org.springframework.webflow.execution

Interface FlowExecutionListener

All Known Implementing Classes:

FlowExecutionListenerAdapter, HibernateFlowExecutionListener, JpaFlowExecutionListener, SecurityFlowExecutionListener

public interface FlowExecutionListener

Interface to be implemented by objects that wish to listen and respond to the lifecycle of flow executions.

An 'observer' that is very aspect like, allowing you to insert 'cross cutting' behavior at well-defined points within one or more well-defined flow execution lifecycles.

For example, one custom listener may apply security checks at the flow execution level, preventing a flow from starting or a state from entering if the current user does not have the necessary permissions. Another listener may track flow execution navigation history to support bread crumbs. Another may perform auditing, or setup and tear down connections to a transactional resource.

Note that flow execution listeners are registered with a flow execution when that execution is created by a factory or restored by a FlowExecutionRepository. Typically a listener will not be registered with a flow execution at runtime, when the flow execution is already active.

Author:

Keith Donald, Erwin Vervaet, Scott Andrews

See Also:

FlowDefinition, StateDefinition, FlowExecution, RequestContext, Event

Method Summary

Methods

Modifier and Type	Method and Description
void	eventSignaled(RequestContext context, Event event) Called when an event is signaled in the current state, but prior to any state transition.
void	exceptionThrown(RequestContext context, FlowExecutionException exception) Called when an exception is thrown during a flow execution, before the exception is handled by any registered handler.
void	paused(RequestContext context) Called when a flow execution is paused, for instance when it is waiting for user input (after event processing).
void	requestProcessed(RequestContext context) Called when a client request has completed processing.
void	requestSubmitted(RequestContext context) Called when any client request is submitted to manipulate this flow execution.
void	resuming(RequestContext context) Called after a flow execution is successfully reactivated after pause (but before event processing).
void	sessionCreating(RequestContext context, FlowDefinition definition) Called to indicate a new flow definition session is about to be created.
void	sessionEnded(RequestContext context, FlowSession session, java.lang.String outcome, AttributeMap<?> output) Called when a flow execution session ends.
void	sessionEnding(RequestContext context, FlowSession session, java.lang.String outcome, MutableAttributeMap<?> output) Called when the active flow execution session has been asked to end but before it has ended.
void	sessionStarted(RequestContext context, FlowSession session) Called after a new flow session has started.
void	sessionStarting(RequestContext context, FlowSession session, MutableAttributeMap<?> input) Called after a new flow session has been created but before it starts.
void	stateEntered(RequestContext context, StateDefinition previousState, StateDefinition state) Called when a state transitions, after the transition occurred.
void	stateEntering(RequestContext context, StateDefinition state) Called when a state transitions, after the transition is matched but before the transition occurs.
void	transitionExecuting(RequestContext context, TransitionDefinition transition) Called when a transition is matched but before the transition occurs.
void	viewRendered(RequestContext context, View view, StateDefinition viewState) Called after a view has completed rendering.
void	viewRendering(RequestContext context, View view, StateDefinition viewState) Called when a view is about to render in a view-state, before any render actions are executed.

Method Detail

requestSubmitted

void requestSubmitted(RequestContext context)

Called when any client request is submitted to manipulate this flow execution. This call happens before request processing.

Parameters:

context - the current flow request context

requestProcessed

void requestProcessed(RequestContext context)

Called when a client request has completed processing.

Parameters:

context - the source of the event

sessionCreating

void sessionCreating(RequestContext context,
                   FlowDefinition definition)

Called to indicate a new flow definition session is about to be created. Called before the session is created. An exception may be thrown from this method to veto the start operation. Any type of runtime exception can be used for this purpose.

Parameters:

context - the current flow request context

definition - the flow for which a new session is starting

sessionStarting

void sessionStarting(RequestContext context,
                   FlowSession session,
                   MutableAttributeMap<?> input)

Called after a new flow session has been created but before it starts. Useful for setting arbitrary attributes in the session before the flow starts.

Parameters:

context - the current flow request context

session - the session that was created

input - a mutable input map - attributes placed in this map are eligible for input mapping by the flow definition at startup

sessionStarted

void sessionStarted(RequestContext context,
                  FlowSession session)

Called after a new flow session has started. At this point the flow's start state has been entered and any other startup behaviors have been executed.

Parameters:

context - the current flow request context

session - the session that was started

eventSignaled

void eventSignaled(RequestContext context,
                 Event event)

Called when an event is signaled in the current state, but prior to any state transition.

Parameters:

context - the current flow request context

event - the event that occurred

transitionExecuting

void transitionExecuting(RequestContext context,
                       TransitionDefinition transition)

Called when a transition is matched but before the transition occurs.

Parameters:

context - the current flow request context

transition - the proposed transition

stateEntering

void stateEntering(RequestContext context,
                 StateDefinition state)
                   throws EnterStateVetoException

Called when a state transitions, after the transition is matched but before the transition occurs.

Parameters:

context - the current flow request context

state - the proposed state to transition to

Throws:

EnterStateVetoException - when entering the state is not allowed

stateEntered

void stateEntered(RequestContext context,
                StateDefinition previousState,
                StateDefinition state)

Called when a state transitions, after the transition occurred.

Parameters:

context - the current flow request context

previousState - from state of the transition

state - to state of the transition

viewRendering

void viewRendering(RequestContext context,
                 View view,
                 StateDefinition viewState)

Called when a view is about to render in a view-state, before any render actions are executed.

Parameters:

context - the current flow request context

view - the view that is about to render

viewState - the current view state

viewRendered

void viewRendered(RequestContext context,
                View view,
                StateDefinition viewState)

Called after a view has completed rendering.

Parameters:

context - the current flow request context

view - the view that rendered

viewState - the current view state

paused

void paused(RequestContext context)

Called when a flow execution is paused, for instance when it is waiting for user input (after event processing).

Parameters:

context - the current flow request context

resuming

void resuming(RequestContext context)

Called after a flow execution is successfully reactivated after pause (but before event processing).

Parameters:

context - the current flow request context

sessionEnding

void sessionEnding(RequestContext context,
                 FlowSession session,
                 java.lang.String outcome,
                 MutableAttributeMap<?> output)

Called when the active flow execution session has been asked to end but before it has ended.

Parameters:

context - the current flow request context

session - the current active session that is ending

outcome - the outcome reached by the ending session, generally the id of the terminating end-state

output - the flow output produced by the ending session, this map may be modified by this listener to affect the output returned

sessionEnded

void sessionEnded(RequestContext context,
                FlowSession session,
                java.lang.String outcome,
                AttributeMap<?> output)

Called when a flow execution session ends. If the ended session was the root session of the flow execution, the entire flow execution also ends.

Parameters:

context - the current flow request context

session - ending flow session

outcome - the outcome reached by the ended session, generally the id of the terminating end-state

output - the flow output returned by the ending session

exceptionThrown

void exceptionThrown(RequestContext context,
                   FlowExecutionException exception)

Called when an exception is thrown during a flow execution, before the exception is handled by any registered handler.

Parameters:

context - the current flow request context

exception - the exception that occurred