Flow depending on external parameter?

问题

I'm building a simple POC to experiment with Faces Flow.

page 1: displays a list of companies. The user selects company A then goes to page 2.
page 2: on the selected company page, the user clicks a commandLink to start a wizard to create a new employee to be added to the company A.

Behing the scenes I've got a @FlowScoped("addNewUsertoCompanyFlow") bean MyFlowBean.

In its @PostConstruct method, the MyFlowBean needs to fetch an object corresponding to the company A from a service (@Inject).

What's the right way to let MyFlowBean know about the ID of the company A so that it can fetch it from the service ?

Thanks.

回答1:

Ok, I came up with a solution. The key was not to use the flow backing bean @PostConstruct but rather use the flow initializer, where I can grab request parameters.

So I'm using some additional input in the form that will start my flow:

<h:form id="myForm" prependId="false">
    <h:commandLink value="Enter myFlow" action="my-flow"/>
    <h:inputHidden id="parameter" name="parameter" value="8"/>
</h:form>

In my flow definition I've defined an initializer for the flow, calling some method in the flow backing bean

@Produces @FlowDefinition
public Flow defineFlow(@FlowBuilderParameter FlowBuilder flowBuilder) {
String flowId = "my-flow";
    flowBuilder.id("", flowId);
    flowBuilder.initializer("#{myFlowBean.startFlow()}");
    ...
}

I've then grabbed the parameter inside the backing bean.

@Named
@FlowScoped("my-flow")
public class MyFlowBean implements Serializable {

    public void startFlow() {
        String parameter = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("parameter");
        //now do sthg with the parameter, such as fetching data from an injected service
        ....
    }
}

Of course it's also possible to do that at the flow definition level

flowBuilder.initializer("#{trainingFlowBean.startFlow(param['parameter'])}");

and just have a parameter in the startFlow method

public void startFlow(String parameter) {
    ...
}

来源：https://stackoverflow.com/questions/21183945/flow-depending-on-external-parameter

标签

jsf

parameters

jsf-2.2

faces-flow