A simplified connector example to the Enterprise Messaging Platform.
This example connector provides support for SSL, HTTP proxies and supports both the long polling and websocket streaming transports. Easy subscription management and full support for event replay is provided. The connector is a thin wrapper around the underlying CometD library.
The EMP-Connector sample is deprecated and will be archived in the future. The EMP-Connector code is an example only and isn't intended for production environments. It hasn't been rigorously tested nor performance tested for throughput and scale.
Are you looking for a code sample for subscribing to platform events and change events? Check out the Java Quick Start for Pub/Sub API in the Pub/Sub API Guide.
Several example classes are provided to subscribe to a channel. All classes contain a main function that starts the tool. All examples authenticate to Salesforce and subscribe to a channel. Some examples use a different authentication mechanism or provide verbose logging.
All classes process events asynchronously in a separate thread. This ensures that EMP Connector continues to perform /meta/connect requests and keeps the session alive on the server.
Currently, one thread is used for event processing and events are processed in the order they're received. You can increase the number of threads for parallel processing. However, doing so may cause events to not be processed in the order received.
The LoginExample.java class is the default class that EMP Connector executes. This class authenticates to your production Salesforce org using your Salesforce username and password.
The DevLoginExample class enables you to pass in a custom login URL, such as a sandbox instance (https://test.salesforce.com). Also, DevLoginExample logs to the console the Bayeux connection messages received on the /meta channels, such as /meta/handshake and /meta/connect.
The BearerExample.java class uses the OAuth bearer token authentication and accepts an access token.
After cloning the project, build EMP Connector using Maven:
$ mvn clean package
The build generates the jar file in the target subfolder.
To run EMP Connector using the LoginExample class with username and password authentication, use this command.
$ java -jar target/emp-connector-0.0.1-SNAPSHOT-phat.jar <username> <password> <channel> [optional_replay_id]
To run EMP Connector using the DevLoginExample class with username and password authentication, use this command.
$ java -classpath target/emp-connector-0.0.1-SNAPSHOT-phat.jar com.salesforce.emp.connector.example.DevLoginExample <login_URL> <username> <password> <channel> [optional_replay_id]
To run EMP Connector using an OAuth access token, use this command.
$ java -classpath target/emp-connector-0.0.1-SNAPSHOT-phat.jar com.salesforce.emp.connector.example.BearerTokenExample <instance_URL> <token> <channel> [optional_replay_id]
The last parameter is the replay ID, which is the position in the stream from which you want to receive event messages. This parameter is optional. If not specified, EMP Connector fetches events starting from the tip, the newly received event messages (-1 option). To receive stored event messages that are within the retention window, specify -2. Use -2 sparingly. If a large volume of event messages is stored, retrieving all event messages can slow performance. For more information, see Message Durability.