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Using Wireless Application Protocol (WAP) with WebLogic Server
This section includes the following topics:
Wireless Application Protocol (WAP) is a set of protocols that allow for the development of Internet and Web-based services for mobile phones and other mobile devices. The WAP standard was developed by the WAP Forum whose founding members include Ericsson, Motorola, Nokia, and Phone.com and addresses the limitations of mobile networks (low bandwidth, high latency, and unpredictable availability and stability) and mobile devices (limited CPU, memory, and battery life, and a simple user interface). The WAP Forum has developed their standards in such a way that they leverage and compliment existing industry standards as much as possible. The WAP standard specifies two essential elements of wireless communication: an end-to-end application protocol and an application environment, the Wireless Application Environment (WAE), based on a browser.
There are a number of products currently available that implement the end-to-end application protocol for WAP. These products, called WAP Gateways, form the connection between clients on the mobile network and applications hosted on application servers on the Internet. The WAP Gateway builds a bridge between the telecommunication and computer networks by routing requests from mobile clients to the application servers. It can be physically located in either network, though it is needed in only one of them.
This document discusses how to provide content that is suitable for WAE and how to configure and use WebLogic Server with a WAP Gateway. For general information on WAP technologies, see the Additional Resources section.
Wireless Application Environment (WAE)
WAE defines the framework for network-neutral, wireless applications for narrow-band devices. Two of the main components of WAE are Wireless Markup Language (WML) and WMLScript (WMLS).
Wireless Markup Language (WML)
WML is analogous to HTML for HTTP applications. It is an XML-based language that is specifically designed to interface with the micro-browsers that exist in WAP-enabled devices. The Wireless Markup Language Specification defines the tags and structure of a WML document.
A WML document is a collection of one or more cards. Each card is considered a well defined unit of interaction. The general rule of thumb is that a card carries enough information to fit in one screen of a mobile device. One or more cards can be logically grouped into a deck of cards. See The WAP Gateway section for information on ways to serve WML documents to mobile clients. For general information on WML, see the Additional Resources section.
WMLScript provides general scripting capability to the WAP architecture. It is designed to overcome the limitations of narrowband communication and mobile clients. While many of the services that can be used with small mobile clients can be implemented with WML, the human behavioral compatibility of scripting improves the standard browsing and presentation facilities of WML. WMLScript resides in .wmls files that can be made available to mobile clients by placing them into the document root. The document root is the root directory for files that are publicly available on WebLogic Server. For more information, see the information on directory structures in Deploying and Configuring Web Applications. For general information on WMLScript, refer to Additional Resources.
The WAP Gateway acts as the bridge between the mobile network containing mobile clients and the computer network containing application servers as shown below.
Figure 1-1 WAP Application Architecture
A WAP Gateway typically includes the following functionality:
When a mobile client sends a request to your WAP application running on WebLogic Server, the request is first routed through the WAP Gateway where it is decoded, translated to HTTP, then forwarded to the appropriate URL. The response is then re-routed back through the gateway, translated to WAP, encoded, and forward to the mobile client. This proxy architecture allows application developers to build services that are network and terminal independent.
There is a growing number of vendors that provide WAP Gateways. WebLogic Server should work with any WAP-compliant Gateway. For a current list of WAP-compliant Gateways and other WAP products, refer to the WAP Deployment Fact Sheet compiled by the WAP Forum.
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