The definition of objects for use on the view tier is conceptually platform independent. A class is defined with a variable that provides access to its instance. Then there is a question of what scope the instance would live in.

The scopes are generally application, session, request and page, in the order of their width; application scope being the widest. This is however not universal. For component platforms that keep the page state, this would be kept across requests. Furthermore, there could be a conversation scope across multiple pages. Notwithstanding, the concepts here are relatively uniform across the platforms.

Record all objects that are exposed to the view. This involves their name or handle, as used across the view tier, and the class they represent.

For JSF, the objects exposed to the view are defined in faces-config.xml file. Some of these fall into the following groups.

• managed-bean
• message-bundle
• validator
• converter

Irrespective of the kind of object, the most important information are the define-id and define-class, the rest of the attributes when applicable; the session attribute has default.

Despite the categories of objects that could be exposed to the view, as listed above, there is nothing specific that distinguishes their entries explicitly within the behavior descriptor. However, they would differ in nature, in the way that could not be mistaken.

Although, as shown above, these groups of classes are distinguishable, it is common practice to use naming convention that distinguishes them. For instance, validators could always have the type included in the names, like FormatValidator.

Managed Bean

The information needed for this declaration is easy to map from the descriptor, as shown below.

For the declarative backing bean definition, the following attributes are employed.

The corresponding entry in the JSF configuration file would be as follows:

<managed-bean>
         <managed-bean-name>customerOrderBean</managed-bean-name>
         <managed-bean-class>com.example.CustomerOrder</managed-bean-class>
         <managed-bean-scope>session</managed-bean-scope>
</managed-bean>

Resource Bundle

Another object exposed to the view is the resource bundle, used for displaying messages that could be internationalized. On the JSF, these are indistinguishable from regular objects, since the same object.property (bundle.key) is used to retrieve their contents. This actually restricts the naming convention that could be used for the key. Inclusion of additional period would be misunderstood; as the normal use is for nested objects.

The implementation entry is on the view page; which makes sense since it only related to the page. Example is shown below.

<f:loadbundle basename="LocalizationResource" var="bundle"/>

Validator

The corresponding entry in the JSF configuration file would be as follows:

<validator>
         <validator-id>FormatValidator</validator-id>
         <validator-class>com.example.FormatValidator</validator-class>
 </validator>

Converter

The corresponding entry in the JSF configuration file would be as follows:

<converter>
         <converter-id>creditCardConverter</Converter-id>
         <converter-class>com.example.CreditCardConverter</Converter-class>
</converter>