Run a Java Client with Username and Password Login

Run a Java client that uses EMP Connector to subscribe to the channel with username and password authentication.

Get the EMP Connector project from GitHub. See Download and Build the Project.

Under the /src/main/java/ folder, open the LoginExample.java Java source file from the example package folder.

1/* 
2 * Copyright (c) 2016, salesforce.com, inc.
3 * All rights reserved.
4 * Licensed under the BSD 3-Clause license. 
5 * For full license text, see LICENSE.TXT file in the repo root  or https://opensource.org/licenses/BSD-3-Clause
6 */
7package com.salesforce.emp.connector.example;
8
9import static com.salesforce.emp.connector.LoginHelper.login;
10
11import java.util.Map;
12import java.util.concurrent.TimeUnit;
13import java.util.function.Consumer;
14
15import com.salesforce.emp.connector.BayeuxParameters;
16import com.salesforce.emp.connector.EmpConnector;
17import com.salesforce.emp.connector.TopicSubscription;
18
19/**
20 * An example of using the EMP connector using login credentials
21 *
22 * @author hal.hildebrand
23 */
24public class LoginExample {
25    public static void main(String[] argv) throws Exception {
26        if (argv.length < 3 || argv.length > 4) {
27            System.err.println("Usage: LoginExample username password topic [replayFrom]");
28            System.exit(1);
29        }
30        long replayFrom = EmpConnector.REPLAY_FROM_EARLIEST;
31        if (argv.length == 4) {
32            replayFrom = Long.parseLong(argv[3]);
33        }
34
35        BayeuxParameters params;
36        try {
37            params = login(argv[0], argv[1]);
38        } catch (Exception e) {
39            e.printStackTrace(System.err);
40            System.exit(1);
41            throw e;
42        } 
43
44        Consumer<Map<String, Object>> consumer = event -> System.out.println(
45                String.format("Received:\n%s", event));
46        EmpConnector connector = new EmpConnector(params);
47
48        connector.start().get(5, TimeUnit.SECONDS);
49
50        TopicSubscription subscription = connector.subscribe(argv[2], 
51            replayFrom, consumer).get(5, TimeUnit.SECONDS);
52
53        System.out.println(String.format("Subscribed: %s", subscription));
54    }
55}

Run the LoginExample class and provide the following argument values.

Argument	Value
`username`	Username of the logged-in user.
`password`	Password for the `username` (or logged-in user).
`topic`	`/u/notifications/ExampleUserChannel`

The sample fetches the earliest saved events within the past 24 hours. Optionally, you can supply a replay ID as the last argument to receive different events. Valid values are:

-1—Get all new events sent after subscription.
-2—Get all new events sent after subscription and all past events within the last 24 hours.
Specific number—Get all events that occurred after the event with the specified replay ID.

When you run this client app and generate notifications using the REST resource, the output will look something like:

1Subscribed: Subscription [/u/notifications/ExampleUserChannel:-2]
2Received:
3{payload=Broadcast message to all subscribers, event={createdDate=2016-12-13T00:57:36.020Z, replayId=1}}
4Received:
5{payload=Another message, event={createdDate=2016-12-13T00:58:16.591Z, replayId=2}}

Generally, do not handle usernames and passwords of others when running code in production. In a production environment, delegate the login to OAuth. The next step connects to Streaming API with OAuth.

Force.com Streaming API Developer Guide

Run a Java Client with Username and Password Login