Oracle8i Application Developer's Guide - XML Release 3 (8.1.7) Part Number A86030-01 |
Library | Service | Contents | Index

Personalizing Data Display With XML: Portal-to-Go , 7 of 16

## Portal-to-Go Components

### Portal-to-Go Services

A Portal-to-Go service encapsulates a unit of information requested by, and delivered to, a Portal-to-Go client. Examples of services include:

- Stock quotes

- News

- Maps

- Email

You can build services from an existing Web site, a query to any database, or any XML source.

#### Master Service

A Master Service is a Portal-to-Go object that implements a service and invokes a specific adapter. The end-user typically sees a service as a menu item on a handset or a link on a Web page. End-users invoke Master Services by choosing menu items in their device interface. The Master Service returns the following kinds of data:

- Static text, such as a movie review

- An application, such as an airline booking system

#### Figure 7-2 How an End-User Sees Services as Menu Items. Master Service is Invoked When You Select a Menu Item

By mapping an Adapter to device Transformers, master services link Portal-to-Go content sources to the delivery platforms. Each Master Service is based on one Adapter. A Master Service creates its own instance of the Adapter it uses. Therefore, several services can use the same type of Adapter, and each can pass the Adapter its service-specific argument values.

### Portal-to-Go Adapters

A Portal-to-Go Adapter is a Java application that retrieves data from an external source and renders it in Portal-to-Go XML. When invoked by a Master Service, an Adapter returns an XML document that contains the service content. Adapters provide the interface between the Portal-to-Go server and the content source.

An Adapter does the following:

- Connects to a data source

- Retrieves content

- Converts the content to Portal-to-Go XML

Portal-to-Go provides pre-built Adapters for popular content sources, including Web pages and JDBC-enabled data sources, and adapters you can modify to work with other content sources.

All adapters must generate Portal-to-Go XML. This is a well-formed, valid XML document that complies with the Portal-to-Go DTD.

### Portal-to-Go Transformers

Portal-to-Go Transformers are Java programs or XSL-T stylesheets that convert an XML document into the target or another Portal-to-Go format. They can also rearrange, filter, and add text. The Transformers enable you to present content in a format best suited to your target device. Portal-to-Go supplies transformers for the following markup languages:

- WML 1.1 - The wireless markup language defined by the WAP Forum.

- Tiny HTML - A subset of HTML, suitable for handheld devices (not phones) such as Palm Pilots.

- VoxML - The Motorola markup language that enables voice interaction with applications.

- TTML - The Tagged Text Mark-up Language is a subset of HTML developed by Nokia.

- HDML - The Handheld Devices Markup Language is a simplified version of HTML designed specifically for handheld devices.

- Plain Text - Converts content for Short Message Service-capable devices and email applications.

Figure 7-3 illustrates these markup languages and their derivation.

#### Figure 7-3 Portal-to-Go Supports Several HTML- and XML-based Markup Languages

Use Transformers to optimize content presentation for any device, and support new device platforms. In most cases, you can simply modify or re-use an existing Transformer.

| Copyright © 1996-2000, Oracle Corporation. All Rights Reserved. |
Library | Service | Contents | Index