How to configure a global transition for a back button?

[rmh78]

Hi Oliver,

just successfully used your BackToLastViewStateFlowExecutionListener for global back transition inside my flow. Do you have also a solution for using this listender over subflows too. In my example I have one main flow (view1, view2, subflow1, view3) calling one subflow (subview1 and subview2). In this example your listender-implementation does not work because the previousViewStateId hold a view-state of the main flow which is not known inside the subflow.

Do you have any suggestions how to extend this listener?

Thanks, Harald

[leonardbutz]

Not able to find the method context.getLastEvent().It gives me compile error saying not able to find method getLastEvent()

I am using SWF 2.0.5 v. Is it same as getCurrentEvent() in SWF v2.0.5?

Thanks

Same problem here... I'm using Spring Web Flow 2.3.0...

I my webflow-config.xml I have this:

  <webflow:flow-executor id="flowExecutor" flow-registry="flowRegistry">
		<webflow:flow-execution-attributes>
			<webflow:always-redirect-on-pause value="false" />
			<!-- <webflow:redirect-in-same-state value="false"/> -->
		</webflow:flow-execution-attributes>
		<webflow:flow-execution-listeners>
			<webflow:listener ref="jpaFlowExecutionListener" />
			<webflow:listener ref="facesContextListener" />
			<webflow:listener ref="myFlowListener" />
		</webflow:flow-execution-listeners>
	</webflow:flow-executor>

myFlowListener:

package ch.itartis.relman.web.flow.listener;

import java.util.LinkedList;

import org.springframework.webflow.definition.StateDefinition;
import org.springframework.webflow.engine.ViewState;
import org.springframework.webflow.execution.FlowExecutionListenerAdapter;
import org.springframework.webflow.execution.FlowSession;
import org.springframework.webflow.execution.RequestContext;

public class myFlowListener extends FlowExecutionListenerAdapter {

	private String viewStatesName = "GLOBAL_BACK_LISTENER_VIEW_STATES";
	private String backEventId = "cancel";

	public void setViewStatesName(String viewStatesName) {
		this.viewStatesName = viewStatesName;
	}

	public void setBackEventId(String backEventId) {
		this.backEventId = backEventId;
	}

	@Override
	public void sessionStarted(final RequestContext context, final FlowSession session) {
		session.getScope().put(viewStatesName, new LinkedList<String>());
	}

	@Override
	public void stateEntered(final RequestContext context, final StateDefinition previousState,
			final StateDefinition state) {
		if (!(previousState instanceof ViewState))
			return;

		@SuppressWarnings("unchecked")
		final LinkedList<String> viewStates = (LinkedList<String>) context.getFlowScope().get(viewStatesName);

		if (viewStates == null)
			throw new IllegalStateException("viewStates is null");

		final String previousStateId;

		if (context.getCurrentEvent().getId().equals(backEventId)) {
			viewStates.removeLast();
			previousStateId = viewStates.getLast();
		} else {
			previousStateId = previousState.getId();
			viewStates.add(previousStateId);
		}

		context.getFlowScope().put("previousViewStateId", previousStateId);
	}
}

And in my mainflow, I use this as a global transition:

<transition on="cancel" to="${flowScope.previousViewStateId}"/>

The Exception I get:

14:04:23.995 [http-9080-2] DEBUG o.s.webflow.engine.Transition - Executing [Transition@efff29 on = cancel, to = ${flowScope.previousViewStateId}]
14:04:23.995 [http-9080-2] DEBUG o.s.w.engine.impl.FlowExecutionImpl - Attempting to handle [org.springframework.webflow.execution.FlowExecutionException:
Exception thrown in state 'createContact' of flow 'main'] with root cause [java.lang.IllegalArgumentException: Cannot find state with id '${flowScope.previ
ousViewStateId}' in flow 'main' -- Known state ids are 'array<String>['home', 'error', 'createContact', 'editContact', 'readContact', 'listContacts', 'cont
actConfirmed', 'createAccount', 'editAccount', 'readAccount', 'listAccounts', 'accountConfirmed']']
14:04:24.002 [http-9080-2] DEBUG o.s.w.e.s.TransitionExecutingFlowExecutionExceptionHandler - Handling flow execution exception org.springframework.webflow
.execution.FlowExecutionException: Exception thrown in state 'createContact' of flow 'main'

What am I doing wrong? Please help me.

[shanehughes]

Same problem here... I'm using Spring Web Flow 2.3.0...

And in my mainflow, I use this as a global transition:

<transition on="cancel" to="${flowScope.previousViewStateId}"/>

What am I doing wrong? Please help me.

I was suffering the same problem. The key seems to be the change in EL notation in 2.3.0 (and possibly earlier) to the use of #{...} instead of ${...} as delimiter markers. The 2.3.x documentation shows this. A simple change to the #{...} notation worked a charm for me.