Expert Spring MVC and Web Flow

Figure 12-2.FlowSession life cycle

Table 12-4.Status of the FlowSession

Status Meaning Event

Created The FlowSessionhas been created, Creation of a new FlowExecution.

but is not yet active.

Active The FlowSessionis currently executing. When a flow is resumed.

Paused The FlowSessionis awaiting user input. When the view is rendered.

Suspended The FlowSessionis still valid, but not active. When a new subflow is created, the

existing FlowSessionis suspended.

Ended The FlowSessionis no longer active. When the end state has been reached.

RequestContext

So far we have looked at FlowExecutionwhich represents the execution of an entire top-level

flow including any subflows that are spawned, and FlowSessionwhich represents the execu-

tion of a single flow definition. There is one final lifetimethat hasn’t yet been covered, the

lifetime of a request to manipulate a FlowExecution. This is modeled by org.springframework.

webflow.RequestContext. You may recognize this as the parameter that is passed into the

org.springframework.webflow.Action.execute()method. This object is the one that you will

probably be most familiar with if you have implemented a custom Web Flow artifact such as

FlowExecution

SessionA

SessionB

SessionC

(suspended)

(suspended)

<flow start-state=“...”>

<action-state ....>

....

</action-state>

<subflow-state ....>

<subflow-state ....>

</subflow-state ....>

</subflow-state ....>

<view-state>

....

</view-state>

</flow>

350 CHAPTER 12 ■ADVANCED SPRING WEB FLOW