Advanced topics
Advanced topics are those types of topic that either provide data in a tabular form, do not provide data directly, or provide additional capabilities.
- Advanced data-providing topics
- You can publish data to these topics, but they require additional configuration on the Diffusion™ server:
- Functional topics
- You cannot publish data to these topics. Instead, functional topics provide other
capabilities to subscribing clients, for example notifications. The following types of topic are functional topics:
- DEPRECATED: Paged topics
You can transmit data through these topics, but paged topics do not use the same pub-sub mechanism as publishing topics.
Paged topics have state which is stored in a tabular format, as pages of lines. Unlike publishing topics, clients do not publish updates to a paged topic to change the state. Instead clients add, update, or remove lines in the topic.
Paged topics can be ordered or unordered. You can define the ordering of a paged topic by using a user-defined comparator class that is located on the Diffusion server or by declaring the rules that are used for the ordering when you create the topic. Lines that are added to unordered paged topics are added at the end. Lines that are added to ordered paged topics are added at the position defined by the comparator or rules.
A client must subscribe to a paged topic to be able to access the data on it. However, unlike publishing topics clients do not receive updates whenever changes are made to the paged topic state. To access the data, the client must open a view on the paged topic and specify how many lines per page and what page to open the view on. The client can then page through the data. If the state of the client's current page changes, the client is notified and can choose to refresh the page.
This page last modified: 2016/09/23