public static void main(String... args) throws Exception {

// TODO(developer): Replace these variables before running the sample.

String projectId = "your-project-id";

// Use a topic created with a proto schema.

String topicId = "your-topic-id";

publishProtobufMessagesExample(projectId, topicId);

}

public static void publishProtobufMessagesExample(String projectId, String topicId)

throws IOException, ExecutionException, InterruptedException {

Encoding encoding = null;

TopicName topicName = TopicName.of(projectId, topicId);

// Get the topic encoding type.

try (TopicAdminClient topicAdminClient = TopicAdminClient.create()) {

encoding = topicAdminClient.getTopic(topicName).getSchemaSettings().getEncoding();

}

Publisher publisher = null;

// Instantiate a protoc-generated class defined in `us-states.proto`.

State state = State.newBuilder().setName("Alaska").setPostAbbr("AK").build();

block:

try {

publisher = Publisher.newBuilder(topicName).build();

PubsubMessage.Builder message = PubsubMessage.newBuilder();

// Prepare an appropriately formatted message based on topic encoding.

switch (encoding) {

case BINARY:

message.setData(state.toByteString());

System.out.println("Publishing a BINARY-formatted message:\n" + message);

break;

case JSON:

String jsonString = JsonFormat.printer().omittingInsignificantWhitespace().print(state);

message.setData(ByteString.copyFromUtf8(jsonString));

System.out.println("Publishing a JSON-formatted message:\n" + message);

break;

default:

break block;

}

// Publish the message.

ApiFuture<String> future = publisher.publish(message.build());

System.out.println("Published message ID: " + future.get());

} finally {

if (publisher != null) {

publisher.shutdown();

publisher.awaitTermination(1, TimeUnit.MINUTES);

}

}

}