The technology sets up a pubsub (publish/subscribe) environment within your screen. The idea is that in a mashup, where you have lots of pieces like widgets, data objects, and functions that are pieced together from multiple sites, Tibco’s mechanism enables one of the JavaScript objects to communicate and let other objects on the page subscribe and then act accordingly.
For instance, you might have a mashup that combines a dashboard showing your portfolio mashed up with a stock ticker. Using PageBus, your dashboard could subscribe to the stock ticker object on the page and update its display.
Having originated from Tibco’s portal products, Tibco released a JavaScript version as part of its own Ajax message bus product. The piece being open sourced under BSD to OpenAjax includes 90% of the technology, according to Kevin Hakman, director of General Interface for Tibco.
For instance, while the Tibco PageBus provides an option for page objects to unsubscribe to all feeds, in the piece being contributed to OpenAjax, you must unsubscribe to each feed individually. The OpenAjax Alliance wanted to keep the hub as lightweight as possible, Hakman explained.
Provision for pubsub is part of the core specification for the OpenAjax hub, which is in effect a traffic cop that is being developed as open source through the OpenAjax Alliance.
