Package org.springframework.webflow.engine.support

Class TransitionExecutingFlowExecutionExceptionHandler

java.lang.Object

org.springframework.webflow.engine.support.TransitionExecutingFlowExecutionExceptionHandler

All Implemented Interfaces:

FlowExecutionExceptionHandler

public class TransitionExecutingFlowExecutionExceptionHandler
extends Object
implements FlowExecutionExceptionHandler

A flow execution exception handler that maps the occurrence of a specific type of exception to a transition to a new State.

The handled FlowExecutionException will be exposed in flash scope as FLOW_EXECUTION_EXCEPTION_ATTRIBUTE. The underlying root cause of that exception will be exposed in flash scope as ROOT_CAUSE_EXCEPTION_ATTRIBUTE.

Author:

Keith Donald

Field Summary

Fields

Modifier and Type	Field	Description
static final String	FLOW_EXECUTION_EXCEPTION_ATTRIBUTE	The name of the attribute to expose a handled exception under in flash scope ("flowExecutionException").
static final String	ROOT_CAUSE_EXCEPTION_ATTRIBUTE	The name of the attribute to expose a root cause of a handled exception under in flash scope ("rootCauseException").

Constructor Summary

Constructors

Constructor	Description
TransitionExecutingFlowExecutionExceptionHandler()

Method Summary

Modifier and Type	Method	Description
TransitionExecutingFlowExecutionExceptionHandler	add(Class<? extends Throwable> exceptionClass, String targetStateId)	Adds an exception-to-target state mapping to this handler.
TransitionExecutingFlowExecutionExceptionHandler	add(Class<? extends Throwable> exceptionClass, TargetStateResolver targetStateResolver)	Adds a exception-to-target state resolver mapping to this handler.
boolean	canHandle(FlowExecutionException e)	Can this handler handle the given exception?
protected void	exposeException(RequestContext context, FlowExecutionException exception, Throwable rootCause)	Exposes the given flow exception and root cause in flash scope to make them available for response rendering.
ActionList	getActionList()	Returns the list of actions to execute when this handler handles an exception.
protected TargetStateResolver	getTargetStateResolver(Throwable e)	Find the mapped target state resolver for given exception.
void	handle(FlowExecutionException exception, RequestControlContext context)	Handle the exception in the context of the current request.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

FLOW_EXECUTION_EXCEPTION_ATTRIBUTE

public static final String FLOW_EXECUTION_EXCEPTION_ATTRIBUTE

The name of the attribute to expose a handled exception under in flash scope ("flowExecutionException").

See Also:

• Constant Field Values

ROOT_CAUSE_EXCEPTION_ATTRIBUTE

public static final String ROOT_CAUSE_EXCEPTION_ATTRIBUTE

The name of the attribute to expose a root cause of a handled exception under in flash scope ("rootCauseException").

See Also:

• Constant Field Values

Constructor Details

TransitionExecutingFlowExecutionExceptionHandler

public TransitionExecutingFlowExecutionExceptionHandler()

Method Details

add

public TransitionExecutingFlowExecutionExceptionHandler add(Class<? extends Throwable> exceptionClass,
 String targetStateId)

Adds an exception-to-target state mapping to this handler.

Parameters:

exceptionClass - the type of exception to map

targetStateId - the id of the state to transition to if the specified type of exception is handled

Returns:

this handler, to allow for adding multiple mappings in a single statement

add

public TransitionExecutingFlowExecutionExceptionHandler add(Class<? extends Throwable> exceptionClass,
 TargetStateResolver targetStateResolver)

Adds a exception-to-target state resolver mapping to this handler.

Parameters:

exceptionClass - the type of exception to map

targetStateResolver - the resolver to calculate the state to transition to if the specified type of exception is handled

Returns:

this handler, to allow for adding multiple mappings in a single statement

getActionList

public ActionList getActionList()

Returns the list of actions to execute when this handler handles an exception. The returned list is mutable.

canHandle

public boolean canHandle(FlowExecutionException e)

Description copied from interface: FlowExecutionExceptionHandler

Can this handler handle the given exception?

Specified by:

canHandle in interface FlowExecutionExceptionHandler

Parameters:

e - the exception that occurred

Returns:

true if yes, false if no

handle

public void handle(FlowExecutionException exception,
 RequestControlContext context)

Description copied from interface: FlowExecutionExceptionHandler

Handle the exception in the context of the current request. An implementation is expected to transition the flow to a state using RequestControlContext.execute(Transition).

Specified by:

handle in interface FlowExecutionExceptionHandler

Parameters:

exception - the exception that occurred

context - the execution control context for this request

exposeException

protected void exposeException(RequestContext context,
 FlowExecutionException exception,
 Throwable rootCause)

Exposes the given flow exception and root cause in flash scope to make them available for response rendering. Subclasses can override this if they want to expose the exceptions in a different way or do special processing before the exceptions are exposed.

Parameters:

context - the request control context

exception - the exception being handled

rootCause - root cause of the exception being handled (could be null)

getTargetStateResolver

protected TargetStateResolver getTargetStateResolver(Throwable e)

Find the mapped target state resolver for given exception. Returns null if no mapping can be found for given exception. Will try all exceptions in the exception cause chain.

toString

public String toString()

Overrides:

toString in class Object