EventData Class

Package:

com.azure.messaging.eventhubs

Maven Artifact:

com.azure:azure-messaging-eventhubs:5.18.3

• java.lang.Object
• • com.azure.core.models.MessageContent
  • • com.azure.messaging.eventhubs.EventData

public class EventData
extends MessageContent

The data structure encapsulating the event being sent-to and received-from Event Hubs. Each Event Hub partition can be visualized as a stream of EventData. This class is not thread-safe.

Constructor Summary

Constructor	Description
EventData()	Creates an event with an empty body.
EventData(byte[] body)	Creates an event containing the body.
EventData(BinaryData body)	Creates an event with the provided BinaryData as payload.
EventData(String body)	Creates an event by encoding the body using UTF-8 charset.
EventData(ByteBuffer body)	Creates an event containing the body.

Method Summary

Modifier and Type	Method and Description
EventData	addContext(String key, Object value) Adds a new key value pair to the existing context on Event Data.
boolean	equals(Object o) True if the object is an EventData and the binary contents of getBody() are equal.
byte[]	getBody() Gets the actual payload/data wrapped by EventData.
BinaryData	getBodyAsBinaryData() Returns the BinaryData payload associated with this event.
String	getBodyAsString() Returns event data as UTF-8 decoded string.
String	getContentType() Gets the MIME type describing the data contained in the getBody(), intended to allow consumers to make informed decisions for inspecting and processing the event.
String	getCorrelationId() Gets an application-defined value that represents the context to use for correlation across one or more operations.
Instant	getEnqueuedTime() Gets the instant, in UTC, of when the event was enqueued in the Event Hub partition.
String	getMessageId() Gets an application-defined value that uniquely identifies the event.
Long	getOffset() Gets the offset of the event when it was received from the associated Event Hub partition.
String	getPartitionKey() Gets the partition hashing key if it was set when originally publishing the event.
Map<String,Object>	getProperties() Gets the set of free-form event properties which may be used for passing metadata associated with the event with the event body during Event Hubs operations.
AmqpAnnotatedMessage	getRawAmqpMessage() Gets the underlying AMQP message.
Long	getSequenceNumber() Gets the sequence number assigned to the event when it was enqueued in the associated Event Hub partition.
Map<String,Object>	getSystemProperties() Properties that are populated by Event Hubs service.
int	hashCode() Gets a hash of the binary contents in getBody().
EventData	setBodyAsBinaryData(BinaryData binaryData) Sets a new binary body and corresponding AmqpAnnotatedMessage on the event.
EventData	setContentType(String contentType) Sets the MIME type describing the data contained in the getBody(), intended to allow consumers to make informed decisions for inspecting and processing the event.
EventData	setCorrelationId(String correlationId) Sets an application-defined value that represents the context to use for correlation across one or more operations.
EventData	setMessageId(String messageId) Sets an application-defined value that uniquely identifies the event.

Methods inherited from MessageContent

getBodyAsBinaryData getContentType setBodyAsBinaryData setContentType

Methods inherited from java.lang.Object

clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Constructor Details

EventData

public EventData()

Creates an event with an empty body.

EventData

public EventData(byte[] body)

Creates an event containing the body.

Parameters:

body - The data to set for this event.

EventData

public EventData(BinaryData body)

Creates an event with the provided BinaryData as payload.

Parameters:

body - The BinaryData payload for this event.

EventData

public EventData(String body)

Creates an event by encoding the body using UTF-8 charset.

Parameters:

body - The string that will be UTF-8 encoded to create an event.

EventData

public EventData(ByteBuffer body)

Creates an event containing the body.

Parameters:

body - The data to set for this event.

Method Details

addContext

public EventData addContext(String key, Object value)

Adds a new key value pair to the existing context on Event Data.

Parameters:

key - The key for this context object

value - The value for this context object.

Returns:

The updated EventData.

equals

public boolean equals(Object o)

True if the object is an EventData and the binary contents of getBody() are equal.

Overrides:

EventData.equals(Object o)

Parameters:

o

getBody

public byte[] getBody()

Gets the actual payload/data wrapped by EventData.

If the means for deserializing the raw data is not apparent to consumers, a common technique is to make use of getProperties() when creating the event, to associate serialization hints as an aid to consumers who wish to deserialize the binary data.

Returns:

A byte array representing the data.

getBodyAsBinaryData

public BinaryData getBodyAsBinaryData()

Returns the BinaryData payload associated with this event.

Overrides:

EventData.getBodyAsBinaryData()

Returns:

the BinaryData payload associated with this event.

getBodyAsString

public String getBodyAsString()

Returns event data as UTF-8 decoded string.

Returns:

UTF-8 decoded string representation of the event data.

getContentType

public String getContentType()

Gets the MIME type describing the data contained in the getBody(), intended to allow consumers to make informed decisions for inspecting and processing the event.

Overrides:

EventData.getContentType()

Returns:

The content type.

getCorrelationId

public String getCorrelationId()

Gets an application-defined value that represents the context to use for correlation across one or more operations. The identifier is a free-form value and may reflect a unique identity or a shared data element with significance to the application.

Returns:

The correlation id. null if there is none set.

getEnqueuedTime

public Instant getEnqueuedTime()

Gets the instant, in UTC, of when the event was enqueued in the Event Hub partition. This is only present on a received EventData.

Returns:

The instant, in UTC, this was enqueued in the Event Hub partition. null if the EventData was not received from Event Hubs service.

getMessageId

public String getMessageId()

Gets an application-defined value that uniquely identifies the event. The identifier is a free-form value and can reflect a GUID or an identifier derived from the application context.

Returns:

The message id. null if there is none set.

getOffset

public Long getOffset()

Gets the offset of the event when it was received from the associated Event Hub partition. This is only present on a received EventData.

Returns:

The offset within the Event Hub partition of the received event. null if the EventData was not received from Event Hubs service.

getPartitionKey

public String getPartitionKey()

Gets the partition hashing key if it was set when originally publishing the event. If it exists, this value was used to compute a hash to select a partition to send the message to. This is only present on a received EventData.

Returns:

A partition key for this Event Data. null if the EventData was not received from Event Hubs service or there was no partition key set when the event was sent to the Event Hub.

getProperties

public Map getProperties()

Gets the set of free-form event properties which may be used for passing metadata associated with the event with the event body during Event Hubs operations. A common use-case for properties() is to associate serialization hints for the getBody() as an aid to consumers who wish to deserialize the binary data.

Adding serialization hint using getProperties()

In the sample, the type of telemetry is indicated by adding an application property with key "eventType".

TelemetryEvent telemetry = new TelemetryEvent("temperature", "37");
 byte[] serializedTelemetryData = telemetry.toString().getBytes(UTF_8);

 EventData eventData = new EventData(serializedTelemetryData);
 eventData.getProperties().put("eventType", TelemetryEvent.class.getName());

The following types are supported:

• Character
• Date
• Double
• Float
• Integer
• Long
• Short
• String

Returns:

Application properties associated with this EventData. For received EventData, the map is a read-only view.

getRawAmqpMessage

public AmqpAnnotatedMessage getRawAmqpMessage()

Gets the underlying AMQP message.

Returns:

The underlying AMQP message.

getSequenceNumber

public Long getSequenceNumber()

Gets the sequence number assigned to the event when it was enqueued in the associated Event Hub partition. This is unique for every message received in the Event Hub partition. This is only present on a received EventData.

Returns:

The sequence number for this event. null if the EventData was not received from Event Hubs service.

getSystemProperties

public Map getSystemProperties()

Properties that are populated by Event Hubs service. As these are populated by the Event Hubs service, they are only present on a received EventData. Provides an abstraction on top of properties exposed by getRawAmqpMessage(). These properties are read-only and can be modified via getRawAmqpMessage().

Returns:

An encapsulation of all system properties appended by EventHubs service into EventData. If the EventData is not received from the Event Hubs service, the values returned are null.

hashCode

public int hashCode()

Gets a hash of the binary contents in getBody().

Overrides:

EventData.hashCode()

setBodyAsBinaryData

public EventData setBodyAsBinaryData(BinaryData binaryData)

Sets a new binary body and corresponding AmqpAnnotatedMessage on the event. Contents from getRawAmqpMessage() are shallow copied to the new underlying message.

Overrides:

EventData.setBodyAsBinaryData(BinaryData binaryData)

Parameters:

binaryData

setContentType

public EventData setContentType(String contentType)

Sets the MIME type describing the data contained in the getBody(), intended to allow consumers to make informed decisions for inspecting and processing the event.

Overrides:

EventData.setContentType(String contentType)

Parameters:

contentType - The content type.

Returns:

The updated EventData.

setCorrelationId

public EventData setCorrelationId(String correlationId)

Sets an application-defined value that represents the context to use for correlation across one or more operations. The identifier is a free-form value and may reflect a unique identity or a shared data element with significance to the application.

Parameters:

correlationId - The correlation id.

Returns:

The updated EventData.

setMessageId

public EventData setMessageId(String messageId)

Sets an application-defined value that uniquely identifies the event. The identifier is a free-form value and can reflect a GUID or an identifier derived from the application context.

Parameters:

messageId - The message id.

Returns:

The updated EventData.