public interface TopologyDescription {
	// Other interfaces and variables within TopologyDescription are not shown here.

	interface Source extends Node {

	    String topics();
		
		Set<String> topicSet()

   		Pattern topicPattern();
	}	

	interface Sink extends Node {
	    String topic();

		// Add abstract method to return the TopicNameExtractor class in situations where dynamic routing is used.
		// Otherwise, return null.
    	TopicNameExtractor topicNameExtractor();
	}
}