This chapter includes these topics:
Table 2-1 summarizes the history of asynchronous capability in WebLogic Portal.
Ajax refers to a collection of standards-based and open source browser technologies. While a classic web application refreshes the entire web page with each response from the server, an Ajax-enabled web application allows small amounts of data and UI markup to be returned from the server and rendered in the browser without refreshing the entire page. To the user, an Ajax-enabled web application responds more smoothly and quickly than a traditional web application.
As explained in Portal-Aware XMLHttpRequest, the standard XMLHttpRequest object is not always the best solution in a portal environment.
When standard XHR objects are used in a portal environment, certain rendering, interportlet communication, and other problems can occur. XHR calls are scoped to an entire portal, while portal-aware XHR calls are scoped to individual portlets. A portal-aware XHR call retrieves some portion of a portlet’s content and of any other portlets that are affected.
The Disc API class, bea.wlp.disc.io.XMLHttpRequest, is an extension of the standard XMLHttpRequest class. WLP’s XMLHttpRequest allows you to make asynchronous, incremental calls to the portal server, and supports portal features such as interportlet communication and WSRP. For more information, see The WLP Disc Framework.
Representational State Transfer, or REST, is an architectural style for interacting with resources at a given URL. A REST architecture is typically used to provide a simple HTTP interface to resources published on the web. Although a simplistic analogy, you can think of REST services as an easy-to-use equivalent to traditional web services.
The primary advantage of using REST style services with web applications, such as WebLogic Portal, is that REST allows the web application to access web-addressed data and UI directly from the browser interface. The REST model provides a loose coupling between the data and the UI. REST services are easy to invoke using an HTTP request from a browser.
WebLogic Portal provides a REST framework that exposes WLP data and methods as REST services. These services unlock data from a portal web application and allow the data to be shared between applications. See The WebLogic Portal REST API for details.
|Tip:||For a good general introduction to REST, refer to the Wikipedia article.|