Managing Messages in the PubSub+ JCSMP API

The following sections discuss how you can manage messages when you use the PubSub+ JCSMP 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 PubSub+ 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 PubSub+ JCSMP API you can use all the XMLMessage.get*() methods. For example:

  • XMLMessage.getApplicationMessageType()

  • XMLMessage.getDeliveryMode()

  • XMLMessage.getSenderId()

For a complete list of methods, see the PubSub+ Messaging API JCSMP reference.

Setting Message Properties

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

For a complete list of message properties that can be set, see the appropriate API in the PubSub+ 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, you can use all the XMLMessage.set*() methods. For example:

  • XMLMessage.setApplicationMessageType(String id)

  • XMLMessage.setDeliveryMode(DeliveryMode mode)

  • XMLMessage.setSenderId(String senderId)

For a complete list of methods, see the PubSub+ Messaging API JCSMP reference.

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, use XMLMessage.dump()

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.