Updated Jan 01, 2008 by m.h.shams
Labels:	Tapestry, Web, Component, Template, Layout

Component

writing a simple component for page layout.

for more about Tapestry Components go http://tapestry.apache.org/tapestry5/tapestry-core/

Web Page Layout

Suppose that you want to have same footer , header and menubar for all or a group of pages in your web application. in this case you can simply develop a Layout Component and set it as a container for application pages.

About Tapestry Components

Each Tapestry component has its Java class and optionally its Template and Message Catalogs. component class, template and message catalogs most be put in components package or its sub packages.

There is no need to tapestry components extend from special class.

Create Layout Template

after Setting Up your Tapestry Application Environment (see my Setup Wiki page for Setup Tapestry Application) in your components package create a Template File (i choose Layout.tml for its name)

put the following code in your components template :

<html xmlns:t="http://tapestry.apache.org/schema/tapestry_5_0_0.xsd">
<head>
    <title>${title}</title>
</head>
<body>
<div id="header-div">
    <h2> My Application Header</h2>
    <hr/>
</div>
<div id="body-div">
    <t:body/>
</div>
<div id="footer-div">
    <hr/>
    copyright 2000-2007 ...
</div>
</body>
</html>

- you see <t:body/> in this template. your pages template will be go here.

- you see an expression (${title}) here for page title. you most set each page title from page template.

Create Layout Class

Create a Java class(Layout.java, component class and template name most be same) in your application components package. put the following code in your class file :

    @Parameter(required = true)
    private String title;

    public void setTitle(String title) {
        this.title = title;
    }

    public String getTitle() {
        return title;
    }

- the @Parameter annotation indicate that title is a parameter and this parameter is mandatory (required=true). you most write setter and getter for change or access value of this parameter from pages and component template.

Change The Page Templates

all pages that you want to have layout most be like this :

<span t:type="layout" t:title="literal:PageTitle" xmlns:t="http://tapestry.apache.org/schema/tapestry_5_0_0.xsd">
  Page Content goes here...
</span>

for more about Tapestry Components go http://tapestry.apache.org/tapestry5/tapestry-core/

good luck.