Messaging Overview

In TIBCO FTL, Publishers send messages and subscribers receive messages. A program can send messages, receive messages, or both. The terms publisher and subscriber refer to TIBCO FTL objects that perform these two roles within programs. Administrators can configure user permissions to publish, subscribe, or allow other functions. Entitlements can be configured for destinations to prevent users from exchanging sensitive data.

A message stream is a sequence of messages. A publisher is the source of the message stream, and a subscriber expresses interest in that stream and receives messages.

A message only carries data. A message format defines the metadata, which is the set of fields that a message can contain. The format is available to cooperating programs before they exchange messages. This approach reduces the message size, transport bandwidth, and processing time. TIBCO FTL messages do not carry destination information.

Content Matchers

Subscriber objects can specify interest in messages based on their content made up of message fields and their values. A content matcher is a pattern-matching template for message fields and values and is used to select a subset of messages from a message stream. A subscriber can have one content matcher to express interest in the subset of messages that the content matcher specifies.

Messages can match on all values (an AND match) or on one or more of the values (an OR match). For example, a subscriber could receive only messages in which the Symbol field contains the value TIBX and FOO. Or, a subscriber could receive only messages in which the Symbol field contains the value TIBX and FOO.

A subscriber without a content matcher does not filter out any messages.

Example

In the following diagram, a program's publisher object transmits a message stream with messages A, B, C, D, and E. The subscriber object has expressed interested in the message stream and receives the stream. The subscriber uses the message format to interpret the contents of the messages. The subscriber's content matcher is only interested in messages C and E, so only messages C and E are consumed by the subscriber.