JSF

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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