Managing Portals

Can a development manager with experience in other Web technologies easily become a successful portal development manager? Is there anything specific that a portal development manager must know about the technology? Are the best practices in Web development applicable to portlet development? Portal development and other kinds of Web development typically include informational and functional components. The informational components are documents and content (such as hyperlinks, plain textual information, and graphics) that are placed in portlets and that can be equipped with search capabilities. These components may have capabilities for information processing, such as content management, publishing, and document management. The functional components provide access to data processing through functional portlets. Often, the two types of components reside on the same page. A typical but simplistic example would be a portlet that provides access to accounts receivable, with another portlet providing help or training on the subject of receivables. The two portlets are related and reside on the same page.

Web Service Design Issues

Web Services are gaining in popularity because of the benefits they provide. One of the major benefits is their support for interoperability in a heterogeneous environment, which leads to the capability to add systems and solutions that require different platforms. As long as the various systems are enabled for Web Services, the services can be used to facilitate interoperation. Web Services let enterprise application developers reuse and customize existing information assets. Web Services provide developers with standard ways to access middle-tier and back-end services, such as database management systems and transaction monitors, and to integrate them with other applications.

Java Server Pages (JSP)

Good Web application design always tries to separate business objects from controls and the presentation. The benefit of using Java Server Pages (JSP) is the ability to separate Web page design from functionality and content dynamics (coding).

Brief Overview Portal Application Platforms

Portal engines come in several implementations. We do not attempt to discuss them all in this book. We provide a high level overview of three architectures: WebSphere Portal for Multiplatforms 5, Apache Open source portal servers (Pluto and Jetspeed), and Sun Microsystems Sun ONE Portal Server.

Portals

In the following sections, the concepts of portals and portlets, but not the entire portlet specification, are explained. First, some fundamental aspects of portlet development need to be presented in order to ensure your understanding. We will start with some definitions pertaining to portal components. • Client’s point of view: A portal is an integrated and personalized Web-based application that provides the end user with a single point of access to a wide variety of aggregated content (data, knowledge, and services), anytime and from anywhere, using any Web-enabled client device. This definition represents the client’s view of a portal application. • Developer’s point of view: A portlet is a Java based Web component managed by a portlet container that processes requests and generates dynamic content. A portlet container provides a run time environment for portlets and manages their lifecycle.

The Foundations of XML and WSDL

XML stands for Extensible Markup Language (http://www.w3.org/XML/), and it has been adopted by industry for exchanging data in a platform, language, and protocol independent fashion. While XML has many benefits during the development stage, it has some performance disadvantages. This chapter provides a quick look at the following topics: 1. Overview of the standard and basic concepts; 2. Basic XML document structure; 3. Information about usage of Document Type Definition (DTD); 4. Structure and usage of XML Schema; and 5. Discussion about the design and performance issues when using XML documents with Web service.

Introduction

To create an initial impression of what a portal is, we can compare a portal page to the colonial window pictured on Figure 3. This window can represent a Web page, with several smaller windowpanes. We can now imagine that the user is looking at a different application through each windowpane. To extend this metaphor, we can imagine that the application behind each pane belongs to the builder and that each member of the household uses his or her personalized window, with only some panes visible to him or her. The portal is the frame that holds the window together (indeed, we will see later that it is a container); the window itself is the Web page, and the windowpanes are called portlets.

Installation and Maintenance Costs

The decision regarding which Web server, portal engine, or particular technology to use is never an independent, straightforward process. Typically, the manufacturers’ recommendations are well founded, and only very experienced implementers, or those who wish to experiment, should mix and match various products. A basic premise can be made (with some caveats) that all major Web/portal products are comparable, although not identical. Current portal implementations do not guarantee compatibility, in spite of the existing standards.

Writing Portlets

This section is intended for IT managers who need to understand the basics of developing portlets. We will take you briefly through the development cycle of a portlet: from writing the code, to compiling, up to deployment. You must start with environment set up and continue with writing, compiling, and testing the portlets.

Struts Framework

When Java servlets were first invented, many developers quickly realized that they were faster and more powerful than the standard CGI. They were also portable and extensible. But writing HTML to send to the browser in an endless stream of println() statements was not practical. The next framework — Java Server Pages (JSP) — turned servlet writing inside out. JSP allows developers to mix HTML markup with Java code, and to therefore enjoy all the advantages of servlets along with easy development with HTML. The next stage was the realization that Java Server Pages and servlets could be used in mutual cooperation in Web applications. The servlets could serve as controllers and drive control flow, and the JSPs could concentrate on producing HTML pages. This actually was the rediscovery of the classic MVC pattern that was first abstracted in the famous Smalltalk MVC framework (Burbeck, 1987).