Illustrating Tapestry

Page Class

package demo;

import org.apache.tapestry.html.BasePage;

public class Home extends BasePage {

    private String userName = "Jack";

    public String getUserName() {
        return this.userName;
    }
}

Listing 3. Home.java

The last piece of our Page component is the component class – demo.Home. The component class is a JavaBeans class that typically houses the properties that supply data to the contained components. In other words, these properties typically act as foreign objects that will be bound to the parameters of the contained components. In our example, the Page component class (demo.Home) houses the userName property that supplies the name Jack to user, the contained Insert JWC, via the getUserName method. Note that the contained Insert JWC does not care where the name comes from. For all it cares, the getUserName method can get the name from a directory service, a database or a legacy system.

In addition to providing data, the component class also provides the behavior of the component via listener and lifecycle methods. The framework provides a base component class each for JWC (BaseComponent) and Page (BasePage) components that can be extended by applications. These base component classes provide the default behavior for the necessary listener and lifecycle methods thus keeping the extended classes short and simple like our example Page component class (demo.Home).

The naming convention for the component class is the name of the component itself. And thus our component class is named Home. Component classes are typically placed in the WEB-INF/classes folder under the context of the web application like any other Java web application. So, if Welcome is the context of our Welcome application, Home.class will typically to be placed under webapps/Welcome/WEB-INF/classes.

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