http://jira.springframework.org/browse/SWF-632

spring-webflow/src/main/java/org/springframework/webflow/engine/support/ActionExecutingViewFactory.java

@@ -15,6 +15,9 @@
  */
 package org.springframework.webflow.engine.support;
 
+import java.util.Iterator;
+
+import org.springframework.webflow.core.collection.ParameterMap;
 import org.springframework.webflow.engine.ActionExecutor;
 import org.springframework.webflow.execution.Action;
 import org.springframework.webflow.execution.Event;
@@ -53,29 +56,81 @@ public class ActionExecutingViewFactory implements ViewFactory {
 
 		private Action action;
 
-		private RequestContext context;
+		private RequestContext requestContext;
 
-		private ActionExecutingView(Action action, RequestContext context) {
+		private String eventId;
+
+		private ActionExecutingView(Action action, RequestContext requestContext) {
 			this.action = action;
-			this.context = context;
+			this.requestContext = requestContext;
 		}
 
 		public void render() {
 			if (action != null) {
-				ActionExecutor.execute(action, context);
+				ActionExecutor.execute(action, requestContext);
 			}
 		}
 
 		public void processUserEvent() {
-
+			determineEventId(requestContext);
 		}
 
 		public boolean hasFlowEvent() {
-			return context.getExternalContext().getRequestParameterMap().contains("_eventId");
+			return eventId != null;
 		}
 
 		public Event getFlowEvent() {
-			return new Event(this, context.getExternalContext().getRequestParameterMap().get("_eventId"));
+			if (!hasFlowEvent()) {
+				return null;
+			}
+			return new Event(this, eventId);
+		}
+
+		private void determineEventId(RequestContext context) {
+			eventId = findParameter("_eventId", context.getRequestParameters());
+		}
+
+		/**
+		 * Obtain a named parameter from the request parameters. This method will try to obtain a parameter value using
+		 * the following algorithm:
+		 * <ol>
+		 * <li>Try to get the parameter value using just the given <i>logical</i> name. This handles parameters of the
+		 * form <tt>logicalName = value</tt>. For normal parameters, e.g. submitted using a hidden HTML form field,
+		 * this will return the requested value.</li>
+		 * <li>Try to obtain the parameter value from the parameter name, where the parameter name in the request is of
+		 * the form <tt>logicalName_value = xyz</tt> with "_" being the configured delimiter. This deals with
+		 * parameter values submitted using an HTML form submit button.</li>
+		 * <li>If the value obtained in the previous step has a ".x" or ".y" suffix, remove that. This handles cases
+		 * where the value was submitted using an HTML form image button. In this case the parameter in the request
+		 * would actually be of the form <tt>logicalName_value.x = 123</tt>. </li>
+		 * </ol>
+		 * @param logicalParameterName the <i>logical</i> name of the request parameter
+		 * @param parameters the available parameter map
+		 * @return the value of the parameter, or <code>null</code> if the parameter does not exist in given request
+		 */
+		private String findParameter(String logicalParameterName, ParameterMap parameters) {
+			// first try to get it as a normal name=value parameter
+			String value = parameters.get(logicalParameterName);
+			if (value != null) {
+				return value;
+			}
+			// if no value yet, try to get it as a name_value=xyz parameter
+			String prefix = logicalParameterName + "_";
+			Iterator paramNames = parameters.asMap().keySet().iterator();
+			while (paramNames.hasNext()) {
+				String paramName = (String) paramNames.next();
+				if (paramName.startsWith(prefix)) {
+					String strValue = paramName.substring(prefix.length());
+					// support images buttons, which would submit parameters as
+					// name_value.x=123
+					if (strValue.endsWith(".x") || strValue.endsWith(".y")) {
+						strValue = strValue.substring(0, strValue.length() - 2);
+					}
+					return strValue;
+				}
+			}
+			// we couldn't find the parameter value
+			return null;
 		}
 
 	}

spring-webflow/src/test/java/org/springframework/webflow/engine/support/ActionExecutingViewFactoryTests.java

@@ -0,0 +1,63 @@
+package org.springframework.webflow.engine.support;
+
+import java.io.IOException;
+
+import junit.framework.TestCase;
+
+import org.springframework.webflow.execution.TestAction;
+import org.springframework.webflow.execution.View;
+import org.springframework.webflow.test.MockRequestContext;
+
+public class ActionExecutingViewFactoryTests extends TestCase {
+
+	public void testGetView() throws Exception {
+		TestAction action = new TestAction();
+		ActionExecutingViewFactory factory = new ActionExecutingViewFactory(action);
+		MockRequestContext context = new MockRequestContext();
+		View view = factory.getView(context);
+		assertFalse(action.isExecuted());
+		view.render();
+		assertTrue(action.isExecuted());
+	}
+
+	public void testProcessUserEvent() throws IOException {
+		TestAction action = new TestAction();
+		ActionExecutingViewFactory factory = new ActionExecutingViewFactory(action);
+		MockRequestContext context = new MockRequestContext();
+		View view = factory.getView(context);
+		assertFalse(action.isExecuted());
+		view.render();
+		assertTrue(action.isExecuted());
+		context.putRequestParameter("_eventId", "foo");
+		view.processUserEvent();
+		assertTrue(view.hasFlowEvent());
+		assertEquals("foo", view.getFlowEvent().getId());
+	}
+
+	public void testProcessUserEventButton() throws IOException {
+		TestAction action = new TestAction();
+		ActionExecutingViewFactory factory = new ActionExecutingViewFactory(action);
+		MockRequestContext context = new MockRequestContext();
+		View view = factory.getView(context);
+		assertFalse(action.isExecuted());
+		view.render();
+		assertTrue(action.isExecuted());
+		context.putRequestParameter("_eventId_foo", "doesn't matter");
+		view.processUserEvent();
+		assertTrue(view.hasFlowEvent());
+		assertEquals("foo", view.getFlowEvent().getId());
+	}
+
+	public void testProcessUserEventNoEvent() throws IOException {
+		TestAction action = new TestAction();
+		ActionExecutingViewFactory factory = new ActionExecutingViewFactory(action);
+		MockRequestContext context = new MockRequestContext();
+		View view = factory.getView(context);
+		assertFalse(action.isExecuted());
+		view.render();
+		assertTrue(action.isExecuted());
+		view.processUserEvent();
+		assertFalse(view.hasFlowEvent());
+		assertNull(view.getFlowEvent());
+	}
+}