Package org.springframework.webflow.execution

Interface RequestContext

All Known Subinterfaces:
RequestControlContext
All Known Implementing Classes:
MockRequestContext, MockRequestControlContext
public interface RequestContext
A context for a single request to manipulate a flow execution. Allows Web Flow users to access contextual information about the executing request, as well as the governing active flow execution.

The term request is used to describe a single call (thread) into the flow system by an external actor to manipulate exactly one flow execution.

A new instance of this object is typically created when one of the core operations supported by a flow execution is invoked, either start to launch the flow execution, signalEvent to resume the flow execution, or refresh to reconstitute the flow execution's last view selection for purposes of reissuing a user response.

Once created this context object is passed around throughout flow execution request processing where it may be accessed and reasoned upon by SWF-internal artifacts such as states, user-implemented action code, and state transition criteria.

When a call into a flow execution returns this object goes out of scope and is disposed of automatically. Thus a request context is an internal artifact used within a FlowExecution: this object is not exposed to external client code, e.g. a view implementation (JSP).

The requestScope property may be used as a store for arbitrary data that should exist for the life of this object.

The web flow system will ensure that a RequestContext object is local to the current thread. It can be safely manipulated without needing to worry about concurrent access.

Note: this request context is in no way linked to an HTTP request. It uses the familiar "request" naming convention to indicate a single call to manipulate a runtime execution of a flow definition.

Author:
Keith Donald, Erwin Vervaet

  • Method Details

    • getActiveFlow

      FlowDefinition getActiveFlow() throws IllegalStateException
      Returns the definition of the flow that is currently executing.
      Returns:
      the flow definition for the active session
      Throws:
      IllegalStateException - if the flow execution is not active
      See Also:

    • getCurrentState

      StateDefinition getCurrentState() throws IllegalStateException
      Returns the current state of the executing flow. Returns null if the active flow's start state has not yet been entered.
      Returns:
      the current state, or null if in the process of starting
      Throws:
      IllegalStateException - if this flow execution is not active
      See Also:

    • getMatchingTransition

      TransitionDefinition getMatchingTransition(String eventId) throws IllegalStateException
      Returns the transition that would execute on the occurrence of the given event.
      Parameters:
      eventId - the id of the user event
      Returns:
      the transition that would trigger, or null if no transition matches
      Throws:
      IllegalStateException - if this flow execution is not active
      See Also:

    • inViewState

      boolean inViewState()
      Returns true if the flow is currently active and in a view state. When in a view state getViewScope(), can be safely called.
      Returns:
      true if in a view state, false if not
      See Also:

    • getRequestScope

      MutableAttributeMap<Object> getRequestScope()
      Returns a mutable map for accessing and/or setting attributes in request scope. Request scoped attributes exist for the duration of this request only.
      Returns:
      the request scope

    • getFlashScope

      MutableAttributeMap<Object> getFlashScope()
      Returns a mutable map for accessing and/or setting attributes in flash scope. Flash scoped attributes exist until the next event is signaled in the flow execution.
      Returns:
      the flash scope

    • getViewScope

      MutableAttributeMap<Object> getViewScope() throws IllegalStateException
      Returns a mutable map for accessing and/or setting attributes in view scope. View scoped attributes exist for the life of the current view state.
      Returns:
      the view scope
      Throws:
      IllegalStateException - if this flow is not in a view-state or the flow execution is not active
      See Also:

    • getFlowScope

      MutableAttributeMap<Object> getFlowScope() throws IllegalStateException
      Returns a mutable map for accessing and/or setting attributes in flow scope. Flow scoped attributes exist for the life of the active flow session.
      Returns:
      the flow scope
      Throws:
      IllegalStateException - if the flow execution is not active
      See Also:

    • getConversationScope

      MutableAttributeMap<Object> getConversationScope()
      Returns a mutable accessor for accessing and/or setting attributes in conversation scope. Conversation scoped attributes exist for the life of the executing flow and are shared across all flow sessions.
      Returns:
      the conversation scope
      See Also:

    • getRequestParameters

      ParameterMap getRequestParameters()
      Returns the immutable input parameters associated with this request into Spring Web Flow. The map returned is immutable and cannot be changed.

      This is typically a convenient shortcut for accessing the ExternalContext.getRequestParameterMap() directly.

      See Also:

    • getExternalContext

      ExternalContext getExternalContext()
      Returns the external client context that originated (or triggered) this request.

      Acting as a facade, the returned context object provides a single point of access to the calling client's environment. It provides normalized access to attributes of the client environment without tying you to specific constructs within that environment.

      In addition, this context may be downcastable to a specific context type for a specific client environment, such as Servlets. Such downcasting will give you full access to a native HttpServletRequest, for example. With that said, for portability reasons you should avoid coupling your flow artifacts to a specific deployment environment when possible.

      Returns:
      the originating external context, the one that triggered the current execution request

    • getMessageContext

      MessageContext getMessageContext()
      Returns the message context of this request. Useful for recording messages during the course of flow execution for display to the client.
      Returns:
      the message context

    • getFlowExecutionContext

      FlowExecutionContext getFlowExecutionContext()
      Returns contextual information about the flow execution itself. Information in this context typically spans more than one request.
      Returns:
      the flow execution context

    • getCurrentEvent

      Event getCurrentEvent()
      Returns the current event being processed by this flow. The event may or may not have caused a state transition to happen.
      Returns:
      the current event, or null if no event has been signaled yet

    • getCurrentTransition

      TransitionDefinition getCurrentTransition()
      Returns the current transition executing in this request.
      Returns:
      the current transition, or null if no transition has occurred yet

    • getCurrentView

      View getCurrentView()
      Returns the current view in use; if not null, the view returned is about to be rendered, is rendering, is processing a user event, or has finished user event processing and the current ViewState is exiting due to a state transition. Returns null if the flow is not in a view state.
      Returns:
      the current view, or null if the flow is not in a view state

    • getAttributes

      MutableAttributeMap<Object> getAttributes()
      Returns a context map for accessing attributes about the state of the current request. These attributes may be used to influence flow execution behavior.
      Returns:
      the current attributes of this request, or empty if none are set

    • getFlowExecutionUrl

      String getFlowExecutionUrl() throws IllegalStateException
      Returns the URL of this flow execution. Needed by response writers that write out the URL of this flow execution to allow calling back this execution in a subsequent request.
      Returns:
      the flow execution URL
      Throws:
      IllegalStateException - if the flow execution has not yet had its key assigned