Overview of
Webflow and Pipeline Management

 

The Webflow and Pipeline are flexible mechanisms designed to help you manage both the presentation and business logic in your e-commerce Web site, without the need for advanced programming skills. This topic describes the high-level architecture of the Webflow and Pipeline, and provides preliminary information about how you can use these mechanisms to customize or extend the e-business site provided with BEA WebLogic Commerce Server.

This topic includes the following sections:

• High-level Architecture

• Development Roles

• Next Steps

 

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High-level Architecture

The BEA WebLogic Commerce Server design model separates presentation (such as HTML and JavaScript) from business logic (such as database updates and implementation of business rules). To create and maintain this separation, the WebLogic Commerce Server makes use of the following six technologies:

• HTML: Standard HTML supported by Netscape Navigator or Microsoft Internet Explorer. Throughout this document, the term HTML refers to both HTML and JavaScript.

• JSP Tags: Customized tags used in the J2EE platform. The WebLogic Commerce Server uses JavaServer Page (JSP) tags to add dynamic display to the HTML pages, such as displaying the name of a customer who is currently logged in.

• Pipeline Components: Discrete units of server-side business logic, such as calculating tax or commiting an order. Pipeline components can be combined into a Pipeline.

• Pipeline Session: Storage location for information about the current session (such as the current shopping cart) or more transient data (such as error messages about a customer's most recent input).

• Input Processors: Flexible mechanisms that handle form submission. Some may perform validation of customer data, but the primary role of an input processor is to store customer data into the Pipeline session for subsequent use by a Pipeline component.

• Webflow: Controls the flow of a customer's session through the pages displayed in a browser, and execution of specific pieces of business logic. Pages generate events (that is, which link or button the customer clicks) that result in the invocation of input processors and Pipelines. These in turn either succeed or generate exceptions, from which the Webflow decides which page to display or which piece of business logic to execute next.

This separation between presentation and business logic is beneficial for a number of reasons, but most importantly, it is helpful from a customization/maintenance standpoint. Different people within your organization may perform different tasks, and may specialize in a particular area. Keeping the user interface separate from the business processes and the Java programming allows your development team to accomplish more in less time, and makes it easier for members of the team to focus on their areas of expertise or interest. For a description of typical roles, see Development Roles.

Architecture Categories

The six technologies previously described can best be understood as belonging to four categories: presentation, business logic, state maintenance, and flow of control.

HTML, JSP tags, and input processors consitute the presentation portion of the system. HTML is the display language understood by most browsers. JSP tags translate information from the Pipeline session to HTML, while input processors translate form data from HTML to the Pipeline session.

The Pipeline components containing pieces of business logic have no knowledge of HTML or any of the other presentation technologies. Instead, the Pipeline session can maintain conversational state in the system. Similarly, the Webflow governs the flow of control.

Figure 1-1 illustrates how the various technology categories interact to preserve the WebLogic Commerce Server design model. Understanding this diagram is essential to understanding how to customize and extend the Webflow and Pipeline mechanisms.

Figure 1-1 Webflow and Pipeline High-level Architecture

 

As you learn more about the Webflow and Pipeline mechanisms, return to this architecture diagram. Each time you review the diagram, you will have a better understanding of the big picture.

 

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Development Roles

This document is intended for the following audiences:

• The commerce engineer/JSP content developer, who uses JSP templates and tag libraries to implement interactive Web pages to meet business requirements. This user also maintains simple configuration files.

• The business analyst, who defines the company's business protocols (processes and rules) for a business-to-consumer Web site. This user may set pricing policies and discounts, and may plan promotional advertising.

• The site administrator, who uses Commerce and Personalization Server administration screens to configure the site's rules, portals, property sets, user profiles, content delivery, and product catalog.

• The Java/EJB programmer, who creates custom code to insert in the JSP files. This user may also handle complex configuration files and write new Pipeline components or input processors.

 

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Next Steps

The BEA WebLogic Commerce Server product ships with a working e-commerce site that can easily be modified to meet your specific business requirements. Many modifications, such as changes to page layout and presentation, can be completed without any Java coding. It is expected that these changes will be performed by a commerce engineer/JSP content developer or a site administrator, who consults with a business analyst about business strategies. For detailed information about how the Webflow and Pipeline mechanisms work, see Customizing Webflow and Pipelines, in this guide. Additionally, Using the Webflow and Pipeline Editor, describes how a commerce engineer/JSP developer can use the Webflow and Pipeline Editor Administration Tool to customize and validate the webflow.properties and pipeline.properties files.

Some of the more complex modifications, such as adding a Pipeline component to use a different credit card authorization system, will require Java coding. It is expected that these changes will be performed by a Java/EJB programmer. For information about how to extend the Webflow and Pipeline, see Extending Webflow and Pipelines.

The WebLogic Commerce Server also contains a few JSP tags specifically designed to work with the Webflow and Pipeline mechanisms. You will use these JSP tags regardless of whether you are customizing or extending the Webflow and Pipeline. For detailed information about how to use the Webflow and Pipeline JSP Tags, see Webflow and Pipeline JSP Tags Library Reference.