HomeApache Page 4 - Introducing Simple Components in Apache Tapestry
GuessTheWord project - Apache
In the previous article, you witnessed the interplay between a Tapestry page and its components (granted, we had only one simple component there, but you get my point). Page class, when rendering its page, finds any components mentioned in the template and asks those components to display themselves, as they know better how to do that. Components, in their turn, might need some information to display themselves, and they ask the page class to provide the necessary information by calling some of its methods.
Create a new Web Application project in exactly the same way as we have created the first project, but give it a different name – say, GuessTheWord.
Add to the project the tapestry41 library that we have created in the previous article (right-click on the Libraries folder, choose AddLibrary…).
Configure the servlet in the deployment descriptor. Again, all settings will be the same; only the name for the servlet will be different. Here is what the Servlets page of your web.xml editing tool should look like:
Also, change welcome file to app, as we did before, and delete the index.jsp file as it is not needed.
Now, create the skeletons for two Tapestry pages, i.e. all the necessary files, but without any contents. The first page is the default one, Home. As for the second, let it be named Secret.
So our task is to, first, create two HTML files, Home.html and Secret.html. Both should be located in the WEB-INF directory of the new project, and both should have the same default content created by NetBeans.
Next, create two page specification files, Home.page and Secret.page (right-click WEB-INF, New > Empty File…). As for the contents for these files, the Home.page in the previous project is empty right now (after we made that Insert an explicit component), so you can just copy its contents to both the new Home.page and the Secret.page files.
We need, however, to change the class attribute of the <page-specification> element in both files. Let it be com.devshed.tapestry.guesstheword.Home for the Home.page and com.devshed.tapestry.guesstheword.Secret for the Secret.page.
Finally, we need to create the com.devshed.tapestry.guesstheword package and two classes in it, both abstract and extending the Tapestry’s BasePage: Home and Secret. See the previous article for the details on how to create a package and a class in NetBeans. Here is the code for the Secret class; the Home one should be different only in its name (comments are not shown):
package com.devshed.tapestry.guesstheword;
import org.apache.tapestry.html.BasePage;
public abstract class Secret extends BasePage {
public Secret() {
}
}
Remember a useful shortcut: after typing in “extends BasePage”, press Ctrl-Space, and NetBeans will find the required class in the available libraries and write an import statement automatically. These new IDEs are so helpful!
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