JSF

Brings swing like programming to the web:

• set of UI components
• event driven
• component model (ability to extend)
  • buttons, tables, input, tree handling

JSF input example

• Beans are used to communicate between the interface and application
• JSF pages can be .jsp or .jsf the url convention is .faces (with mapping) (jsf require more configuration)
• Can use normal jsp or XML version

• Note handles (legitimate) beans that don't have both getters and setters

Can call methods, set parameters:

<jhtml:inputText value="#{user.name}"/>
<jhtml:commandButton value="Submit" action="#{foo.doStuff}"/>

Has support for:

• Validation
• Data conversion
• Internationalisation
• Custom components
• Different clients e.g. wml

Processing

• "Restore View" - retrieves new values, creates component tree for processing (component for each bean/action class)
• "Apply Request Values" - each bean component processes it's values
• "Process Events" - adds action to list for each event button/link
• "Process Validations" - type conversion etc
  • skips to "Render Response" on error for data re-entry - redisplays data entry page - need to display error to indicate why
• "Update Model Values" - applies the new values to the beans
• "Invoke Application" - invokes the list of actions
  • result is a string passed to the navigation handler - used to look up next page
• "Render Response"

Beans

• backing beans - beans tying behaviour to interface form
• public no arg constructor

Notation:

• ${..} immediate evaluation - on processing the page - typically JSP/JSLT
• #{..} deferred evaluation - evaluated whenever needed - typically JSF