reduced flow execution key length

extracted ajax handler strategy and spring javascript impl

spring-webflow/src/main/java/org/springframework/webflow/conversation/ConversationException.java

@@ -22,7 +22,7 @@ import org.springframework.webflow.core.FlowException;
  * 
  * @author Keith Donald
  */
-public abstract class ConversationException extends FlowException {
+public class ConversationException extends FlowException {
 
 	/**
 	 * Creates a conversation service exception.

spring-webflow/src/main/java/org/springframework/webflow/conversation/impl/ConversationContainer.java

@@ -50,6 +50,11 @@ class ConversationContainer implements Serializable {
 	 */
 	private List conversations;
 
+	/**
+	 * The sequence for unique conversation identifiers within this container.
+	 */
+	private int conversationIdSequence;
+
 	/**
 	 * Create a new conversation container.
 	 * @param maxConversations the maximum number of allowed concurrent conversations, -1 for unlimited
@@ -77,12 +82,11 @@ class ConversationContainer implements Serializable {
 
 	/**
 	 * Create a new conversation based on given parameters and add it to the container.
-	 * @param id the unique id of the conversation
 	 * @param parameters descriptive parameters
 	 * @return the created conversation
 	 */
-	public synchronized Conversation createAndAddConversation(ConversationId id, ConversationParameters parameters) {
-		ContainedConversation conversation = new ContainedConversation(this, id);
+	public synchronized Conversation createConversation(ConversationParameters parameters) {
+		ContainedConversation conversation = new ContainedConversation(this, nextId());
 		conversations.add(conversation);
 		if (maxExceeded()) {
 			// end oldest conversation
@@ -91,6 +95,10 @@ class ConversationContainer implements Serializable {
 		return conversation;
 	}
 
+	private ConversationId nextId() {
+		return new SimpleConversationId(Integer.valueOf(++conversationIdSequence));
+	}
+
 	/**
 	 * Return the identified conversation.
 	 * @param id the id to lookup

spring-webflow/src/main/java/org/springframework/webflow/conversation/impl/SessionBindingConversationManager.java

@@ -15,8 +15,6 @@
  */
 package org.springframework.webflow.conversation.impl;
 
-import org.apache.commons.logging.Log;
-import org.apache.commons.logging.LogFactory;
 import org.springframework.webflow.context.ExternalContextHolder;
 import org.springframework.webflow.conversation.Conversation;
 import org.springframework.webflow.conversation.ConversationException;
@@ -24,8 +22,6 @@ import org.springframework.webflow.conversation.ConversationId;
 import org.springframework.webflow.conversation.ConversationManager;
 import org.springframework.webflow.conversation.ConversationParameters;
 import org.springframework.webflow.core.collection.SharedAttributeMap;
-import org.springframework.webflow.util.RandomGuidUidGenerator;
-import org.springframework.webflow.util.UidGenerator;
 
 /**
  * Simple implementation of a conversation manager that stores conversations in the session attribute map.
@@ -40,8 +36,6 @@ import org.springframework.webflow.util.UidGenerator;
  */
 public class SessionBindingConversationManager implements ConversationManager {
 
-	private static final Log logger = LogFactory.getLog(SessionBindingConversationManager.class);
-
 	/**
 	 * The name of the session attribute that will hold the conversation container used by this conversation manager.
 	 * 
@@ -50,12 +44,7 @@ public class SessionBindingConversationManager implements ConversationManager {
 	 * value to something unique.
 	 * @see #setSessionKey(String)
 	 */
-	private String sessionKey = "webflow.conversationContainer";
-
-	/**
-	 * The conversation uid generation strategy to use.
-	 */
-	private UidGenerator conversationIdGenerator = new RandomGuidUidGenerator();
+	private String sessionKey = "webflowConversationContainer";
 
 	/**
 	 * The maximum number of active conversations allowed in a session. The default is 5. This is high enough for most
@@ -63,20 +52,6 @@ public class SessionBindingConversationManager implements ConversationManager {
 	 */
 	private int maxConversations = 5;
 
-	/**
-	 * Returns the used generator for conversation ids. Defaults to {@link RandomGuidUidGenerator}.
-	 */
-	public UidGenerator getConversationIdGenerator() {
-		return conversationIdGenerator;
-	}
-
-	/**
-	 * Sets the configured generator for conversation ids.
-	 */
-	public void setConversationIdGenerator(UidGenerator uidGenerator) {
-		this.conversationIdGenerator = uidGenerator;
-	}
-
 	/**
 	 * Returns the maximum number of allowed concurrent conversations. The default is 5.
 	 */
@@ -110,12 +85,7 @@ public class SessionBindingConversationManager implements ConversationManager {
 	}
 
 	public Conversation beginConversation(ConversationParameters conversationParameters) throws ConversationException {
-		ConversationId conversationId = new SimpleConversationId(conversationIdGenerator.generateUid());
-		if (logger.isDebugEnabled()) {
-			logger.debug("Beginning conversation " + conversationParameters + "; unique conversation id = "
-					+ conversationId);
-		}
-		return getConversationContainer().createAndAddConversation(conversationId, conversationParameters);
+		return getConversationContainer().createConversation(conversationParameters);
 	}
 
 	public Conversation getConversation(ConversationId id) throws ConversationException {
@@ -123,7 +93,17 @@ public class SessionBindingConversationManager implements ConversationManager {
 	}
 
 	public ConversationId parseConversationId(String encodedId) throws ConversationException {
-		return new SimpleConversationId(conversationIdGenerator.parseUid(encodedId));
+		try {
+			return new SimpleConversationId(Integer.valueOf(encodedId));
+		} catch (NumberFormatException e) {
+			throw new ConversationException("Unable to parse string-encoded conversationId + '" + encodedId + "'", e);
+		}
+	}
+
+	// hooks for subclassing
+
+	protected ConversationContainer createConversationContainer() {
+		return new ConversationContainer(maxConversations, sessionKey);
 	}
 
 	// internal helpers
@@ -137,7 +117,7 @@ public class SessionBindingConversationManager implements ConversationManager {
 		synchronized (sessionMap.getMutex()) {
 			ConversationContainer container = (ConversationContainer) sessionMap.get(sessionKey);
 			if (container == null) {
-				container = new ConversationContainer(maxConversations, sessionKey);
+				container = createConversationContainer();
 				sessionMap.put(sessionKey, container);
 			}
 			return container;

spring-webflow/src/main/java/org/springframework/webflow/conversation/impl/SimpleConversationId.java

@@ -21,9 +21,8 @@ import org.springframework.webflow.conversation.ConversationId;
 import org.springframework.webflow.conversation.ConversationManager;
 
 /**
- * An id that uniquely identifies a conversation managed by a {@link ConversationManager}.
- * <p>
- * This key consists of a unique string that is typically a GUID.
+ * An id that uniquely identifies a conversation managed by a {@link ConversationManager}. This key consists of a
+ * unique string that is typically a GUID.
  * 
  * @author Ben Hale
  */

spring-webflow/src/main/java/org/springframework/webflow/execution/repository/impl/DefaultFlowExecutionRepository.java

@@ -82,13 +82,22 @@ public class DefaultFlowExecutionRepository extends AbstractFlowExecutionContinu
 	}
 
 	/**
-	 * Sets the maximum number of continuations allowed per conversation in this repository. Use -1 for unlimited. The
+	 * Returns the max number of continuations allowed per conversation by this repository.
+	 */
+	public int getMaxContinuations() {
+		return maxContinuations;
+	}
+
+	/**
+	 * Sets the maximum number of continuations allowed per conversation by this repository. Use -1 for unlimited. The
 	 * default is 30.
 	 */
 	public void setMaxContinuations(int maxContinuations) {
 		this.maxContinuations = maxContinuations;
 	}
 
+	// implementing flow execution repository
+
 	public FlowExecution getFlowExecution(FlowExecutionKey key) {
 		if (logger.isDebugEnabled()) {
 			logger.debug("Getting flow execution with key '" + key + "'");
@@ -117,28 +126,14 @@ public class DefaultFlowExecutionRepository extends AbstractFlowExecutionContinu
 		putConversationScope(flowExecution);
 	}
 
-	// internal helpers
+	// hooks for subclassing
 
-	/**
-	 * Returns the continuation group associated with the governing conversation. TODO: memento persistence?
-	 * @param key the flow execution key
-	 * @return the continuation group
-	 */
-	private FlowExecutionContinuationGroup getContinuationGroup(FlowExecutionKey key) {
-		Conversation conversation = getConversation(key);
-		FlowExecutionContinuationGroup group = (FlowExecutionContinuationGroup) conversation
-				.getAttribute(CONTINUATION_GROUP_ATTRIBUTE);
-		if (group == null) {
-			// setup a new continuation group for the conversation
-			// no need to synchronize here since this code will only be executed
-			// during the launch of a new flow execution, at which time the
-			// key has not yet been communicated to any other threads
-			group = new FlowExecutionContinuationGroup(maxContinuations);
-			conversation.putAttribute(CONTINUATION_GROUP_ATTRIBUTE, group);
-		}
-		return group;
+	protected FlowExecutionContinuationGroup createFlowExecutionContinuationGroup() {
+		return new FlowExecutionContinuationGroup(maxContinuations);
 	}
 
+	// internal helpers
+
 	/**
 	 * Returns the continuation in the group with the specified key.
 	 * @param key the flow execution key
@@ -152,4 +147,20 @@ public class DefaultFlowExecutionRepository extends AbstractFlowExecutionContinu
 			throw new FlowExecutionRestorationFailureException(key, e);
 		}
 	}
+
+	/**
+	 * Returns the continuation group associated with the governing conversation.
+	 * @param key the flow execution key
+	 * @return the continuation group
+	 */
+	private FlowExecutionContinuationGroup getContinuationGroup(FlowExecutionKey key) {
+		Conversation conversation = getConversation(key);
+		FlowExecutionContinuationGroup group = (FlowExecutionContinuationGroup) conversation
+				.getAttribute(CONTINUATION_GROUP_ATTRIBUTE);
+		if (group == null) {
+			group = createFlowExecutionContinuationGroup();
+			conversation.putAttribute(CONTINUATION_GROUP_ATTRIBUTE, group);
+		}
+		return group;
+	}
 }

spring-webflow/src/main/java/org/springframework/webflow/execution/repository/impl/FlowExecutionContinuationGroup.java

@@ -92,7 +92,7 @@ class FlowExecutionContinuationGroup implements Serializable {
 			continuationIds.remove(continuationId);
 		}
 		continuationIds.add(continuationId);
-		// remove the oldest continuation if them maximium number of
+		// remove the oldest continuation if the maximium number of
 		// continuations has been exceeded
 		if (maxExceeded()) {
 			removeOldestContinuation();

spring-webflow/src/main/java/org/springframework/webflow/execution/repository/support/AbstractFlowExecutionRepository.java

@@ -38,8 +38,6 @@ import org.springframework.webflow.execution.repository.FlowExecutionLock;
 import org.springframework.webflow.execution.repository.FlowExecutionRepository;
 import org.springframework.webflow.execution.repository.FlowExecutionRepositoryException;
 import org.springframework.webflow.execution.repository.NoSuchFlowExecutionException;
-import org.springframework.webflow.util.RandomGuidUidGenerator;
-import org.springframework.webflow.util.UidGenerator;
 
 /**
  * Abstract base class for flow execution repository implementations. Does not make any assumptions about the storage
@@ -68,11 +66,6 @@ public abstract class AbstractFlowExecutionRepository implements FlowExecutionRe
 	 */
 	private FlowExecutionStateRestorer executionStateRestorer;
 
-	/**
-	 * The uid generation strategy to use.
-	 */
-	private UidGenerator continuationIdGenerator = new RandomGuidUidGenerator();
-
 	/**
 	 * Flag to indicate whether or not a new flow execution key should always be generated before each put call. Default
 	 * is true.
@@ -91,15 +84,6 @@ public abstract class AbstractFlowExecutionRepository implements FlowExecutionRe
 		this.executionStateRestorer = executionStateRestorer;
 	}
 
-	/**
-	 * Sets the uid generation strategy used to generate unique continuation identifiers for
-	 * {@link FlowExecutionKey flow execution keys}.
-	 */
-	public void setContinuationIdGenerator(UidGenerator continuationIdGenerator) {
-		Assert.notNull(continuationIdGenerator, "The continuation id generator is required");
-		this.continuationIdGenerator = continuationIdGenerator;
-	}
-
 	/**
 	 * Sets a flag indicating if a new {@link FlowExecutionKey} should always be generated before each put call. By
 	 * setting this to false a FlowExecution can remain identified by the same key throughout its life.
@@ -111,7 +95,7 @@ public abstract class AbstractFlowExecutionRepository implements FlowExecutionRe
 	public FlowExecutionKey getKey(FlowExecution execution) {
 		if (execution.getKey() == null) {
 			Conversation conversation = beginConversation(execution);
-			return new CompositeFlowExecutionKey(conversation.getId(), continuationIdGenerator.generateUid());
+			return new CompositeFlowExecutionKey(conversation.getId(), Integer.valueOf(1));
 		} else {
 			return getNextKey(execution);
 		}
@@ -120,25 +104,16 @@ public abstract class AbstractFlowExecutionRepository implements FlowExecutionRe
 	public FlowExecutionKey parseFlowExecutionKey(String encodedKey) throws FlowExecutionRepositoryException {
 		if (!StringUtils.hasText(encodedKey)) {
 			throw new BadlyFormattedFlowExecutionKeyException(encodedKey,
-					"The string encoded flow execution key is required");
+					"The string-encoded flow execution key is required");
 		}
 		String[] keyParts = CompositeFlowExecutionKey.keyParts(encodedKey);
-		// parse out the conversation id
 		ConversationId conversationId;
 		try {
 			conversationId = conversationManager.parseConversationId(keyParts[0]);
 		} catch (ConversationException e) {
-			throw new BadlyFormattedFlowExecutionKeyException(encodedKey, "The conversation id '" + keyParts[0]
-					+ "' contained in the composite flow execution key '" + encodedKey + "' is invalid", e);
-		}
-		// parse out the continuation id
-		Serializable continuationId;
-		try {
-			continuationId = continuationIdGenerator.parseUid(keyParts[1]);
-		} catch (FlowExecutionRepositoryException e) {
-			throw new BadlyFormattedFlowExecutionKeyException(encodedKey, "The continuation id '" + keyParts[1]
-					+ "' contained in the composite flow execution key '" + encodedKey + "' is invalid", e);
+			throw new BadlyFormattedFlowExecutionKeyException(encodedKey, CompositeFlowExecutionKey.getFormat(), e);
 		}
+		Serializable continuationId = parseContinuationId(keyParts[1], encodedKey);
 		return new CompositeFlowExecutionKey(conversationId, continuationId);
 	}
 
@@ -160,7 +135,7 @@ public abstract class AbstractFlowExecutionRepository implements FlowExecutionRe
 		endConversation(flowExecution);
 	}
 
-	// overridable hooks for use in subclasses
+	// hooks for use in subclasses
 
 	/**
 	 * Factory method that maps a new flow execution to a descriptive
@@ -181,7 +156,9 @@ public abstract class AbstractFlowExecutionRepository implements FlowExecutionRe
 	protected FlowExecutionKey getNextKey(FlowExecution execution) {
 		if (alwaysGenerateNewNextKey) {
 			CompositeFlowExecutionKey key = (CompositeFlowExecutionKey) execution.getKey();
-			return new CompositeFlowExecutionKey(key.getConversationId(), continuationIdGenerator.generateUid());
+			Integer continuationId = (Integer) key.getContinuationId();
+			Integer nextId = Integer.valueOf(continuationId.intValue() + 1);
+			return new CompositeFlowExecutionKey(key.getConversationId(), nextId);
 		} else {
 			return execution.getKey();
 		}
@@ -201,26 +178,48 @@ public abstract class AbstractFlowExecutionRepository implements FlowExecutionRe
 		}
 	}
 
+	/**
+	 * Returns the conversationId portion of the flow execution key.
+	 * @param key the execution key
+	 */
 	protected ConversationId getConversationId(FlowExecutionKey key) {
 		return ((CompositeFlowExecutionKey) key).getConversationId();
 	}
 
+	/**
+	 * Returns the continuationId portion of the flow execution key.
+	 * @param key the execution key
+	 */
 	protected Serializable getContinuationId(FlowExecutionKey key) {
 		return ((CompositeFlowExecutionKey) key).getContinuationId();
 	}
 
+	/**
+	 * Returns the transient state of the flow execution after potential deserialization.
+	 * @param execution the flow execution
+	 * @param key the flow execution key
+	 */
 	protected FlowExecution restoreTransientState(FlowExecution execution, FlowExecutionKey key) {
 		return executionStateRestorer.restoreState(execution, key, getConversationScope(key), this);
 	}
 
+	/**
+	 * Puts the value of conversation scope in the conversation object.
+	 * @param flowExecution the flow execution holding a reference to conversation scope
+	 */
 	protected void putConversationScope(FlowExecution flowExecution) {
 		getConversation(flowExecution.getKey()).putAttribute("scope", flowExecution.getConversationScope());
 	}
 
+	/**
+	 * Assert that a flow execution key has been assigned to the execution.
+	 * @param execution the flow execution
+	 * @throws IllegalStateException if a key has not yet been assigned as expected
+	 */
 	protected void assertKeySet(FlowExecution execution) throws IllegalStateException {
 		if (execution.getKey() == null) {
 			throw new IllegalStateException(
-					"Key for the flow execution is null; make sure the key is assigned first.  Execution = "
+					"The key for the flow execution is null; make sure the key is assigned first.  Execution Details = "
 							+ execution);
 		}
 	}
@@ -233,8 +232,15 @@ public abstract class AbstractFlowExecutionRepository implements FlowExecutionRe
 		return conversation;
 	}
 
+	private Serializable parseContinuationId(String encodedId, String encodedKey) {
+		try {
+			return Integer.valueOf(encodedId);
+		} catch (NumberFormatException e) {
+			throw new BadlyFormattedFlowExecutionKeyException(encodedKey, CompositeFlowExecutionKey.getFormat(), e);
+		}
+	}
+
 	private Conversation endConversation(FlowExecution flowExecution) {
-		// end the governing conversation
 		Conversation conversation = getConversation(flowExecution.getKey());
 		conversation.end();
 		return conversation;

spring-webflow/src/main/java/org/springframework/webflow/execution/repository/support/CompositeFlowExecutionKey.java

@@ -42,14 +42,14 @@ import org.springframework.webflow.execution.repository.continuation.FlowExecuti
 class CompositeFlowExecutionKey extends FlowExecutionKey {
 
 	/**
-	 * The default conversation id prefix delimiter ("_c").
+	 * The default conversation id prefix delimiter.
 	 */
-	private static final String CONVERSATION_ID_PREFIX = "_c";
+	private static final String CONVERSATION_ID_PREFIX = "c";
 
 	/**
-	 * The default continuation id prefix delimiter ("_k").
+	 * The default continuation id prefix delimiter.
 	 */
-	private static final String CONTINUATION_ID_PREFIX = "_k";
+	private static final String CONTINUATION_ID_PREFIX = "v";
 
 	/**
 	 * The format of the default string-encoded form, as returned by toString().
@@ -112,6 +112,13 @@ class CompositeFlowExecutionKey extends FlowExecutionKey {
 
 	// static helpers
 
+	/**
+	 * Returns a string description of the format of this key.
+	 */
+	public static String getFormat() {
+		return FORMAT;
+	}
+
 	/**
 	 * Helper that splits the string-form of an instance of this class into its "parts" so the parts can be easily
 	 * parsed.

spring-webflow/src/main/java/org/springframework/webflow/mvc/AjaxHandler.java

@@ -0,0 +1,27 @@
+package org.springframework.webflow.mvc;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+/**
+ * Strategy interface that encapsulates knowledge about a client-side ajax system and how to communicate with that
+ * system.
+ * @author Keith Donald
+ */
+public interface AjaxHandler {
+
+	/**
+	 * Is the request from the client an Ajax request?
+	 * @param request the current request
+	 */
+	public boolean isAjaxRequest(HttpServletRequest request);
+
+	/**
+	 * Send a redirect request to the Ajax client. This should cause the client to send a new request to the specified
+	 * target url.
+	 * @param response the response object
+	 * @param targetUrl the target url to redirect to
+	 * @param popup wheter the redirect should be sent from a new popup dialog window
+	 */
+	public void sendAjaxRedirect(HttpServletResponse response, String targetUrl, boolean popup);
+}

spring-webflow/src/main/java/org/springframework/webflow/mvc/FlowController.java

@@ -9,7 +9,6 @@ import javax.servlet.http.HttpServletResponse;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.springframework.util.StringUtils;
 import org.springframework.web.servlet.ModelAndView;
 import org.springframework.web.servlet.mvc.AbstractController;
 import org.springframework.webflow.context.servlet.DefaultFlowUrlHandler;
@@ -29,32 +28,14 @@ import org.springframework.webflow.executor.FlowExecutor;
  */
 public class FlowController extends AbstractController {
 
-	/**
-	 * The response header to be set on an Ajax redirect
-	 */
-	private static final String FLOW_REDIRECT_URL_HEADER = "Flow-Redirect-URL";
-
-	/**
-	 * The response header to be set on an redirect that should be issued from a popup window.
-	 */
-	private static final String POPUP_VIEW_HEADER = "Flow-Modal-View";
-
-	/**
-	 * The accept header value that signifies an Ajax request.
-	 */
-	private static final String AJAX_ACCEPT_CONTENT_TYPE = "text/html;type=ajax";
-
-	/**
-	 * Alternate request parameter to indicate an Ajax request for cases when control of the header is not available.
-	 */
-	private static final String AJAX_SOURCE_PARAM = "ajaxSource";
-
 	private static final Log logger = LogFactory.getLog(FlowController.class);
 
 	private FlowExecutor flowExecutor;
 
 	private FlowUrlHandler urlHandler;
 
+	private AjaxHandler ajaxHandler;
+
 	private Map flowHandlers = new HashMap();
 
 	/**
@@ -63,6 +44,7 @@ public class FlowController extends AbstractController {
 	public FlowController(FlowExecutor flowExecutor) {
 		this.flowExecutor = flowExecutor;
 		this.urlHandler = new DefaultFlowUrlHandler();
+		this.ajaxHandler = new SpringJavascriptAjaxHandler();
 		// set the cache seconds property to 0 so no pages are cached by default for flows
 		setCacheSeconds(0);
 	}
@@ -108,20 +90,10 @@ public class FlowController extends AbstractController {
 	protected ServletExternalContext createServletExternalContext(HttpServletRequest request,
 			HttpServletResponse response) {
 		ServletExternalContext context = new ServletExternalContext(getServletContext(), request, response, urlHandler);
-		context.setAjaxRequest(isAjaxRequest(request));
+		context.setAjaxRequest(ajaxHandler.isAjaxRequest(request));
 		return context;
 	}
 
-	protected boolean isAjaxRequest(HttpServletRequest request) {
-		String acceptHeader = request.getHeader("Accept");
-		String ajaxParam = request.getParameter(AJAX_SOURCE_PARAM);
-		if (AJAX_ACCEPT_CONTENT_TYPE.equals(acceptHeader) || StringUtils.hasText(ajaxParam)) {
-			return true;
-		} else {
-			return false;
-		}
-	}
-
 	protected MutableAttributeMap defaultFlowExecutionInputMap(HttpServletRequest request) {
 		return new LocalAttributeMap(request.getParameterMap());
 	}
@@ -200,10 +172,7 @@ public class FlowController extends AbstractController {
 	private void sendRedirect(ServletExternalContext context, HttpServletResponse response, String targetUrl)
 			throws IOException {
 		if (context.isAjaxRequest()) {
-			if (context.redirectInPopup()) {
-				response.setHeader(POPUP_VIEW_HEADER, "true");
-			}
-			response.setHeader(FLOW_REDIRECT_URL_HEADER, response.encodeRedirectURL(targetUrl));
+			ajaxHandler.sendAjaxRedirect(response, targetUrl, context.redirectInPopup());
 		} else {
 			response.sendRedirect(response.encodeRedirectURL(targetUrl));
 		}

spring-webflow/src/main/java/org/springframework/webflow/mvc/FlowHandlerAdapter.java

@@ -7,7 +7,6 @@ import javax.servlet.http.HttpServletResponse;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.springframework.util.StringUtils;
 import org.springframework.web.context.support.WebApplicationObjectSupport;
 import org.springframework.web.servlet.HandlerAdapter;
 import org.springframework.web.servlet.ModelAndView;
@@ -22,43 +21,43 @@ import org.springframework.webflow.execution.repository.NoSuchFlowExecutionExcep
 import org.springframework.webflow.executor.FlowExecutionResult;
 import org.springframework.webflow.executor.FlowExecutor;
 
+/**
+ * A Spring MVC handler adapter that encapsulates the generic workflow associated with executing flows. Delegates to
+ * mapped flow handlers to manage the specific execution semantics required for particular registered flow definition.
+ * 
+ * @author Keith Donald
+ */
 public class FlowHandlerAdapter extends WebApplicationObjectSupport implements HandlerAdapter {
 
-	/**
-	 * The response header to be set on an Ajax redirect
-	 */
-	private static final String FLOW_REDIRECT_URL_HEADER = "Flow-Redirect-URL";
-
-	/**
-	 * The response header to be set on an redirect that should be issued from a popup window.
-	 */
-	private static final String POPUP_VIEW_HEADER = "Flow-Modal-View";
-
-	/**
-	 * The accept header value that signifies an Ajax request.
-	 */
-	private static final String AJAX_ACCEPT_CONTENT_TYPE = "text/html;type=ajax";
-
-	/**
-	 * Alternate request parameter to indicate an Ajax request for cases when control of the header is not available.
-	 */
-	private static final String AJAX_SOURCE_PARAM = "ajaxSource";
-
 	private static final Log logger = LogFactory.getLog(FlowHandlerAdapter.class);
 
 	private FlowExecutor flowExecutor;
 
 	private FlowUrlHandler urlHandler;
 
+	private AjaxHandler ajaxHandler;
+
+	/**
+	 * Creates a new flow handler adapter
+	 * @param flowExecutor the flow executor
+	 */
 	public FlowHandlerAdapter(FlowExecutor flowExecutor) {
 		this.flowExecutor = flowExecutor;
 		this.urlHandler = new DefaultFlowUrlHandler();
+		this.ajaxHandler = new SpringJavascriptAjaxHandler();
 	}
 
+	/**
+	 * Returns the flow url handler.
+	 */
 	public FlowUrlHandler getFlowUrlHandler() {
 		return urlHandler;
 	}
 
+	/**
+	 * Sets the flow url handler
+	 * @param urlHandler the flow url handler
+	 */
 	public void setFlowUrlHandler(FlowUrlHandler urlHandler) {
 		this.urlHandler = urlHandler;
 	}
@@ -96,20 +95,10 @@ public class FlowHandlerAdapter extends WebApplicationObjectSupport implements H
 	protected ServletExternalContext createServletExternalContext(HttpServletRequest request,
 			HttpServletResponse response) {
 		ServletExternalContext context = new ServletExternalContext(getServletContext(), request, response, urlHandler);
-		context.setAjaxRequest(isAjaxRequest(request));
+		context.setAjaxRequest(ajaxHandler.isAjaxRequest(request));
 		return context;
 	}
 
-	protected boolean isAjaxRequest(HttpServletRequest request) {
-		String acceptHeader = request.getHeader("Accept");
-		String ajaxParam = request.getParameter(AJAX_SOURCE_PARAM);
-		if (AJAX_ACCEPT_CONTENT_TYPE.equals(acceptHeader) || StringUtils.hasText(ajaxParam)) {
-			return true;
-		} else {
-			return false;
-		}
-	}
-
 	protected MutableAttributeMap defaultFlowExecutionInputMap(HttpServletRequest request) {
 		return new LocalAttributeMap(request.getParameterMap());
 	}
@@ -189,10 +178,7 @@ public class FlowHandlerAdapter extends WebApplicationObjectSupport implements H
 	private void sendRedirect(ServletExternalContext context, HttpServletResponse response, String targetUrl)
 			throws IOException {
 		if (context.isAjaxRequest()) {
-			if (context.redirectInPopup()) {
-				response.setHeader(POPUP_VIEW_HEADER, "true");
-			}
-			response.setHeader(FLOW_REDIRECT_URL_HEADER, response.encodeRedirectURL(targetUrl));
+			ajaxHandler.sendAjaxRedirect(response, targetUrl, context.redirectInPopup());
 		} else {
 			response.sendRedirect(response.encodeRedirectURL(targetUrl));
 		}

spring-webflow/src/main/java/org/springframework/webflow/mvc/SpringJavascriptAjaxHandler.java

@@ -0,0 +1,53 @@
+package org.springframework.webflow.mvc;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.springframework.util.StringUtils;
+
+/**
+ * Ajax handler that works with Spring Javascript (Spring.js).
+ * 
+ * @author Jeremy Grelle
+ * @author Keith Donald
+ */
+public class SpringJavascriptAjaxHandler implements AjaxHandler {
+
+	/**
+	 * The response header to be set on an Ajax redirect
+	 */
+	private static final String FLOW_REDIRECT_URL_HEADER = "Flow-Redirect-URL";
+
+	/**
+	 * The response header to be set on an redirect that should be issued from a popup window.
+	 */
+	private static final String POPUP_VIEW_HEADER = "Flow-Modal-View";
+
+	/**
+	 * The accept header value that signifies an Ajax request.
+	 */
+	private static final String AJAX_ACCEPT_CONTENT_TYPE = "text/html;type=ajax";
+
+	/**
+	 * Alternate request parameter to indicate an Ajax request for cases when control of the header is not available.
+	 */
+	private static final String AJAX_SOURCE_PARAM = "ajaxSource";
+
+	public boolean isAjaxRequest(HttpServletRequest request) {
+		String acceptHeader = request.getHeader("Accept");
+		String ajaxParam = request.getParameter(AJAX_SOURCE_PARAM);
+		if (AJAX_ACCEPT_CONTENT_TYPE.equals(acceptHeader) || StringUtils.hasText(ajaxParam)) {
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	public void sendAjaxRedirect(HttpServletResponse response, String targetUrl, boolean popup) {
+		if (popup) {
+			response.setHeader(POPUP_VIEW_HEADER, "true");
+		}
+		response.setHeader(FLOW_REDIRECT_URL_HEADER, response.encodeRedirectURL(targetUrl));
+	}
+
+}

spring-webflow/src/test/java/org/springframework/webflow/execution/repository/impl/DefaultFlowExecutionRepositoryTests.java

@@ -53,31 +53,42 @@ public class DefaultFlowExecutionRepositoryTests extends TestCase {
 	}
 
 	public void testParseFlowExecutionKey() {
-		String key = "_c12345_k54321";
+		String key = "c12345v54321";
 		FlowExecutionKey k = repository.parseFlowExecutionKey(key);
 		assertEquals(key, k.toString());
 	}
 
 	public void testParseBadlyFormattedFlowExecutionKey() {
-		String key = "_c12345";
+		String key = "c12345";
 		try {
 			repository.parseFlowExecutionKey(key);
 			fail("Should have failed");
 		} catch (BadlyFormattedFlowExecutionKeyException e) {
-			assertEquals("_c12345", e.getInvalidKey());
+			assertEquals("c12345", e.getInvalidKey());
+			assertNotNull(e.getFormat());
+		}
+	}
+
+	public void testParseBadlyFormattedFlowExecutionKeyBadContinuationId() {
+		String key = "c12345vaaaa";
+		try {
+			repository.parseFlowExecutionKey(key);
+			fail("Should have failed");
+		} catch (BadlyFormattedFlowExecutionKeyException e) {
+			assertEquals("c12345vaaaa", e.getInvalidKey());
 			assertNotNull(e.getFormat());
 		}
 	}
 
 	public void testGetLock() {
-		FlowExecutionKey key = repository.parseFlowExecutionKey("_c12345_k54321");
+		FlowExecutionKey key = repository.parseFlowExecutionKey("c12345v54321");
 		FlowExecutionLock lock = repository.getLock(key);
 		assertNotNull(lock);
 		lock.unlock();
 	}
 
 	public void testGetLockNoSuchFlowExecution() {
-		FlowExecutionKey key = repository.parseFlowExecutionKey("_cbogus_k54321");
+		FlowExecutionKey key = repository.parseFlowExecutionKey("cbogusv54321");
 		try {
 			repository.getLock(key);
 			fail("should have failed");
@@ -93,7 +104,9 @@ public class DefaultFlowExecutionRepositoryTests extends TestCase {
 		execution.start(null, new MockExternalContext());
 		assertNotNull(execution.getKey());
 		repository.putFlowExecution(execution);
-		FlowExecution execution2 = repository.getFlowExecution(execution.getKey());
+		String key = execution.getKey().toString();
+		FlowExecutionKey parsedKey = repository.parseFlowExecutionKey(key);
+		FlowExecution execution2 = repository.getFlowExecution(parsedKey);
 		assertSame(execution.getDefinition(), execution2.getDefinition());
 		assertEquals(execution.getActiveSession().getState().getId(), execution2.getActiveSession().getState().getId());
 	}

spring-webflow/src/test/java/org/springframework/webflow/execution/repository/support/CompositeFlowExecutionKeyTests.java

@@ -22,8 +22,8 @@ import org.springframework.webflow.conversation.impl.SimpleConversationId;
 public class CompositeFlowExecutionKeyTests extends TestCase {
 
 	public void testToString() {
-		CompositeFlowExecutionKey key = new CompositeFlowExecutionKey(new SimpleConversationId("foo"), "bar");
-		assertEquals("_cfoo_kbar", key.toString());
+		CompositeFlowExecutionKey key = new CompositeFlowExecutionKey(new SimpleConversationId("1"), "1");
+		assertEquals("c1v1", key.toString());
 	}
 
 	public void testEquals() {