Is there any better way to configure flow.xml?

[klr8]

I've updated to the code to be Spring 1.0 compatible:

package test;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.HashSet;
import java.util.Set;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.NoSuchBeanDefinitionException;
import org.springframework.core.io.FileSystemResource;
import org.springframework.webflow.definition.StateDefinition;
import org.springframework.webflow.definition.TransitionDefinition;
import org.springframework.webflow.engine.Flow;
import org.springframework.webflow.engine.Transition;
import org.springframework.webflow.engine.TransitionableState;
import org.springframework.webflow.engine.builder.BaseFlowServiceLocator;
import org.springframework.webflow.engine.builder.FlowArtifactLookupException;
import org.springframework.webflow.engine.builder.FlowAssembler;
import org.springframework.webflow.engine.builder.FlowBuilder;
import org.springframework.webflow.engine.builder.xml.XmlFlowBuilder;
import org.springframework.webflow.engine.support.EventIdTransitionCriteria;

public class SwfViz {
	
	private static Set<StateDefinition> visitedStates = new HashSet<StateDefinition>();
	private static Flow flow;

	public static void main(String[] args) {
		if (args.length != 1) {
			System.err.println("usage: SwfViz flowFileName");
		}
		else {
			flow = loadFlow(args[0]);
			printStateTransitions(flow.getStartState());
		}
	}

	private static Flow loadFlow(String flowFileName) {
		FlowBuilder builder = new XmlFlowBuilder(
				new FileSystemResource(flowFileName), 
				new BaseFlowServiceLocator() {
					@Override
					public Flow getSubflow(String id) throws FlowArtifactLookupException {
						return new Flow(id);
					}
					
					@Override
					public BeanFactory getBeanFactory() throws UnsupportedOperationException {
						return new BeanFactory() {

							public Object getBean(String name) throws BeansException {
								return new Object();
							}

							public Object getBean(String name, Class requiredType) throws BeansException {
								return Proxy.newProxyInstance(getClass().getClassLoader(), new Class[] { requiredType }, new InvocationHandler() {
									public Object invoke(Object obj, Method method, Object[] args) throws Throwable {
										return null;
									}
								});
							}

							public boolean containsBean(String name) {
								return true;
							}

							public boolean isSingleton(String name) throws NoSuchBeanDefinitionException {
								return false;
							}

							public Class getType(String name) throws NoSuchBeanDefinitionException {
								return Object.class;
							}

							public String[] getAliases(String name) {
								return new String[0];
							}
							
						};
					}
				});
		return new FlowAssembler("flow", builder).assembleFlow();
	}

	public static void printStateTransitions(StateDefinition state) {
		
		if (visitedStates.contains(state)) {
			return;
		}

		visitedStates.add(state);

		if (state instanceof TransitionableState) {
			TransitionableState transitionableState = (TransitionableState)state;
			for (TransitionDefinition transitionDefinition : transitionableState.getTransitions()) {
				Transition transition = (Transition)transitionDefinition;
				String eventId = ((EventIdTransitionCriteria)transition.getMatchingCriteria()).getEventId();
				String targetStateId = transition.getTargetStateResolver().toString();
				
				System.out.println(state.getId() + "->" + targetStateId + "[label=\"" + eventId + "\"];");
				
				printStateTransitions(flow.getState(targetStateId));
			}
		}
	}
}

For the fileupload sample application this produces the following output:

selectFile->uploadFile[label="submit"];
uploadFile->selectFile[label="success"];
uploadFile->selectFile[label="error"];

This implementation is limited though, so it will only work on basic flows:
* only EventIdTransitionCriteria are supported
* only DefaultTargetStateResolver is supported

Erwin

[klr8]

BTW: Shouldn't an XSLT transformation be able to generate something like this based on the XML flow definition?

Erwin

[jamielister]

Klr8,

I had adapted the previously posted viz code for RC3 and passed it though DOT - that worked nicely.

My compiler complains about these lines from your latest 1.0 example:

String eventId = ((EventIdTransitionCriteria)transition.getMatchingCriteria()).getEventId();
String targetStateId = transition.getTargetStateResolver().toString();

The visibility of getMatchingCriteria doesn't allow me to get the eventId. 1.0 api only allows transitions to be matched, but not inspected.



Jamie

[Keith Donald]

Jamie,

Klr8's name is Erwin just for future reference :-)

Those methods are made public again in 1.0.1 nighly. 1.0.1 will be released following 1.2.9 which is currently scheduled for mid December.

Keith

[jamielister]

Keith + Erwin, OK cool. thanks for the tip.

And thanks also for the whole Webflow thing, it's something that I've been using on several VoiceXml projects this year - it works very nicely, and brings sanity to app-navigation.

[klr8]

The methods getMatchingCriteria, getExecututionCriteria, getTargetStateResolver, and canExecute of the Transition class have been made publicin SWF 1.0.1. See JIRA issue SWF-209 for details.

I didn't notice when I posted the code since I was compiling against my local 1.0.1 snapshots.

Erwin