Package org.axonframework.messaging

Interface Message<T>

Type Parameters:
T - the type of payload contained in this Message
All Superinterfaces:
Serializable
All Known Subinterfaces:
CommandMessage<T>, CommandResultMessage<R>, DeadlineMessage<T>, DomainEventMessage<T>, EventMessage<T>, QueryMessage<T,R>, QueryResponseMessage<T>, ResetContext<T>, ResultMessage<R>, StreamingQueryMessage<Q,R>, SubscriptionQueryMessage<Q,I,U>, SubscriptionQueryUpdateMessage<U>, TrackedEventMessage<T>
All Known Implementing Classes:
AbstractMessage, ConvertingResponseMessage, GenericCommandMessage, GenericCommandResultMessage, GenericDeadlineMessage, GenericDomainEventMessage, GenericEventMessage, GenericMessage, GenericQueryMessage, GenericQueryResponseMessage, GenericResetContext, GenericResultMessage, GenericStreamingQueryMessage, GenericSubscriptionQueryMessage, GenericSubscriptionQueryUpdateMessage, GenericTrackedDomainEventMessage, GenericTrackedEventMessage, GrpcBackedCommandMessage, GrpcBackedQueryMessage, GrpcBackedResponseMessage, GrpcBackedSubscriptionQueryMessage, MessageDecorator, SerializedMessage
public interface Message<T> extends Serializable
Representation of a Message, containing a Payload and MetaData. Typical examples of Messages are Commands, Events and Queries.

Instead of implementing Message directly, consider implementing CommandMessage, EventMessage or QueryMessage instead.

Since:
2.0
Author:
Allard Buijze
See Also:

  • Method Details

    • getIdentifier

      String getIdentifier()
      Returns the identifier of this message. Two messages with the same identifiers should be interpreted as different representations of the same conceptual message. In such case, the meta-data may be different for both representations. The payload may be identical.
      Returns:
      the unique identifier of this message

    • getMetaData

      MetaData getMetaData()
      Returns the meta data for this message. This meta data is a collection of key-value pairs, where the key is a String, and the value is a serializable object.
      Returns:
      the meta data for this message

    • getPayload

      T getPayload()
      Returns the payload of this message. The payload is the application-specific information.
      Returns:
      the payload of this message

    • getPayloadType

      Class<T> getPayloadType()
      Returns the type of the payload.

      Is semantically equal to getPayload().getClass(), but allows implementations to optimize by using lazy loading or deserialization.

      Returns:
      the type of payload.

    • withMetaData

      Message<T> withMetaData(@Nonnull Map<String,?> metaData)
      Returns a copy of this Message with the given metaData. The payload remains unchanged.

      While the implementation returned may be different than the implementation of this, implementations must take special care in returning the same type of Message (e.g. EventMessage, DomainEventMessage) to prevent errors further downstream.

      Parameters:
      metaData - The new MetaData for the Message
      Returns:
      a copy of this message with the given MetaData

    • andMetaData

      Message<T> andMetaData(@Nonnull Map<String,?> metaData)
      Returns a copy of this Message with it MetaData merged with the given metaData. The payload remains unchanged.
      Parameters:
      metaData - The MetaData to merge with
      Returns:
      a copy of this message with the given MetaData

    • serializePayload

      default <R> SerializedObject<R> serializePayload(Serializer serializer, Class<R> expectedRepresentation)
      Serialize the payload of this message to the expectedRepresentation using given serializer. This method should return the same SerializedObject instance when invoked multiple times using the same serializer.
      Type Parameters:
      R - The type of the serialized data
      Parameters:
      serializer - The serializer to serialize payload with
      expectedRepresentation - The type of data to serialize to
      Returns:
      a SerializedObject containing the serialized representation of the message's payload

    • serializeMetaData

      default <R> SerializedObject<R> serializeMetaData(Serializer serializer, Class<R> expectedRepresentation)
      Serialize the meta data of this message to the expectedRepresentation using given serializer. This method should return the same SerializedObject instance when invoked multiple times using the same serializer.
      Type Parameters:
      R - The type of the serialized data
      Parameters:
      serializer - The serializer to serialize meta data with
      expectedRepresentation - The type of data to serialize to
      Returns:
      a SerializedObject containing the serialized representation of the message's meta data