Managing Messages in the Solace Java RTO API

The following sections discuss how you can manage messages when you use the Solace Java RTO API.

Getting Message Properties

A client can obtain message properties from a created message before it is published or from a message the API receives from the event broker.

For a complete list of message properties that can be retrieved, see the appropriate API in the Solace Messaging APIs section.

Some message properties, such as expiration, TTL and dead message queue eligibility, are only valid when used with guaranteed messages. See the relevant API reference documentation for more information.

To Get Message Properties

In the Solace Java RTO API, use all MessageHandle.get*() methods. For example:

  • MessageHandle.getApplicationMessageType()

  • MessageHandle.getDeliveryCount()

  • MessageHandle.getSenderId()

For a complete list of methods, see the Solace Java RTO API reference.

Setting Message Properties

A client can set message properties on a created message before it is published or on a message the API receives from the event broker.

For a complete list of message properties that can be set, see the appropriate API in the Solace Messaging APIs section.

Some message properties, such as expiration, TTL and dead message queue eligibility, are only valid when used with guaranteed messages. See the relevant API reference documentation for more information.

To Set Message Properties

In the Solace Java RTO API, use all MessageHandle.set*() methods. For example:

  • MessageHandle.setApplicationMessageType(java.lang.String appMsgType)

  • MessageHandle.setCorrelationId(java.lang.String correlationId)

  • MessageHandle.setSenderId(java.lang.String senderId)

For a complete list of methods, see the Solace Java RTO API reference.

Duplicating Messages

In the Solace Java RTO API, message duplication is not applicable.

Displaying Messages

You can use the message dump utility to display the contents of a message in a human‑readable form. This utility method or function is provided as a programming aid to facilitate the development and testing of messaging applications. You can display the contents of a created message or a received message.

To Display Message Contents

In the Solace Java RTO API, use MessageHandle.dump(...) to display message contents.

The format of the generated output is:

<field>:                              <value>

For example, a message part, such as a message header field like SenderId, is displayed as:

SenderId:                             mySenderID

If a message part is present in the message, but it contains NULL or an empty string, the field is displayed (in this case, SenderID:) but no value is present. If a message part is not present, then no output is generated for that part. For example, if there is no SenderId header field, then no SenderId field or value is generated.

Freeing Messages

When using the Solace Java RTO API, a client should free a message when it is finished with it so that the memory allocated to the message is freed. Clients should free outbound messages after publishing them, and free inbound messages after they finish processing them.

A client may call MessageHandle.takeRxMessage() to take ownership of messages received in a callback. When this happens, the client must free the message when it is no longer needed.

Use MessageHandle.destroy() to free messages.

When this call successfully returns, the memory that was referenced by the freed message is no longer valid.