As outlined, a flow execution can go through a number of phases throughout its lifecycle; for example, created, active, paused, ended.

Spring Web Flow gives you full control over the ability to observe the lifecycle of an executing flow by implementing a org.springframework.webflow.execution.FlowExecutionListener.

The different phases of a flow execution is shown graphically below:

Flow execution lifecycle

The configurable properties of a flow execution are summarized below:

The configurable constructs related to flow execution are shown graphically below:

Flow execution

To help illustrate testing a flow execution, first consider the following flow to search a phonebook for contacts:

Phonebook Search Flow - UML Model

Phonebook Search Flow - XML Definition

Above you see a flow with four (4) states that execute these behaviors, respectively:

From this behavior narrative the following assertable test scenarios can be extracted:

To assist with writing these assertions Spring Web Flow ships with JUnit-based flow execution test support within the org.springframwork.webflow.test package. These base test classes are indicated below:

The completed test for this example extending AbstractXmlFlowExecutionTests is shown below:

    public class SearchFlowExecutionTests extends AbstractXmlFlowExecutionTests {
	
        public void testStartFlow() {
            ViewSelection view = startFlow();
            assertCurrentStateEquals("enterCriteria");
            assertViewNameEquals("searchCriteria", view);
            assertModelAttributeNotNull("searchCriteria", view);
        }
        
        public void testCriteriaSubmitSuccess() {
            startFlow();

            Map input = new HashMap();
            input.put("firstName", "Keith");
            input.put("lastName", "Donald");
			
            // submit with valid input
            ViewSelection view = signalEvent("submit", input);
			
            assertCurrentStateEquals("displayResults");
            assertViewNameEquals("searchResults", view);
            assertModelAttributeCollectionSize(1, "results", view);
        }
	
        public void testCriteriaSubmitError() {
            startFlow();
			
            // submit with no input
            signalEvent("submit");
			
            assertCurrentStateEquals("enterCriteria");
        }
	
        public void testNewSearch() {
            testCriteriaSubmitSuccess();
            ViewSelection view = signalEvent("newSearch");
            assertCurrentStateEquals("enterCriteria");
            assertViewNameEquals("searchCriteria", view);
        }
	
        public void testSelectValidResult() {
            testCriteriaSubmitSuccess();
			
            Map input = new HashMap();
            input.put("id", "1");
            // select with valid input
            ViewSelection view = signalEvent("select", input);
			
            assertCurrentStateEquals("displayResults");
            assertViewNameEquals("searchResults", view);
            assertModelAttributeCollectionSize(1, "results", view);
        }
	
        /**
         * A stub for testing.
         */
        private PhoneBook phonebook = new ArrayListPhoneBook();
	
        @Override
        protected ExternalizedFlowDefinition getFlowDefinition() {
            File flowDir = new File("src/webapp/WEB-INF/flows");
            File file = new File(flowDir, "search-flow.xml");
            return new ExternalizedFlowDefinition(new FileSystemResource(file));
        }
		
        @Override
        protected FlowArtifactFactory createFlowArtifactFactory() {
            return new TestFlowArtifactFactory();
        }
	
        /**
         * Used to wire in test implementations of artifacts used by the flow, such
         * as the phonebook and the detail subflow
         */
        protected class TestFlowArtifactFactory extends FlowArtifactFactoryAdapter {
        
            public Action getAction(FlowArtifactParameters parameters){
                // there is only one global action used by this flow, phonebook
                return new LocalBeanInvokingAction(phonebook);
            }
	
            public Flow getSubflow(String id) {
                // there is only one subflow, detail
                Flow detail = new Flow(id);
                // test responding to finish result by stubbing detail flow
                EndState finish = new EndState(detail, "finish");
                finish.addEntryAction(new AbstractAction() {
                    public Event doExecute(RequestContext context) {
                        // test attribute mapping behavior
                        assertEquals(new Long(1), context.getFlowScope().getAttribute("id"));
                        return success();
                    }
                });
                return detail;
            }
        }
    }	    	
	    	

With a well-written flow execution test passing that covers the controller behavior scenarios possible for your flow you have concrete evidence the flow will execute as expected when deployed in container.

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