuexClient = new BayeuxClient(pubSubUrl, transport);
bayuexClient.handshake();
boolean handshaken = bayuexClient.waitFor(3000, BayeuxClient.State.CONNECTED);
if (handshaken)
{
System.out.println("Connected to Cometd Http PubSub Platform");
}
else{
System.out.println("Could not connect to Cometd Http PubSub Platform");
}
}
public void declareOutputFields(OutputFieldsDeclarer declarer) {
declarer.declare(new Fields("EnrichedTransaction"));
}
Then some Javascript on the view (JSP or whatever tech you use on the user side
JavaScript
<script src="//ajax.googleapis.com/ajax/libs/dojo/1.7.8/dojo/dojo.js"></script>
<script>
dojo.require("dojo.io.script");
dojo.require("dojox.cometd");
dojo.require("dojox.cometd.longPollTransport");
var table;
var tableData;
var pubSubUrl = "http://ip:port/cometd";
var alertChannel = "/fraudAlert";
var incomingTransactionsChannel = "/incomingTransactions";
var customerValidationChannel = "/accountStatusUpdate";
dojo.ready(connectAccountStatusUpdateTopic)
function connectAccountStatusUpdateTopic(){
dojox.cometd.init(pubSubUrl);
dojox.cometd.subscribe("/*", function(message){
if(message.channel == customerValidationChannel){
console.log(message)
var fraudulent = message.data.fraudulent;
if(fraudulent=="true"){
document.getElementById("account_container").style.backgroundColor = "#FF0000";
document.getElementById("accountStatus").innerHTML = "Suspended";
}else{
document.getElementById("account_container").style.backgroundColor = "#9CF";
document.getElementById("accountStatus").innerHTML = "Active";
location.href='CustomerOverview?requestType=customerDetails&accountNumber=' + ${accountDetails.accountNumber};
}
}if(message.channel == incomingTransactionsChannel || message.channel == alertChannel){
}
});
}
