com.azure.messaging.eventhubs

Class EventHubProducerAsyncClient

java.lang.Object

com.azure.messaging.eventhubs.EventHubProducerAsyncClient

All Implemented Interfaces:

Closeable, AutoCloseable

public class EventHubProducerAsyncClient
extends Object
implements Closeable

An asynchronous producer responsible for transmitting EventData to a specific Event Hub, grouped together in batches. Depending on the options specified when creating an EventDataBatch, the events may be automatically routed to an available partition or specific to a partition.

Allowing automatic routing of partitions is recommended when:

• The sending of events needs to be highly available.
• The event data should be evenly distributed among all available partitions.

If no partition id is specified, the following rules are used for automatically selecting one:

1. Distribute the events equally amongst all available partitions using a round-robin approach.
2. If a partition becomes unavailable, the Event Hubs service will automatically detect it and forward the message to another available partition.

Create a producer and publish events to any partition

// The required parameter is a way to authenticate with Event Hubs using credentials.
// The connectionString provides a way to authenticate with Event Hub.
EventHubProducerClient producer = new EventHubClientBuilder()
    .connectionString(
        "Endpoint={fully-qualified-namespace};SharedAccessKeyName={policy-name};SharedAccessKey={key}",
        "event-hub-name")
    .buildProducerClient();
List<EventData> events = Arrays.asList(new EventData("test-event-1"), new EventData("test-event-2"));

// Creating a batch without options set, will allow for automatic routing of events to any partition.
EventDataBatch batch = producer.createBatch();
for (EventData event : events) {
    if (batch.tryAdd(event)) {
        continue;
    }

    producer.send(batch);
    batch = producer.createBatch();
    if (!batch.tryAdd(event)) {
        throw new IllegalArgumentException("Event is too large for an empty batch.");
    }
}

Publish events to partition "foo"

// Creating a batch with partitionId set will route all events in that batch to partition `foo`.
CreateBatchOptions options = new CreateBatchOptions().setPartitionId("foo");
producer.createBatch(options).flatMap(batch -> {
    batch.tryAdd(new EventData("test-event-1"));
    batch.tryAdd(new EventData("test-event-2"));
    return producer.send(batch);
}).subscribe(unused -> {
},
    error -> System.err.println("Error occurred while sending batch:" + error),
    () -> System.out.println("Send complete."));

Publish events to the same partition, grouped together using partition key

// Creating a batch with partitionKey set will tell the service to hash the partitionKey and decide which
// partition to send the events to. Events with the same partitionKey are always routed to the same partition.
CreateBatchOptions options = new CreateBatchOptions().setPartitionKey("bread");
producer.createBatch(options).flatMap(batch -> {
    batch.tryAdd(new EventData("sourdough"));
    batch.tryAdd(new EventData("rye"));
    return producer.send(batch);
}).subscribe(unused -> {
},
    error -> System.err.println("Error occurred while sending batch:" + error),
    () -> System.out.println("Send complete."));

Publish events using a size-limited EventDataBatch

final Flux<EventData> telemetryEvents = Flux.just(firstEvent, secondEvent);

// Setting `setMaximumSizeInBytes` when creating a batch, limits the size of that batch.
// In this case, all the batches created with these options are limited to 256 bytes.
final CreateBatchOptions options = new CreateBatchOptions()
    .setMaximumSizeInBytes(256);
final AtomicReference<EventDataBatch> currentBatch = new AtomicReference<>(
    producer.createBatch(options).block());

// The sample Flux contains two events, but it could be an infinite stream of telemetry events.
telemetryEvents.flatMap(event -> {
    final EventDataBatch batch = currentBatch.get();
    if (batch.tryAdd(event)) {
        return Mono.empty();
    }

    return Mono.when(
        producer.send(batch),
        producer.createBatch(options).map(newBatch -> {
            currentBatch.set(newBatch);

            // Add the event that did not fit in the previous batch.
            if (!newBatch.tryAdd(event)) {
                throw Exceptions.propagate(new IllegalArgumentException(
                    "Event was too large to fit in an empty batch. Max size: " + newBatch.getMaxSizeInBytes()));
            }

            return newBatch;
        }));
}).then()
    .doFinally(signal -> {
        final EventDataBatch batch = currentBatch.getAndSet(null);
        if (batch != null && batch.getCount() > 0) {
            producer.send(batch).block();
        }
    });

See Also:

EventHubClientBuilder.buildAsyncProducerClient(), To synchronously generate events to an Event Hub, see EventHubProducerClient.

Method Summary

Modifier and Type	Method and Description
void	close() Disposes of the EventHubProducerAsyncClient.
Mono<EventDataBatch>	createBatch() Creates an EventDataBatch that can fit as many events as the transport allows.
Mono<EventDataBatch>	createBatch(CreateBatchOptions options) Creates an EventDataBatch configured with the options specified.
String	getEventHubName() Gets the Event Hub name this client interacts with.
Mono<EventHubProperties>	getEventHubProperties() Retrieves information about an Event Hub, including the number of partitions present and their identifiers.
String	getFullyQualifiedNamespace() Gets the fully qualified Event Hubs namespace that the connection is associated with.
Flux<String>	getPartitionIds() Retrieves the identifiers for the partitions of an Event Hub.
Mono<PartitionProperties>	getPartitionProperties(String partitionId) Retrieves information about a specific partition for an Event Hub, including elements that describe the available events in the partition event stream.
Mono<Void>	send(EventDataBatch batch) Sends the batch to the associated Event Hub.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

getFullyQualifiedNamespace

public String getFullyQualifiedNamespace()

Gets the fully qualified Event Hubs namespace that the connection is associated with. This is likely similar to {yournamespace}.servicebus.windows.net.

Returns:

The fully qualified Event Hubs namespace that the connection is associated with.

getEventHubName

public String getEventHubName()

Gets the Event Hub name this client interacts with.

Returns:

The Event Hub name this client interacts with.

getEventHubProperties

public Mono<EventHubProperties> getEventHubProperties()

Retrieves information about an Event Hub, including the number of partitions present and their identifiers.

Returns:

The set of information for the Event Hub that this client is associated with.

getPartitionIds

public Flux<String> getPartitionIds()

Retrieves the identifiers for the partitions of an Event Hub.

Returns:

A Flux of identifiers for the partitions of an Event Hub.

getPartitionProperties

public Mono<PartitionProperties> getPartitionProperties(String partitionId)

Retrieves information about a specific partition for an Event Hub, including elements that describe the available events in the partition event stream.

Parameters:

partitionId - The unique identifier of a partition associated with the Event Hub.

Returns:

The set of information for the requested partition under the Event Hub this client is associated with.

Throws:

NullPointerException - if partitionId is null.

createBatch

public Mono<EventDataBatch> createBatch()

Creates an EventDataBatch that can fit as many events as the transport allows.

Returns:

A new EventDataBatch that can fit as many events as the transport allows.

createBatch

public Mono<EventDataBatch> createBatch(CreateBatchOptions options)

Creates an EventDataBatch configured with the options specified.

Parameters:

options - A set of options used to configure the EventDataBatch.

Returns:

A new EventDataBatch that can fit as many events as the transport allows.

Throws:

NullPointerException - if options is null.

send

public Mono<Void> send(EventDataBatch batch)

Sends the batch to the associated Event Hub.

Parameters:

batch - The batch to send to the service.

Returns:

A Mono that completes when the batch is pushed to the service.

Throws:

NullPointerException - if batch is null.

See Also:

EventHubProducerAsyncClient.createBatch(), EventHubProducerAsyncClient.createBatch(CreateBatchOptions)

close

public void close()

Disposes of the EventHubProducerAsyncClient. If the client had a dedicated connection, the underlying connection is also closed.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable