org.springframework.webflow.execution.FlowExecutionListener Maven / Gradle / Ivy
/*
* Copyright 2002-2006 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.webflow.execution;
import org.springframework.webflow.core.collection.AttributeMap;
import org.springframework.webflow.core.collection.MutableAttributeMap;
import org.springframework.webflow.definition.FlowDefinition;
import org.springframework.webflow.definition.StateDefinition;
import org.springframework.webflow.engine.FlowExecutionExceptionHandler;
/**
* Interface to be implemented by objects that wish to listen and respond to the
* lifecycle of {@link FlowExecution flow executions}.
*
* An 'observer' that is very aspect like, allowing you to insert 'cross
* cutting' behavior at well-defined points within one or more well-defined flow
* execution lifecycles.
*
* For example, one custom listener may apply security checks at the flow
* execution level, preventing a flow from starting or a state from entering if
* the curent user does not have the necessary permissions. Another listener may
* track flow execution navigation history to support bread crumbs. Another may
* perform auditing, or setup and tear down connections to a transactional
* resource.
*
* Note that flow execution listeners are registered with a flow execution when
* that execution is created by a {@link FlowExecutionFactory factory} or
* restored by a {@link org.springframework.webflow.execution.repository.FlowExecutionRepository}.
* Typically a listener will not be registered with a flow execution at
* runtime, when the flow execution is already active.
*
* @see FlowDefinition
* @see StateDefinition
* @see FlowExecution
* @see RequestContext
* @see Event
* @see ViewSelection
*
* @author Keith Donald
* @author Erwin Vervaet
*/
public interface FlowExecutionListener {
/**
* Called when any client request is submitted to manipulate this flow
* execution. This call happens before request processing.
* @param context the source of the event
*/
public void requestSubmitted(RequestContext context);
/**
* Called when a client request has completed processing.
* @param context the source of the event
*/
public void requestProcessed(RequestContext context);
/**
* Called immediately after a start event is signaled, indicating a new
* session of the flow is starting but has not yet entered its start state.
* An exception may be thrown from this method to veto the start operation.
* Any type of runtime exception can be used for this purpose.
* @param context the source of the event
* @param definition the flow for which a new session is starting
* @param input a mutable input map to the starting flow session
*/
public void sessionStarting(RequestContext context, FlowDefinition definition, MutableAttributeMap input);
/**
* Called when a new flow session has started. At this point the start state
* has been entered.
* @param context the source of the event
*/
public void sessionStarted(RequestContext context, FlowSession session);
/**
* Called when an event is signaled in the current state, but prior to any
* state transition.
* @param context the source of the event
* @param event the event that occured
*/
public void eventSignaled(RequestContext context, Event event);
/**
* Called when a state transitions, after the transition is matched but
* before the transition occurs.
* @param context the source of the event
* @param state the proposed state to transition to
* @throws EnterStateVetoException when entering the state is not allowed
*/
public void stateEntering(RequestContext context, StateDefinition state) throws EnterStateVetoException;
/**
* Called when a state transitions, after the transition occured.
* @param context the source of the event
* @param previousState from state of the transition
* @param state to state of the transition
*/
public void stateEntered(RequestContext context, StateDefinition previousState, StateDefinition state);
/**
* Called when a flow execution is paused, for instance when it is waiting
* for user input (after event processing).
* @param context the source of the event
* @param selectedView the view that will display
*/
public void paused(RequestContext context, ViewSelection selectedView);
/**
* Called after a flow execution is successfully reactivated after pause
* (but before event processing).
* @param context the source of the event
*/
public void resumed(RequestContext context);
/**
* Called when the active flow execution session has been asked to end but
* before it has ended.
* @param context the source of the event
* @param session the current active session that is ending
* @param output the flow output produced by the ending session, this map may
* be modified by this listener to affect the output returned
*/
public void sessionEnding(RequestContext context, FlowSession session, MutableAttributeMap output);
/**
* Called when a flow execution session ends. If the ended session was the
* root session of the flow execution, the entire flow execution also ends.
* @param context the source of the event
* @param session ending flow session
* @param output final, unmodifiable output returned by the ended session
*/
public void sessionEnded(RequestContext context, FlowSession session, AttributeMap output);
/**
* Called when an exception is thrown during a flow execution, before the
* exception is handled by any registered {@link FlowExecutionExceptionHandler handler}.
* @param context the source of the exception
* @param exception the exception that occurred
*/
public void exceptionThrown(RequestContext context, FlowExecutionException exception);
}