Using templates

We take a close look at using dynamic templates in this chapter, especially as the Tiles framework implements them. Tiles is a mature product and integrates well with the Struts framework. Tiles templates can even be deployed from a Struts ActionForward, eliminating a good many "red tape" files other template systems require.

• Struts and Tiles are a powerful combination. Using dynamic templates to generate presentation pages jibes well with the other programming practices involved in writing a web application. In this chapter, we show how to best combine Tiles with Struts and other assets, like CSS. After introducing Tiles, we provide a refactoring guide to help you migrate an existing product to Tiles.
• If you find that Tiles is a good match for your application, be sure to study the example application in chapter 15. See See A glossary of dynamic template terms for a glossary of some of the special terms we use in this chapter.

Combining templates, Tiles, and Struts

When HTML tables were first invented, page designers immediately adopted them as a layout mechanism. A borderless table can be used to contain other tables and content and create layouts that were otherwise impossible.

• The same idea is often used with dynamic templates. As shown in See A master template provides the layout for a page., a master template is used to provide the layout for the page and position the elements; page fragments are then included to fill in the elements. The page fragments can be included in any type of layout: those that use borderless tables, those that use <div> tags, and even very simple layouts that just stack one component over the other.

Tiles is a framework that makes using template layouts much easier through use of a simple but effective tag library. It can be used as a drop-in replacement for the Template taglib distributed with Struts 1.0 but provides more functionality. The Tiles package can be used with any JSP application.

1.0 vs 1.1

Tiles is bundled with Struts 1.1. Configuring Tiles for Struts 1.1 is covered in chapter 4. Tiles is also available for Struts 1.0. See the Extensions category on the Struts Resources page for details [ ASF , Struts].

Most often, a JSP template system will use one template for the layout and another for the fill-in components. Tiles calls these layout files Definitions. Most template systems require that an extra file be used just to specify the layout. To avoid this overhead, Tiles allows the layout Definitions to be stored as a JavaBean. What's more, there is an extension to Struts that allows Definitions to be the target of an ActionForward. This is an exciting feature, which we discuss in section 11.3.3. In section 11.5, we return to Definitions again when we walk through refactoring an existing product into a Tiles-based application using Definitions and Struts.

• But, for now, let's start at the beginning and create a new layout from scratch.