Run a Java Client with OAuth Bearer Token Login

Run a Java client that uses EMP Connector to subscribe to the channel with OAuth authentication.

Prerequisites

Obtain an OAuth bearer access token for your Salesforce user. You supply this access token in the connector example.

See Set Up Authentication with OAuth 2.0. Also see Authenticate Apps with OAuth in Salesforce Help and Understanding Authentication in the REST API Developer Guide.

Let’s run an example that uses OAuth bearer token login.

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

In the /src/main/java/com/salesforce/emp/connector/example folder, open the BearerTokenExample.java Java source file.

1/*
2 * Copyright (c) 2016, salesforce.com, inc. All rights reserved. Licensed under the BSD 3-Clause license. For full
3 * license text, see LICENSE.TXT file in the repo root or https://opensource.org/licenses/BSD-3-Clause
4 */
5package com.salesforce.emp.connector.example;
6
7import java.net.MalformedURLException;
8import java.net.URL;
9import java.util.Map;
10import java.util.concurrent.TimeUnit;
11import java.util.function.Consumer;
12
13import com.salesforce.emp.connector.BayeuxParameters;
14import com.salesforce.emp.connector.EmpConnector;
15import com.salesforce.emp.connector.TopicSubscription;
16import org.cometd.bayeux.Channel;
17
18/**
19 * An example of using the EMP connector using bearer tokens
20 */
21public class BearerTokenExample {
22    public static void main(String[] argv) throws Exception {
23        if (argv.length < 2 || argv.length > 4) {
24            System.err.println("Usage: BearerTokenExample url token topic [replayFrom]");
25            System.exit(1);
26        }
27        long replayFrom = EmpConnector.REPLAY_FROM_EARLIEST;
28        if (argv.length == 4) {
29            replayFrom = Long.parseLong(argv[3]);
30        }
31
32        BayeuxParameters params = new BayeuxParameters() {
33
34            @Override
35            public String bearerToken() {
36                return argv[1];
37            }
38
39            @Override
40            public URL host() {
41                try {
42                    return new URL(argv[0]);
43                } catch (MalformedURLException e) {
44                    throw new IllegalArgumentException(String.format(
45                        "Unable to create url: %s", argv[0]), e);
46                }
47            }
48        };
49
50        Consumer<Map<String, Object>> consumer = event -> System.out.println(
51            String.format("Received:\n%s", event));
52        EmpConnector connector = new EmpConnector(params);
53
54        connector.addListener(Channel.META_CONNECT, new LoggingListener(true, true))
55        .addListener(Channel.META_DISCONNECT, new LoggingListener(true, true))
56        .addListener(Channel.META_HANDSHAKE, new LoggingListener(true, true));
57
58        connector.start().get(5, TimeUnit.SECONDS);
59
60        TopicSubscription subscription = connector.subscribe(
61            argv[2], replayFrom, consumer).get(5, TimeUnit.SECONDS);
62
63        System.out.println(String.format("Subscribed: %s", subscription));
64    }
65}

Run the BearerTokenExample 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, to receive different events, you can include a replay ID as the last argument. 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 past 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}}

In the next step, you learn how to generate notifications using REST.

Streaming API Developer Guide

Run a Java Client with OAuth Bearer Token Login