15.4 EventHandler Object

Superclass	forward
Subclassed By	action wizardEvent
Description	This event-handler defines how to handle an event from the containing page. Events are triggered by controls like buttons. In J2EE, where multiple events are handled on one page, an assumption is made that all events use the same request parameter (e.g. 'action=...') to signal which event handler to action. This is called the event-request-parameter and defaults to 'action'. The standard scripts map the name defined here to 'eventName' - the name of the event as submitted by the form - in component.properties. This means that scripts should use $eventName to check for the event, rather than $name. In appropriate UI platforms (e.g. J2EE/Struts, but *not* .NET) an event-handler can be designated as the default handler and will always be actioned if no other events are appropriate. If no default event-handler is set, the last event is used-as a catch-all. This also means that there is no need to set a default handler on a single-event page - it will be done for you. Event handling should only be necessary where there is server-side action to be taken; links (anchors) can be handled directly in the HTML. The constraints defined on an event-handler are only active if this event handler action is performed. The code to execute can be either auto-generated code. This can come from code generated from an included script in 'action-script'. This will be inserted to do the body of the logic. For example, the standard search page generates logic to check all the fields in a page and create a SQL statement. This also calls the session/method handler. a method to call on a session object. This is generated if the action-style is not specified and there is a session/method pair specifid. This will be accessed via a local delegate (for now). The session will be effectively stateless (the delegate will be instantiated using a null constructor). The single parameter will be the value-object from the view. embedded text (CDATA...) within the action XML element both of the above: the method is called and then the embedded text is done. The page forwards to the success-forward-page/action if this succeeds. Any further logic is done by setting the 'forward' variable in the template; this must be done in embedded text. Some forms have multiple success outcomes from a single event. For example, searches can result in a single row or multiple rows being returned. There is one predefined property - alternative-forward - that can be used to handle an alternative success outcome. If there is more that one alternative forward, then other means of selection should be used. TBD: think about adding base/implementation split in generated classes to allow embedded text to be called as an override method.
Contained Lists	1 Name   style Type   String Inherited from   businessObject:application   2 Name   rolesAllowed Type   String Inherited from   panel   3 Name   rolesBlocked Type   String Inherited from   panel   4 Name   constraint Type   constraint GenerateAllList   false
Inherited properties	name from forward.name description (base property) template (base property) jwpattern (base property) isDisabled from forward.isDisabled successForwardPage from forward.successForwardPage successForwardAction from forward.successForwardAction forwardId from forward.forwardId package from businessObject:application.package uid from businessObject:constraint.uid linkCaption from forward.linkCaption screenPosition from forward.screenPosition group from forward.group hideWhenBlocked from forward.hideWhenBlocked

15.4.1  Property 'businessMethod'

15.4.2  Property 'bean'

15.4.3  Property 'jar'

15.4.4  Property 'actionScript'

15.4.5  Property 'alternativeForwardPage'

15.4.6  Property 'alternativeForwardRequestString'

15.4.7  Property 'htmlInsert'

15.4.8  Property 'isDefaultEvent'

15.4.9  Property 'showControl'

15.4.10  Property 'loopEnd'

15.4.11  Property 'goingToDvName'

15.4.12  Property 'failureForwardPage'

15.4.13  Property 'failureForwardRequestString'

15.4.14  Property 'userNameBase'

15.4.15  Property 'text'

15.4.16  Property 'presentationStyle'

15.4.17  Property 'border'

15.4.18  Property 'margin'

15.4.19  Property 'padding'

15.4.20  Property 'color'

15.4.21  Property 'backgroundColor'

15.4.22  Property 'extraStyle'

15.4.23  Property 'height'

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