Helicon Java Sample App

This repository contains the files required to run the Helicon Java Quickstart.

Helicon is a simple, scalable, robust, code-free and generic platform to enable and productise the next generation of "online modified", real-time event stream ML/AI models.

Set up the project

Run mvn clean install to install the project and resolve the dependencies.

Sample App

Publish

This code is available at src/main/java/io/radicalbit/helicon/publish/HeliconPublishApp.java. This example will publish as payload a json object like:

{
"temperature": 26,
"timestamp": 1632143723
}

to a specific stream

private static String host = "<helicon-host>";
private static int port = 443;
private static String clientId = "<client-id>";
private static String clientSecret = "<client-secret>";
private static String tenant = "<tenant-name>";
private static String streamName = "<stream-name>";

public static void main(String[] args) {
    HeliconPublishClient heliconClient = new HeliconPublishClient(host, port, clientId, clientSecret, tenant);

    String payload = "{\"temperature\": 26, \"timestamp\": " + System.currentTimeMillis() + "}";
    heliconClient.write(streamName, payload);
}

Subscribe

Same for subscription, the code is available at src/main/java/io/radicalbit/helicon/subscribe/HeliconSubscribeApp.java, and it is going to print the message defined above.

private static String host = "<helicon-host>";
private static int port = 443;
private static String clientId = "<client-id>";
private static String clientSecret = "<client-secret>";
private static String tenant = "<tenant-name>";
private static String streamName = "<stream-name>";

public static void main(String[] args) {
        HeliconSubscribeClient heliconClient = new HeliconSubscribeClient(host, port, clientId, clientSecret, tenant);

        heliconClient.subscribe(streamName, System.out::println);
}

To be able to read the data you are writing with the publishing client you need to subscribe to the same stream. The message received will be parsed as a GRPC response object before being processed from the response' callback consumer, println in this specific case. You can decide to handle messages in a more specific way, depending on the message you are expecting to read:

• you can use subscribeBinary(String streamName, Consumer<byte[]> callback) to parse the message response as an array of byte.
• you can use subscribeString(String streamName, Consumer<String> callback) to parse the message response as a UTF-8 string.
• you can use subscribeJson(String streamName, Consumer<JSONObject> callback to parse the message response as a JSONObject from JSON-java.

How to Run the app

Running the HeliconSubscribeApp class with your IDE or from a terminal including the classpath of the downloaded jars (java -classpath /path/to/jars src/main/java/io/radicalbit/helicon/publish/HeliconPublishApp), you will start to receive messages as soon as they are written on the stream.

To publish 1 message you can run the HeliconPublishApp class in the same way you have done before for HeliconSubscribeApp, or, for multiple messages, you can wrap it in a loop.

You should see printed the response on the terminal.

Change the API version

The main branch is always updated with the latest version of Helicon API.

If you need to use an old version of the Helicon's API, you can switch between the project version using git checkout tag_version.

You can refer to Helicon documentation for looking more in the depth over the version's features.

Support

We're always happy to help with any other questions you might have! Send us an email.