Custom <af:train> model

The <af:train> component presents a series of 'stops', each representing a task in a multi-step process, carried out sequentially. This component is very useful when you need to develop a 'wizard' sort of screens.

In general, af:train is used along with taskflow where the implementation part is a cakewalk (can be done declaratively with zero effort). Sometimes you may need to customize the default behavior of the train component. ADF Faces does support this customization through the custom menu model. To learn more about this, please go through chapter 18.7 Using Train Components to Create Navigation Items for a Multi-Step Process of Web User Interface Developer's Guide.

I'm attaching a simple af:train demo using customized org.apache.myfaces.trinidad.model.ProcessMenuModel as model. This is actually a simplified version of the af:train component sample, bundled with ADF Faces Rich Client Components Demo.

A brief description of this implementation...

jspx tag snippet is shown below

 <af:train var="node" value="#{viewScope.CustomTrainModel}"
                        id="train">
   <f:facet name="nodeStamp">
     <af:commandNavigationItem text="#{node.label}"
            actionListener="#{node.doActionListener}"
            immediate="#{viewScope.CustomTrainModel.immediate}"
            disabled="#{viewScope.CustomTrainModel.readOnly}"
            visited="#{viewScope.CustomTrainModel.visited}"
            id="commandNavigationItem"/>
  </f:facet>
</af:train>

Class diagram for custom menu model

Custom menu model used for building this sample is TrainIdMenuModel class. This is subclassed from org.apache.myfaces.trinidad.model.ProcessMenuModel. Initialization logic is copied below for your reference. Please note the usage of @PostConstruct in this bean to perform the initialization.

@PostConstruct: Specifies a method that the container will invoke after resource injection is complete but before any of the component's life-cycle methods are called.

    @PostConstruct
    public void initilize() {
        /**
         * Gets the nodes for the train
         */
        List<NavigationItemId> viewEntries =
            ServiceProxy.getInsatnce().getSomeDummyNavigationItemsToTest();

        ChildPropertyTreeModel childPropertyTreeModel =
            new ChildPropertyTreeModel();
        childPropertyTreeModel.setChildProperty("children");
        childPropertyTreeModel.setWrappedData(viewEntries);

        this.setViewIdProperty("id");
        this.setWrappedData(childPropertyTreeModel);
        this.setIdKey("idTrainViewIdKey");
    }

You can download the af:train sample using custom menu model from here.

Adding listeners for each train stop

Sometimes, you may need to invoke custom actions while navigating through train stops. The below sample provides an interesting approach for this requirement. Idea is to enhance NavigationItemId's doActionListener() method, to trigger the registered action listeners. Below sample implements this use case(Please note that, this sample is just intended to give you an idea on this topic).

You can download the af:train sample using custom menu model+custom action from here.