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Break up these top level items into individual child pages.

General Questions

Limitations

How do I add new components to an existing page dynamically?

The short answer here is: you don't. The long answer here is you don't have to, to get the behavior you desire.

One of Tapestry basic values is high scalability: this is expressed in a number of ways, reflecting scalability concerns within a single server, and within a cluster of servers.

Although you code Tapestry pages and components as if they were ordinary POJOs 1 , as deployed by Tapestry they are closer to a traditional servlet: a single instance of each page services requests from multiple threads. Behind the scenes, Tapestry transforms you code, rewriting it on the fly.

What this means is that any incoming request must be handled by a single page instance. Therefore, Tapestry enforces the concept of static structure, dynamic behavior.

Tapestry provides quite a number of ways to vary what content is rendered, well beyond simple conditionals and loops. It is possible to "drag in" components from other pages when rendering a page (other FAQs will expand on this concept). The point is, that although a Tapestry page's structure is very rigid, the order in which the components of the page render does not have to be top to bottom.

Specific Errors

Why do I get a SAXParseException when I use an HTML entity, such as   in my template?

Tapestry uses a standard SAX parser to read your templates. This means that your templates must be well formed: open and close tags must balance, attribute values must be quoted, and entities must be declared. The easiest way to accomplish this is to add a DOCTYPE to your the top of your template:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
   "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

Part of the DOCTYPE is the declaration of entities such as &nbsp;.

Alternately, you can simply use the numeric version: &#160; This is the exact same character and will render identically in the browser.

Why do I get the exception "No service implements the interface org.apache.tapestry5.internal.InternalComponentResources" when trying to use the BeanEditForm component?

This can occur when you choose the wrong package for your data object, the object edited by the BeanEditForm component. If you place it in the same package as your pages, Tapestry will treat it like a page, and perform a number of transformation on it, including adding a new constructor.

Only component classes should go in the Tapestry-controlled packages (pages, components, mixins and base under your application's root package). By convention, simple data objects should go in a data package, and Hibernate entities should go in an entities package.

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  1. Plain Old Java Object. Tapestry does not require you to extend any base classes or implement any special interfaces. ↩

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