Portal Components

A portal component is custom Java code that is executed according to user requests, and generates HTML output for display on the client. Portal components can interrogate one another, expose their properties, identify other components and respond to events. One portal component can detect the profile and properties of another component, for instance, whether a component is based on Java Server Pages (JSP), or is a Java servlet. When necessary a component can invoke and load the class file of another component.

For example, when a user requests an iView, the portal runtime (PRT) first generates a corresponding portal component, if one does not exist already. The portal component that is invoked is then returned to the PRT, before being passed on to the client.

Usually a portal component serves a specific purpose, such as generating a static list of attributes. Several portal components can be combined to create a page, define the page layout, and fill iViews with content.

There are several portal components, such as Page Builder, which assembles pages, and the logger, which is comprised of user interface messages.

You integrate JSP into a portal component in order to separate the presentation data from the content to be supplied by the Java class.

For detailed information on portal development, go to the SAP Developer Network at sdn.sap.com.

Page Builder

The Page Builder component assembles the content of a page according to the defined page layout. For example, when you run the portal for the first time, the Page Builder assembles the initial portal page, and the content of its iViews.

A portal page is comprised of the following:

·        List of possible layouts, and a default active layout

·        iViews located in the page

At design time, each page is assigned one or more layouts. Later, when iViews are added to the page, their placement is determined by the specific active page layout. This information is all stored in the Portal Content Directory (PCD).

SAP Enterprise Portal contains a set of pre-defined page layouts based on layout templates. In addition, new layouts can be developed. The definition of a layout is implemented by proprietary tags used in Java Server Pages (JSP) to define HTML elements for pages.

Layout templates are created by portal components, such as HTML-Business for Java (HTMLB). The HTMLB elements manage themes and styles, and provide a full set of easy-to-use Web controls. The Web controls describe the HTMLB controls, their types, usage, and attributes, and how to set the attributes with the JSP-tag libraries and the class libraries.

The Page Builder can assemble iViews in a page as follows:

·        Inserts the output of the iView in the HTML for the page while retrieving the iViews.

·        Alternatively, IFRAMES in the page make the request for the content of iViews either from the portal framework, or from other sources, such as Internet Transaction Server (ITS) or any Web site.

In addition, the Page Builder executes iViews in parallel and manages timeout operations for pages.