AbstractFlowBuilder (Spring Web Flow 1.0 API)

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org.springframework.webflow.engine.builder
Class AbstractFlowBuilder

java.lang.Object
  org.springframework.webflow.engine.builder.BaseFlowBuilder
      org.springframework.webflow.engine.builder.AbstractFlowBuilder

All Implemented Interfaces:: FlowBuilder

public abstract class AbstractFlowBuilder
extends BaseFlowBuilder
extends BaseFlowBuilder

Base class for flow builders that programmatically build flows in Java configuration code.

To give you an example of what a simple Java-based web flow builder definition might look like, the following example defines the 'dynamic' web flow roughly equivalent to the work flow statically implemented in Spring MVC's simple form controller:

 public class CustomerDetailFlowBuilder extends AbstractFlowBuilder {
        public void buildStates() {
                // get customer information
                addActionState("getDetails", action("customerAction"), transition(on(success()), to("displayDetails")));
 
                // view customer information               
                addViewState("displayDetails", "customerDetails", transition(on(submit()), to("bindAndValidate")));
 
                // bind and validate customer information updates 
                addActionState("bindAndValidate", action("customerAction"), new Transition[] {
                                transition(on(error()), to("displayDetails")), transition(on(success()), to("finish")) });
 
                // finish
                addEndState("finish");
        }
 }

What this Java-based FlowBuilder implementation does is add four states to a flow. These include a "get" ActionState (the start state), a ViewState state, a "bind and validate" ActionState, and an end marker state (EndState).

The first state, an action state, will be assigned the indentifier getDetails. This action state will automatically be configured with the following defaults:

The action instance with id customerAction. This is the Action implementation that will execute when this state is entered. In this example, that Action will go out to the DB, load the Customer, and put it in the Flow's request context.
A success transition to a default view state, called displayDetails. This means when the Action returns a success result event (aka outcome), the displayDetails state will be entered.
It will act as the start state for this flow (by default, the first state added to a flow during the build process is treated as the start state).

The second state, a view state, will be identified as displayDetails. This view state will automatically be configured with the following defaults:

A view name called customerDetails. This is the logical name of a view resource. This logical view name gets mapped to a physical view resource (jsp, etc.) by the calling front controller (via a Spring view resolver, or a Struts action forward, for example).
A submit transition to a bind and validate action state, indentified by the default id bindAndValidate. This means when a submit event is signaled by the view (for example, on a submit button click), the bindAndValidate action state will be entered and the bindAndValidate method of the customerAction Action implementation will be executed.

The third state, an action state, will be indentified as bindAndValidate. This action state will automatically be configured with the following defaults:

An action bean named customerAction -- this is the name of the Action implementation exported in the application context that will execute when this state is entered. In this example, the Action has a "bindAndValidate" method that will bind form input in the HTTP request to a backing Customer form object, validate it, and update the DB.
A success transition to a default end state, called finish. This means if the Action returns a success result, the finish end state will be transitioned to and the flow will terminate.
An error transition back to the form view. This means if the Action returns an error event, the displayDetails view state will be transitioned back to.

The fourth and last state, an end state, will be indentified with the default end state id finish. This end state is a marker that signals the end of the flow. When entered, the flow session terminates, and if this flow is acting as a root flow in the current flow execution, any flow-allocated resources will be cleaned up. An end state can optionally be configured with a logical view name to forward to when entered. It will also trigger a state transition in a resuming parent flow if this flow was participating as a spawned 'subflow' within a suspended parent flow.

Author:: Keith Donald, Erwin Vervaet

Constructor Summary
`protected`	`AbstractFlowBuilder()` Default constructor for subclassing.
`protected`	`AbstractFlowBuilder(FlowServiceLocator flowServiceLocator)` Create an instance of an abstract flow builder, using the specified locator to obtain needed flow services at build time.

Method Summary
`protected Action`	`action(org.springframework.binding.expression.Expression expression)` Creates an evaluate action that evaluates the expression when executed.
`protected Action`	`action(org.springframework.binding.expression.Expression expression, ActionResultExposer resultExposer)` Creates an evaluate action that evaluates the expression when executed.
`protected Action`	`action(java.lang.String id)` Resolves the action with the specified id.
`protected Action`	`action(java.lang.String beanId, org.springframework.binding.method.MethodSignature methodSignature)` Creates a bean invoking action that invokes the method identified by the signature on the bean associated with the action identifier.
`protected Action`	`action(java.lang.String beanId, org.springframework.binding.method.MethodSignature methodSignature, ActionResultExposer resultExposer)` Creates a bean invoking action that invokes the method identified by the signature on the bean associated with the action identifier.
`protected java.lang.String`	`add()` Creates the `add` event id.
`protected State`	`addActionState(java.lang.String stateId, Action[] entryActions, Action[] actions, Transition[] transitions, FlowExecutionExceptionHandler[] exceptionHandlers, Action[] exitActions, AttributeMap attributes)` Adds an action state to the flow built by this builder.
`protected State`	`addActionState(java.lang.String stateId, Action action, Transition transition)` Adds an action state to the flow built by this builder.
`protected State`	`addActionState(java.lang.String stateId, Action action, Transition[] transitions)` Adds an action state to the flow built by this builder.
`protected State`	`addActionState(java.lang.String stateId, Action action, Transition transition, FlowExecutionExceptionHandler exceptionHandler)` Adds an action state to the flow built by this builder.
`protected State`	`addDecisionState(java.lang.String stateId, Action[] entryActions, Transition[] transitions, FlowExecutionExceptionHandler[] exceptionHandlers, Action[] exitActions, AttributeMap attributes)` Adds a decision state to the flow built by this builder.
`protected State`	`addDecisionState(java.lang.String stateId, Transition[] transitions)` Adds a decision state to the flow built by this builder.
`protected State`	`addDecisionState(java.lang.String stateId, TransitionCriteria decisionCriteria, java.lang.String trueStateId, java.lang.String falseStateId)` Adds a decision state to the flow built by this builder.
`protected State`	`addEndState(java.lang.String stateId)` Adds an end state to the flow built by this builder.
`protected State`	`addEndState(java.lang.String stateId, Action[] entryActions, ViewSelector viewSelector, org.springframework.binding.mapping.AttributeMapper outputMapper, FlowExecutionExceptionHandler[] exceptionHandlers, AttributeMap attributes)` Adds an end state to the flow built by this builder.
`protected State`	`addEndState(java.lang.String stateId, java.lang.String viewName)` Adds an end state to the flow built by this builder.
`protected State`	`addEndState(java.lang.String stateId, java.lang.String viewName, org.springframework.binding.mapping.AttributeMapper outputMapper)` Adds an end state to the flow built by this builder.
`protected State`	`addSubflowState(java.lang.String stateId, Action[] entryActions, Flow subflow, FlowAttributeMapper attributeMapper, Transition[] transitions, FlowExecutionExceptionHandler[] exceptionHandlers, Action[] exitActions, AttributeMap attributes)` Adds a subflow state to the flow built by this builder.
`protected State`	`addSubflowState(java.lang.String stateId, Flow subflow, FlowAttributeMapper attributeMapper, Transition transition)` Adds a subflow state to the flow built by this builder.
`protected State`	`addSubflowState(java.lang.String stateId, Flow subflow, FlowAttributeMapper attributeMapper, Transition[] transitions)` Adds a subflow state to the flow built by this builder.
`protected State`	`addViewState(java.lang.String stateId, Action[] entryActions, ViewSelector viewSelector, Action[] renderActions, Transition[] transitions, FlowExecutionExceptionHandler[] exceptionHandlers, Action[] exitActions, AttributeMap attributes)` Adds a view state to the flow built by this builder.
`protected State`	`addViewState(java.lang.String stateId, java.lang.String viewName, Action renderAction, Transition transition)` Adds a view state to the flow built by this builder.
`protected State`	`addViewState(java.lang.String stateId, java.lang.String viewName, Action renderAction, Transition[] transitions)` Adds a view state to the flow built by this builder.
`protected State`	`addViewState(java.lang.String stateId, java.lang.String viewName, Transition transition)` Adds a view state to the flow built by this builder.
`protected State`	`addViewState(java.lang.String stateId, java.lang.String viewName, Transition[] transitions)` Adds a view state to the flow built by this builder.
`protected FlowAttributeMapper`	`attributeMapper(java.lang.String id)` Request that the attribute mapper with the specified name be used to map attributes between a parent flow and a spawning subflow when the subflow state being constructed is entered.
`protected java.lang.String`	`back()` Creates the `back` event id.
`protected java.lang.String`	`cancel()` Creates the `cancel` event id.
`protected java.lang.String`	`delete()` Creates the `delete` event id.
`protected java.lang.String`	`edit()` Creates the `edit` event id.
`protected java.lang.String`	`error()` Creates the `error` event id.
`protected org.springframework.binding.expression.Expression`	`expression(java.lang.String expressionString)` Parses the expression string into a evaluatable `Expression` object.
`protected java.lang.String`	`finish()` Creates the `finish` event id.
`protected Flow`	`flow(java.lang.String id)` Request that the `Flow` with the specified flowId be spawned as a subflow when the subflow state being built is entered.
`protected AttributeMap`	`flowAttributes()` Hook subclasses may override to provide additional properties for the flow built by this builder.
`EventFactorySupport`	`getEventFactorySupport()` Returns the configured event factory support helper for creating commonly used event identifiers that drive transitions created by this builder.
`protected TransitionCriteria`	`ifReturnedSuccess(Action action)` Creates a `TransitionCriteria` that will execute the specified action when the Transition is executed but before the transition's target state is entered.
`void`	`init(java.lang.String flowId, AttributeMap attributes)` Initialize this builder.
`protected AnnotatedAction`	`invoke(java.lang.String methodName, MultiAction multiAction)` Creates an annotated action decorator that instructs the specified method be invoked on the multi action when it is executed.
`protected org.springframework.binding.mapping.MappingBuilder`	`mapping()` Factory method that returns a new, fully configured mapping builder to assist with building `Mapping` objects used by a `FlowAttributeMapper` to map attributes.
`protected org.springframework.binding.method.MethodSignature`	`method(java.lang.String method)` Convert the encoded method signature string to a `MethodSignature` object.
`protected java.lang.String`	`no()` Creates the `no` event id.
`protected TransitionCriteria`	`on(java.lang.String transitionCriteriaExpression)` Creates a transition criteria that is used to match a Transition.
`protected ActionResultExposer`	`result(java.lang.String resultName)` Factory method for a `result exposer`.
`protected ActionResultExposer`	`result(java.lang.String resultName, ScopeType resultScope)` Factory method for a `result exposer`.
`protected java.lang.String`	`select()` Creates the `select` event id.
`void`	`setEventFactorySupport(EventFactorySupport eventFactorySupport)` Sets the event factory support helper to use to create commonly used event identifiers that drive transitions created by this builder.
`protected java.lang.String`	`submit()` Creates the `submit` event id.
`protected java.lang.String`	`success()` Creates the `success` event id.
`protected TargetStateResolver`	`to(java.lang.String targetStateIdExpression)` Creates a target state resolver for the given state id expression.
`protected Transition`	`transition(TransitionCriteria matchingCriteria, TargetStateResolver targetStateResolver)` Creates a new transition.
`protected Transition`	`transition(TransitionCriteria matchingCriteria, TargetStateResolver targetStateResolver, TransitionCriteria executionCriteria)` Creates a new transition.
`protected Transition`	`transition(TransitionCriteria matchingCriteria, TargetStateResolver targetStateResolver, TransitionCriteria executionCriteria, AttributeMap attributes)` Creates a new transition.
`ViewSelector`	`viewSelector(java.lang.String viewName)` Factory method that creates a view selector from an encoded view name.
`protected java.lang.String`	`yes()` Creates the `yes` event id.

Methods inherited from class org.springframework.webflow.engine.builder.BaseFlowBuilder
`buildEndActions, buildExceptionHandlers, buildGlobalTransitions, buildInlineFlows, buildInputMapper, buildOutputMapper, buildStartActions, buildStates, buildVariables, dispose, fromStringTo, fromStringTo, getFlow, getFlowServiceLocator, setFlow, setFlowServiceLocator`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

AbstractFlowBuilder

protected AbstractFlowBuilder()

Default constructor for subclassing.

AbstractFlowBuilder

protected AbstractFlowBuilder(FlowServiceLocator flowServiceLocator)

Create an instance of an abstract flow builder, using the specified locator to obtain needed flow services at build time.

Parameters:: flowServiceLocator - the locator for services needed by this builder to build its Flow

Method Detail

getEventFactorySupport

public EventFactorySupport getEventFactorySupport()

Returns the configured event factory support helper for creating commonly used event identifiers that drive transitions created by this builder.

setEventFactorySupport

public void setEventFactorySupport(EventFactorySupport eventFactorySupport)

Sets the event factory support helper to use to create commonly used event identifiers that drive transitions created by this builder.

init

public void init(java.lang.String flowId,
                 AttributeMap attributes)
          throws FlowBuilderException

Description copied from interface: FlowBuilder

Initialize this builder. This could cause the builder to open a stream to an externalized resource representing the flow definition, for example.

Specified by:: init in interface FlowBuilder
Specified by:: init in class BaseFlowBuilder

Parameters:: flowId - the identifier to assign to the flow; attributes - custom attributes to assign to the flow
Throws:: FlowBuilderException - an exception occured building the flow

flowAttributes

protected AttributeMap flowAttributes()

Hook subclasses may override to provide additional properties for the flow built by this builder. Returns a empty collection by default.

Returns:: additional properties describing the flow being built, should not return null