Abstract: Provided are a message brokering systems, computer program products and methods for communication in a publish/subscribe environment in which publisher application programs send messages to subscriber application programs via one or more message brokers, the method comprising the following steps: responsive to receipt of a published message at a message broker, referring to characteristics of the received message and subscriber-specified quality of service requirements to determine an appropriate quality or service for onward transmission of the message; selecting a communication protocol in accordance with the determined quality of service; and transmitting the message using the selected communication protocol. Information relating to the quality of service requirements of a first message broker's subscribers is passed to other brokers and subsequently used for selection of an appropriate communication protocol for transmitting messages between the brokers.

Abstract: A method and system for preserving message order when parallel processing messages by: providing a marker (H) in each message (M) for identifying a source of messages for which it is required to preserve the message order; and dispatching (D) each message in accordance with its marker to one of a plurality of parallel processors (P1–P3) so that processing is preserved for messages processed through the plurality of parallel processors. The dispatcher (D) retains a list of all markers of messages that are being processed in parallel, and when a message becomes available to the dispatcher for processing, the dispatcher inspects the list of messages that are currently being processed to determine whether the marker of this message is in the list, and if so delays initiating parallel processing for this message until the marker is no longer in the list.