Namespace com.ibm.streamsx.topology.topic

Toolkits > com.ibm.streamsx.topology 2.1.0 > com.ibm.streamsx.topology.topic

Topic based publish-subscribe model supporting a microservice architecture style for Streams applications.

Publish-subscribe Overview

Applications can publish streams to a topic name which can then be subscribed to by other applications (or even the same application).

Relationship to Export & Import

Publish-subscribe is a simplification of IBM Streams Export and Import.

Operators

• Buffered: Connect subscriber to publisher using a buffer.
• Direct: Directly connect subscriber to publisher.
• FilteredSubscribe: Filtered subscribe to a topic.
• Publish: Publish a stream to a topic.
• Subscribe: Subscribe to topics using a topic filter.

Functions

• addUDPSubscription(rstring): Take a subscription and modify it to account for parallel regions in the publisher or subscriber.
• andFilter(rstring, rstring): Return a string representation of cond1 && cond2.
• checkTopicFilter(rstring): Check a topic filter is valid.
• checkTopicName(rstring): Check a topic name is valid.
• equalsFilter(rstring, float64): Return a string representation of name == value for a float64 attribute.
• equalsFilter(rstring, int64): Return a string representation of name == value for a int64 attribute.
• equalsFilter(rstring, rstring): Return a string representation of name == value for a rstring attribute.
• getTopicSubscription(rstring): Get the subscription that matches a topic for topic based subscription.
• getTopicSubscription(rstring, boolean): Get the subscription that matches a topic for topic based subscription with explicit matching for the publisher allowing filters.
• inFilter(rstring, list<rstring>): Return a string representation of filter name in values for a rstring attribute.
• orFilter(rstring, rstring): Return a string representation of cond1 || cond2.
• setSubscribeFilter(rstring): Set filter for input port zero.
• setSubscribeSubscription(rstring): Set a subscription expression adding in UDP channel based matching if the subscriber is in a parallel region.