| 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.
Each action executed by this action state may be provisioned with a set of
arbitrary execution properties. These properties are made available to the
action at execution time and may be used to influence action execution
behavior.
Common action execution properties include:
| Property |
Description |
| name |
The 'name' property is used as a qualifier for an action's result event,
and is typically used to allow the flow to respond to a specific action's
outcome within a larger action chain. For example, if an action named
myAction returns a success result, a transition
that matches on event myAction.success will be searched, and
if found, executed. If this action is not assigned a name a transition for
the base success event will be searched and if found,
executed.
This is useful in situations where you want to execute actions in an ordered
chain as part of one action state, and wish to transition on the result of
the last one in the chain. For example:
<action-state id="setupForm">
<action name="setup" bean="myAction" method="setupForm"/>
<action name="referenceData" bean="myAction" method="setupReferenceData"/>
<transition on="referenceData.success" to="displayForm"/>
</action-state>
When the 'setupForm' state above is entered, the 'setup' action will execute,
followed by the 'referenceData' action. After 'referenceData' execution, the
flow will then respond to the 'referenceData.success' event by transitioning
to the 'displayForm' state. The 'setup.success' event that was signaled by
the 'setup' action will effectively be ignored. |
| method |
The 'method' property is the name of a target method on a
org.springframework.webflow.action.MultiAction to
execute. In the MultiAction scenario the named method must have the signature
public Event ${method}(RequestContext) throws Exception.
As an example of this scenario, a method property with value setupForm
would bind to a method on a MultiAction instance with the signature:
public Event setupForm(RequestContext context).
As an alternative to a MultiAction method binding, this action state may
excute a
org.springframework.webflow.action.AbstractBeanInvokingAction bean invoking action that invokes a method on a POJO (Plain Old Java Object). If the method
signature accepts arguments those arguments may be specified by using the
format:
methodName(${arg1}, ${arg2}, ...)
Argument ${expressions} are evaluated against the current
RequestContext, allowing for data stored in flow scope or
request scope to be passed as arguments to the POJO. In addition, POJO return
values may be exposed to the flow automatically. See the bean invoking action
type hierarchy for more information. |
See Also: org.springframework.webflow.execution.Action
See Also: org.springframework.webflow.action.MultiAction
See Also: org.springframework.webflow.action.AbstractBeanInvokingAction
author:
Keith Donald
author:
Erwin Vervaet |
