The Talon Manual

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FieldTypeDescription
Channel Identification
MessageChannelNameString

The name of the channel.

This is used by the receiver to lookup the channel on which the message should be dispatched to the application.

MessageChannelIdshort

The id of the channel.

This is used by the receiver to lookup the channel on which the message should be dispatched to the application. Using a channel id allows for more efficient lookup of the channel, but care must be taken that the specified channel id matches that configured for receivers of the message will be flagged as an unhandled message.

Message Encoding
Message encoding fields allows a receiving application to lookup a message factory and use it to deserialize or wrap a message.
MessageViewFactoryshort

The id of the factory that is used to deserialize the message.

This is used by the receiver to lookup the factory that is used to deserialize (or wrap) the received message payload.

The message view factory id can be determined by calling MessageView.getVfid()on a message. For ADM modeled messages, this will be the negative of the factory id defined in the model (user factory types are negative at runtime to distinguish between user and platform factory types).

MessageViewTypeshort

The id of the type (unique to its factory) used to deserialize the message.

The message view type can be determined by calling MessageView.getType() on a message. For ADM modeled messages, this will be the id of the message defined in the ADM model.

MessageEncodingTypebyte 

The encoding type of the message.

The encoding type is used by the factory to differentiate between possible encodings supported by the message, but may also be used by wire sniffers as a hint to decoding the message. Valid values are:

  • 3: Protobuf The encoded payload is a series of google protobuf bytes
  • 4: Xbuf The encoded payload is a series of google protobuf bytes which may use extensions employed by talon's protobuf implementat.
  • 5: Json The encoded payload is a utf-8 encoded string with json content.
  • 1: Custom The encoded payload is opaque bytes.
Message Sequencing
Message sequencing fields allow for the receiving application to filter duplicate and out of order messages. For a given sender id and flow, an AepEngine will filter out received messages that don't have a monotonically increasing sequence number
MessageSenderintA globally unique id that identifies the sender of a message.

By default an AepEngine uses the hashcode of the engine name as the sender id.  
MessageSnolong

A monotonically increasing sequence number.  

  • A sequence number of <=0 indicates that the message is not sequenced. Receivers should not perform duplicate checking on it.
  • A sequence number of 1 indicates that the start (or restart of a stream). A receiver that receives sequence numbers 1,2,3,1,2,3 should not consider the 4th message a duplicate.
  • Otherwise, receivers should consider a sequence number not greater than the previous sequence number as a duplicate.  
MessageFlowintIndicates the flow to which the message belongs. Flows allow for partitioning of message traffic in conjunction with application state and allow intra application state partitioning.

(warning) Usage of flows is not currently supported for end users. External senders should always set the flow to 0.

SMA MessageMetadata Class

SMA provides a helper class, com.neeve.sma.MessageMetadata, that can be used by applications to assist in working with message metadata. This helper class provides the ability to serialize data into a binary format and also serves a view around this metadata. Binding such as the Solace binding encode metadata in binary serialized format for optimized transmission, while other lower performance bindings encode metadata as property values in the message header. 

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