How to add condition based action to command button in ADF? - jsf

Question

How to navigate to the next page based on the return value from the method called inside the action attribute of the command button.
<af:button id="tt_b2"
rendered="#{attrs.nextRendered}"
partialSubmit="true"
action="#{attrs.backingBean.nextAction}"
text="Next"
disabled="#{attrs.nextDisabled}"/>
private static final String NEXT_NAVIGATION_ACTION = "controllerContext.currentViewPort.taskFlowContext.trainModel.getNext";
public String nextAction() {
if (validate()) {
updateModel();
return NEXT_NAVIGATION_ACTION;
}
return null;
}
The use case is done for train model, which is implemented based on this blog : http://javacollectibles.blogspot.co.uk/2014/10/adf-train-template.html
We need to define a generic next action in the template but the action should be called conditionally, based on whether all the validation checks has been passed on not.

Answer 1

Try using ADFUtils.invokeEl
public String nextAction() {
if (validate()) {
updateModel();
return (String)ADFUtils.invokeEL(NEXT_NAVIGATION_ACTION);
}
return null;
}

Answer 2

Its ain't necessary to hardcode any steps, you can query TaskFlowTrainModel
/**
* Navigates to the next stop in a train
* #return outcome string
*/
public String navigateNextStop() {
String nextStopAction = null;
ControllerContext controllerContext = ControllerContext.getInstance();
ViewPortContext currentViewPortCtx = controllerContext.getCurrentViewPort();
TaskFlowContext taskFlowCtx = currentViewPortCtx.getTaskFlowContext();
TaskFlowTrainModel taskFlowTrainModel = taskFlowCtx.getTaskFlowTrainModel();
TaskFlowTrainStopModel currentStop = taskFlowTrainModel.getCurrentStop();
TaskFlowTrainStopModel nextStop = taskFlowTrainModel.getNextStop(currentStop);
//is either null or has the value of outcome
return nextStopAction;
}
Full code of the sample can be found on the ADF Code Corner.
To navigate by taskflow outcomes you just need to provide exact outcome String as return of your method:
private static final String NEXT_NAVIGATION_ACTION = "next";
public String nextAction() {
if (validate()) {
updateModel();
return NEXT_NAVIGATION_ACTION;
}
return null;
}

Answer 3

Can you verify, you can do it in through phase listener.
Verify you condition in the phase listener and allow it to move ahead if it validates else stop the thread execution.
Below is the sample phase listener code.
public class MyPhaseListener implements PagePhaseListener{
public MyPhaseListener() {
super();
}
#Override
public void afterPhase(PagePhaseEvent pagePhaseEvent) {
if (pagePhaseEvent.getPhaseId() == Lifecycle.PREPARE_RENDER_ID ) {
// DO your logic here
}
}
#Override
public void beforePhase(PagePhaseEvent pagePhaseEvent) {
}
}