org.springframework.webflow.engine.support
Class TransitionExecutingStateExceptionHandler

java.lang.Object
  org.springframework.webflow.engine.support.TransitionExecutingStateExceptionHandler

All Implemented Interfaces:

FlowExecutionExceptionHandler

public class TransitionExecutingStateExceptionHandler
extends java.lang.Object
implements FlowExecutionExceptionHandler

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

The handled FlowExecutionException will be exposed in flash scope as STATE_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

static java.lang.String	ROOT_CAUSE_EXCEPTION_ATTRIBUTE The name of the attribute to expose a root cause of a handled exception under in flash scope ("rootCauseException").
static java.lang.String	STATE_EXCEPTION_ATTRIBUTE The name of the attribute to expose a handled exception under in flash scope ("stateException").

Constructor Summary

TransitionExecutingStateExceptionHandler()

Method Summary

TransitionExecutingStateExceptionHandler	add(java.lang.Class exceptionClass, java.lang.String targetStateId) Adds an exception->state mapping to this handler.
TransitionExecutingStateExceptionHandler	add(java.lang.Class exceptionClass, TargetStateResolver targetStateResolver) Adds a exception->state mapping to this handler.
protected void	exposeException(RequestContext context, FlowExecutionException exception, java.lang.Throwable rootCause) Exposes the given flow exception and root cause in flash scope to make them available for response rendering.
protected java.lang.Throwable	findRootCause(java.lang.Throwable t) Find the root cause of given throwable.
ActionList	getActionList() Returns the list of actions to execute when this handler handles an exception.
protected TargetStateResolver	getTargetStateResolver(FlowExecutionException e) Find the mapped target state resolver for given exception.
ViewSelection	handle(FlowExecutionException exception, RequestControlContext context) Handle the exception in the context of the current request, optionally making an error view selection that should be rendered.
boolean	handles(FlowExecutionException e) Can this handler handle the given exception?
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

STATE_EXCEPTION_ATTRIBUTE

public static final java.lang.String STATE_EXCEPTION_ATTRIBUTE

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

See Also:

Constant Field Values

ROOT_CAUSE_EXCEPTION_ATTRIBUTE

public static final java.lang.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 Detail

TransitionExecutingStateExceptionHandler

public TransitionExecutingStateExceptionHandler()

Method Detail

add

public TransitionExecutingStateExceptionHandler add(java.lang.Class exceptionClass,
                                                    java.lang.String targetStateId)

Adds an exception->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 TransitionExecutingStateExceptionHandler add(java.lang.Class exceptionClass,
                                                    TargetStateResolver targetStateResolver)

Adds a exception->state 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.

handles

public boolean handles(FlowExecutionException e)

Description copied from interface: FlowExecutionExceptionHandler

Can this handler handle the given exception?

Specified by:

handles in interface FlowExecutionExceptionHandler

Parameters:

e - the exception that occured

Returns:

true if yes, false if no

handle

public ViewSelection handle(FlowExecutionException exception,
                            RequestControlContext context)

Description copied from interface: FlowExecutionExceptionHandler

Handle the exception in the context of the current request, optionally making an error view selection that should be rendered.

Specified by:

handle in interface FlowExecutionExceptionHandler

Parameters:

exception - the exception that occured

context - the execution control context for this request

Returns:

the selected error view that should be displayed (may be null if the handler chooses not to select a view, in which case other exception handlers may be given a chance to handle the exception)

exposeException

protected void exposeException(RequestContext context,
                               FlowExecutionException exception,
                               java.lang.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)

Since:

1.0.2

getTargetStateResolver

protected TargetStateResolver getTargetStateResolver(FlowExecutionException 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.

findRootCause

protected java.lang.Throwable findRootCause(java.lang.Throwable t)

Find the root cause of given throwable.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object