org.springframework.webflow.engine
Class ActionState

java.lang.Object
  org.springframework.webflow.core.AnnotatedObject
      org.springframework.webflow.engine.State
          org.springframework.webflow.engine.TransitionableState
              org.springframework.webflow.engine.ActionState

All Implemented Interfaces:

Annotated, StateDefinition, TransitionableStateDefinition

public class ActionState
extends TransitionableState

A transitionable state that executes one or more actions when entered. When the action(s) are executed this state responds to their result(s) to decide what state to transition to next.

If more than one action is configured they are executed in an ordered chain until one returns a result event that matches a state transition out of this state. This is a form of the Chain of Responsibility (CoR) pattern.

The result of an action's execution is typically the criteria for a transition out of this state. Additional information in the current RequestContext may also be tested as part of custom transitional criteria, allowing for sophisticated transition expressions that reason on contextual state.

Author:

Keith Donald, Erwin Vervaet

See Also:

Action

Field Summary

Fields inherited from class org.springframework.webflow.engine.State

logger

Fields inherited from class org.springframework.webflow.core.AnnotatedObject

CAPTION_PROPERTY, DESCRIPTION_PROPERTY

Constructor Summary

ActionState(Flow flow, java.lang.String id)
Creates a new action state.

Method Summary

protected void	appendToString(org.springframework.core.style.ToStringCreator creator) Subclasses may override this hook method to print their internal state to a string.
protected void	doEnter(RequestControlContext context) Specialization of State's doEnter template method that executes behavior specific to this state type in polymorphic fashion.
ActionList	getActionList() Returns the list of actions executable by this action state.
Transition	getRequiredTransition(RequestContext context) Get a transition in this state for given flow execution request context.

Methods inherited from class org.springframework.webflow.engine.TransitionableState

exit, getExitActionList, getTransition, getTransitions, getTransitionSet, handleEvent

Methods inherited from class org.springframework.webflow.engine.State

doPreEntryActions, enter, equals, getEntryActionList, getExceptionHandlerSet, getFlow, getId, getOwner, handleException, hashCode, isStartState, isViewState, toString

Methods inherited from class org.springframework.webflow.core.AnnotatedObject

getAttributes, getCaption, getDescription, setCaption, setDescription

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.springframework.webflow.definition.StateDefinition

getId, getOwner, isViewState

Methods inherited from interface org.springframework.webflow.core.Annotated

getAttributes, getCaption, getDescription

Constructor Detail

ActionState

public ActionState(Flow flow,
                   java.lang.String id)
            throws java.lang.IllegalArgumentException

Creates a new action state.

Parameters:

flow - the owning flow

id - the state identifier (must be unique to the flow)

Throws:

java.lang.IllegalArgumentException - when this state cannot be added to given flow, e.g. beasue the id is not unique

See Also:

getActionList()

Method Detail

getActionList

public ActionList getActionList()

Returns the list of actions executable by this action state. The returned list is mutable.

Returns:

the state action list

getRequiredTransition

public Transition getRequiredTransition(RequestContext context)
                                 throws NoMatchingTransitionException

Description copied from class: TransitionableState

Get a transition in this state for given flow execution request context. Throws and exception when there is no corresponding transition.

Overrides:

getRequiredTransition in class TransitionableState

Throws:

NoMatchingTransitionException - when a matching transition cannot be found

doEnter

protected void doEnter(RequestControlContext context)
                throws FlowExecutionException

Specialization of State's doEnter template method that executes behavior specific to this state type in polymorphic fashion.

This implementation iterates over each configured Action instance and executes it. Execution continues until an Action returns a result event that matches a transition in this request context, or the set of all actions is exhausted.

Specified by:

doEnter in class State

Parameters:

context - the control context for the currently executing flow, used by this state to manipulate the flow execution

Throws:

FlowExecutionException - if an exception occurs in this state

appendToString

protected void appendToString(org.springframework.core.style.ToStringCreator creator)

Description copied from class: State

Subclasses may override this hook method to print their internal state to a string. This default implementation does nothing.

Overrides:

appendToString in class TransitionableState

Parameters:

creator - the toString creator, to print properties to string

See Also:

State.toString()