sdk-java/docs/index.md

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Java SDK for CloudEvents

A Java API for the CloudEvents specification

1. Supported Specification Features
2. Modules
3. Get Started
4. Use an event format
5. Use a protocol binding

Supported Specification Features

Supported features of the specification:

	v0.3	v1.0
CloudEvents Core	✔️	✔️
AMQP Protocol Binding	❌	❌
AVRO Event Format	❌	❌
HTTP Protocol Binding	✔️	✔️
- Vert.x	✔️	✔️
- Jakarta Restful WS	✔️	✔️
JSON Event Format	✔️	✔️
- Jackson	✔️	✔️
Kafka Protocol Binding	✔️	✔️
MQTT Protocol Binding	❌	❌
NATS Protocol Binding	❌	❌
Web hook	❌	❌

Modules

The CloudEvents SDK for Java is composed by several modules, each one providing a different feature from the different sub specs of CloudEvents specification:

• cloudevents-api Module providing the CloudEvent and other base interfaces
• cloudevents-core Module providing CloudEvent implementation, CloudEventBuilder to create CloudEvents programmatically, EventFormat to implement Event Formats, Message/MessageVisitor to implement Protocol bindings
• cloudevents-json-jackson Implementation of JSON Event format with Jackson
• cloudevents-http-vertx Implementation of HTTP Protocol Binding with Vert.x Core
• cloudevents-http-restful-ws Implementation of HTTP Protocol Binding for Jakarta Restful WS
• cloudevents-kafka Implementation of Kafka Protocol Binding

You can look at the latest published artifacts on Maven Central.

Get Started

You can start creating events using the CloudEventBuilder:

import io.cloudevents.CloudEvent;
import io.cloudevents.core.builder.CloudEventBuilder;
import java.net.URI;

final CloudEvent event = CloudEventBuilder.v1()
    .withId("000")
    .withType("example.demo")
    .withSource(URI.create("http://example.com"))
    .withData("application/json", "{}".getBytes())
    .build();

Look at cloudevents-core README for more information.

Use an event format

Event formats implementations are auto-discovered through an SPI. You can use them accessing through EventFormatProvider. For example, given you have in your classpath the cloudevents-json-jackson module, you can serialize/deserialize an event to/from JSON using:

import io.cloudevents.core.format.EventFormatProvider;
import io.cloudevents.jackson.JsonFormat;

EventFormat format = EventFormatProvider
  .getInstance()
  .resolveFormat(JsonFormat.CONTENT_TYPE);

// Serialize event
byte[] serialized = format.serialize(event);

// Deserialize event
CloudEvent event = format.deserialize(bytes);

Use a protocol binding

Each protocol binding has its own APIs, depending on the library/framework it's integrating with. Check out the documentation of the protocol binding modules:

• cloudevents-http-vertx
• cloudevents-http-restful-ws
• cloudevents-kafka