/*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you under the Apache License, Version 2.0 (the
    * "License"); you may not use this file except in compliance
    * with the License.  You may obtain a copy of the License at
    *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package org.apache.myfaces.application;
  
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Comparator;
  import java.util.EnumSet;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Map;
  import java.util.Set;
  import java.util.logging.Level;
  import java.util.logging.Logger;
  
  import java.util.regex.Pattern;
  import javax.faces.FacesException;
  import javax.faces.application.ConfigurableNavigationHandler;
  import javax.faces.application.FacesMessage;
  import javax.faces.application.NavigationCase;
  import javax.faces.application.ProjectStage;
  import javax.faces.application.ViewHandler;
  import javax.faces.component.UIComponent;
  import javax.faces.component.UIViewRoot;
  import javax.faces.component.visit.VisitCallback;
  import javax.faces.component.visit.VisitContext;
  import javax.faces.component.visit.VisitHint;
  import javax.faces.component.visit.VisitResult;
  import javax.faces.context.ExternalContext;
  import javax.faces.context.FacesContext;
  import javax.faces.context.PartialViewContext;
  import javax.faces.view.ViewDeclarationLanguage;
  import javax.faces.view.ViewMetadata;
  
  import org.apache.myfaces.config.RuntimeConfig;
  import org.apache.myfaces.config.element.NavigationRule;
  import org.apache.myfaces.shared.application.NavigationUtils;
  import org.apache.myfaces.shared.renderkit.html.util.SharedStringBuilder;
  import org.apache.myfaces.shared.util.HashMapUtils;
  import org.apache.myfaces.shared.util.StringUtils;
  import org.apache.myfaces.view.facelets.tag.jsf.PreDisposeViewEvent;
  
  /**
   * @author Thomas Spiegl (latest modification by $Author: lu4242 $)
   * @author Anton Koinov
   * @version $Revision: 1669632 $ $Date: 2015-03-27 17:49:47 +0000 (Fri, 27 Mar 2015) $
   */
  public class NavigationHandlerImpl
      extends ConfigurableNavigationHandler
  {
      //private static final Log log = LogFactory.getLog(NavigationHandlerImpl.class);
      private static final Logger log = Logger.getLogger(NavigationHandlerImpl.class.getName());
  
      private static final String SKIP_ITERATION_HINT = "javax.faces.visit.SKIP_ITERATION";
      
      private static final Set<VisitHint> VISIT_HINTS = Collections.unmodifiableSet(
              EnumSet.of(VisitHint.SKIP_ITERATION));    
      
      private static final String OUTCOME_NAVIGATION_SB = "oam.navigation.OUTCOME_NAVIGATION_SB";
      
      private static final Pattern AMP_PATTERN = Pattern.compile("&(amp;)?"); // "&" or "&amp;"
      
      private static final String ASTERISK = "*";
  
      private Map<String, Set<NavigationCase>> _navigationCases = null;
      private List<String> _wildcardKeys = new ArrayList<String>();
      private Boolean _developmentStage;
      
      private NavigationHandlerSupport navigationHandlerSupport;
  
      public NavigationHandlerImpl()
      {
          if (log.isLoggable(Level.FINEST))
          {
              log.finest("New NavigationHandler instance created");
          }
      }
  
      @Override
      public void handleNavigation(FacesContext facesContext, String fromAction, String outcome)
     {
         NavigationCase navigationCase = getNavigationCase(facesContext, fromAction, outcome);
 
         if (navigationCase != null)
         {
             if (log.isLoggable(Level.FINEST))
             {
                 log.finest("handleNavigation fromAction=" + fromAction + " outcome=" + outcome +
                           " toViewId =" + navigationCase.getToViewId(facesContext) +
                           " redirect=" + navigationCase.isRedirect());
             }
             if (navigationCase.isRedirect())
             { 
                 //&& (!PortletUtil.isPortletRequest(facesContext)))
                 // Spec section 7.4.2 says "redirects not possible" in this case for portlets
                 //But since the introduction of portlet bridge and the 
                 //removal of portlet code in myfaces core 2.0, this condition
                 //no longer applies
                 
                 ExternalContext externalContext = facesContext.getExternalContext();
                 ViewHandler viewHandler = facesContext.getApplication().getViewHandler();
                 String toViewId = navigationCase.getToViewId(facesContext);
                 
 
                 String redirectPath = viewHandler.getRedirectURL(
                         facesContext, toViewId, 
                         NavigationUtils.getEvaluatedNavigationParameters(facesContext,
                         navigationCase.getParameters()) ,
                         navigationCase.isIncludeViewParams());
                 
                 //Clear ViewMap if we are redirecting to other resource
                 UIViewRoot viewRoot = facesContext.getViewRoot(); 
                 if (viewRoot != null && !toViewId.equals(viewRoot.getViewId()))
                 {
                     //call getViewMap(false) to prevent unnecessary map creation
                     Map<String, Object> viewMap = viewRoot.getViewMap(false);
                     if (viewMap != null)
                     {
                         viewMap.clear();
                     }
                 }
                 
                 // JSF 2.0 the javadoc of handleNavigation() says something like this 
                 // "...If the view has changed after an application action, call
                 // PartialViewContext.setRenderAll(true)...". The effect is that ajax requests
                 // are included on navigation.
                 PartialViewContext partialViewContext = facesContext.getPartialViewContext();
                 String viewId = facesContext.getViewRoot() != null ? facesContext.getViewRoot().getViewId() : null;
                 if ( partialViewContext.isPartialRequest() && 
                      !partialViewContext.isRenderAll() && 
                      toViewId != null &&
                      !toViewId.equals(viewId))
                 {
                     partialViewContext.setRenderAll(true);
                 }
                 
                 // JSF 2.0 Spec call Flash.setRedirect(true) to notify Flash scope and take proper actions
                 externalContext.getFlash().setRedirect(true);
                 try
                 {
                     externalContext.redirect(redirectPath);
                     facesContext.responseComplete();
                 }
                 catch (IOException e)
                 {
                     throw new FacesException(e.getMessage(), e);
                 }
             }
             else
             {
                 ViewHandler viewHandler = facesContext.getApplication().getViewHandler();
                 //create new view
                 String newViewId = navigationCase.getToViewId(facesContext);
                 // JSF 2.0 the javadoc of handleNavigation() says something like this 
                 // "...If the view has changed after an application action, call
                 // PartialViewContext.setRenderAll(true)...". The effect is that ajax requests
                 // are included on navigation.
                 PartialViewContext partialViewContext = facesContext.getPartialViewContext();
                 String viewId = facesContext.getViewRoot() != null ? facesContext.getViewRoot().getViewId() : null;
                 if ( partialViewContext.isPartialRequest() && 
                      !partialViewContext.isRenderAll() && 
                      newViewId != null &&
                      !newViewId.equals(viewId))
                 {
                     partialViewContext.setRenderAll(true);
                 }
 
                 if (facesContext.getViewRoot() != null &&
                     facesContext.getViewRoot().getAttributes().containsKey("oam.CALL_PRE_DISPOSE_VIEW"))
                 {
                     try
                     {
                         facesContext.getAttributes().put(SKIP_ITERATION_HINT, Boolean.TRUE);
 
                         VisitContext visitContext = VisitContext.createVisitContext(facesContext, null, VISIT_HINTS);
                         facesContext.getViewRoot().visitTree(visitContext,
                                                              new PreDisposeViewCallback());
                     }
                     finally
                     {
                         facesContext.getAttributes().remove(SKIP_ITERATION_HINT);
                     }
                 }
 
                 // create UIViewRoot for new view
                 UIViewRoot viewRoot = null;
                 
                 String derivedViewId = viewHandler.deriveViewId(facesContext, newViewId);
 
                 if (derivedViewId != null)
                 {
                     ViewDeclarationLanguage vdl = viewHandler.getViewDeclarationLanguage(facesContext, derivedViewId);
                     
                     if (vdl != null)
                     {
                         ViewMetadata metadata = vdl.getViewMetadata(facesContext, newViewId);
                         
                         if (metadata != null)
                         {
                             viewRoot = metadata.createMetadataView(facesContext);
                         }
                     }
                 }
                 
                 // viewRoot can be null here, if ...
                 //   - we don't have a ViewDeclarationLanguage (e.g. when using facelets-1.x)
                 //   - there is no view metadata or metadata.createMetadataView() returned null
                 //   - viewHandler.deriveViewId() returned null
                 if (viewRoot == null)
                 {
                     viewRoot = viewHandler.createView(facesContext, newViewId);
                 }
                 
                 facesContext.setViewRoot(viewRoot);
                 facesContext.renderResponse();
             }
         }
         else
         {
             // no navigationcase found, stay on current ViewRoot
             if (log.isLoggable(Level.FINEST))
             {
                 log.finest("handleNavigation fromAction=" + fromAction + " outcome=" + outcome +
                           " no matching navigation-case found, staying on current ViewRoot");
             }
         }
     }
 
     /**
     * @return the navigationHandlerSupport
     */
     protected NavigationHandlerSupport getNavigationHandlerSupport()
     {
         if (navigationHandlerSupport == null)
         {
             navigationHandlerSupport = new DefaultNavigationHandlerSupport();
         }
         return navigationHandlerSupport;
     }
 
     public void setNavigationHandlerSupport(NavigationHandlerSupport navigationHandlerSupport)
     {
         this.navigationHandlerSupport = navigationHandlerSupport;
     }
 
     private static class PreDisposeViewCallback implements VisitCallback
     {
 
         public VisitResult visit(VisitContext context, UIComponent target)
         {
             context.getFacesContext().getApplication().publishEvent(context.getFacesContext(),
                                                                     PreDisposeViewEvent.class, target);
             
             return VisitResult.ACCEPT;
         }
     }
 
     /**
      * Returns the navigation case that applies for the given action and outcome
      */
     public NavigationCase getNavigationCase(FacesContext facesContext, String fromAction, String outcome)
     {
         String viewId = facesContext.getViewRoot() != null ? facesContext.getViewRoot().getViewId() : null;
         
         Map<String, Set<NavigationCase>> casesMap = getNavigationCases();
         NavigationCase navigationCase = null;
         
         Set<? extends NavigationCase> casesSet;
         if (viewId != null)
         {
             casesSet = casesMap.get(viewId);
             if (casesSet != null)
             {
                 // Exact match?
                 navigationCase = calcMatchingNavigationCase(facesContext, casesSet, fromAction, outcome);
             }
         }
 
         if (navigationCase == null)
         {
             // Wildcard match?
             List<String> sortedWildcardKeys = getSortedWildcardKeys();
             for (int i = 0; i < sortedWildcardKeys.size(); i++)
             {
                 String fromViewId = sortedWildcardKeys.get(i);
                 if (fromViewId.length() > 2)
                 {
                     String prefix = fromViewId.substring(0, fromViewId.length() - 1);
                     if (viewId != null && viewId.startsWith(prefix))
                     {
                         casesSet = casesMap.get(fromViewId);
                         if (casesSet != null)
                         {
                             navigationCase = calcMatchingNavigationCase(facesContext, casesSet, fromAction, outcome);
                             if (navigationCase != null)
                             {
                                 break;
                             }
                         }
                     }
                 }
                 else
                 {
                     casesSet = casesMap.get(fromViewId);
                     if (casesSet != null)
                     {
                         navigationCase = calcMatchingNavigationCase(facesContext, casesSet, fromAction, outcome);
                         if (navigationCase != null)
                         {
                             break;
                         }
                     }
                 }
             }
         }
         
         if (outcome != null && navigationCase == null)
         {
             //if outcome is null, we don't check outcome based nav cases
             //otherwise, if navgiationCase is still null, check outcome-based nav cases
             navigationCase = getOutcomeNavigationCase (facesContext, fromAction, outcome);
         }
         
         if (outcome != null && navigationCase == null && !facesContext.isProjectStage(ProjectStage.Production))
         {
             final FacesMessage facesMessage = new FacesMessage("No navigation case match for viewId " + viewId + 
                     ",  action " + fromAction + " and outcome " + outcome);
             facesMessage.setSeverity(FacesMessage.SEVERITY_WARN);
             facesContext.addMessage(null, facesMessage);
         }
 
         return navigationCase;  //if navigationCase == null, will stay on current view
 
     }
     
     /**
      * Performs the algorithm specified in 7.4.2 for situations where no navigation cases are defined and instead
      * the navigation case is to be determined from the outcome.
      * 
      * TODO: cache results?
      */
     private NavigationCase getOutcomeNavigationCase (FacesContext facesContext, String fromAction, String outcome)
     {
         String implicitViewId = null;
         boolean includeViewParams = false;
         int index;
         boolean isRedirect = false;
         String queryString = null;
         NavigationCase result = null;
         String viewId = facesContext.getViewRoot() != null ? facesContext.getViewRoot().getViewId() : null;
         //String viewIdToTest = outcome;
         StringBuilder viewIdToTest = SharedStringBuilder.get(facesContext, OUTCOME_NAVIGATION_SB);
         viewIdToTest.append(outcome);
         
         // If viewIdToTest contains a query string, remove it and set queryString with that value.
         index = viewIdToTest.indexOf ("?");
         if (index != -1)
         {
             queryString = viewIdToTest.substring (index + 1);
             //viewIdToTest = viewIdToTest.substring (0, index);
             viewIdToTest.setLength(index);
             
             // If queryString contains "faces-redirect=true", set isRedirect to true.
             if (queryString.indexOf ("faces-redirect=true") != -1)
             {
                 isRedirect = true;
             }
             
             // If queryString contains "includeViewParams=true" or 
             // "faces-include-view-params=true", set includeViewParams to true.
             if (queryString.indexOf("includeViewParams=true") != -1 
                     || queryString.indexOf("faces-include-view-params=true") != -1)
             {
                 includeViewParams = true;
             }
         }
         
         // If viewIdToTest does not have a "file extension", use the one from the current viewId.
         index = viewIdToTest.indexOf (".");
         if (index == -1)
         {
             if (viewId != null)
             {
                 index = viewId.lastIndexOf(".");
 
                 if (index != -1)
                 {
                     //viewIdToTest += viewId.substring (index);
                     viewIdToTest.append(viewId.substring (index));
                 }
             }
             else
             {
                 // This case happens when for for example there is a ViewExpiredException,
                 // and a custom ExceptionHandler try to navigate using implicit navigation.
                 // In this case, there is no UIViewRoot set on the FacesContext, so viewId 
                 // is null.
 
                 // In this case, it should try to derive the viewId of the view that was
                 // not able to restore, to get the extension and apply it to
                 // the implicit navigation.
                 String tempViewId = getNavigationHandlerSupport().calculateViewId(facesContext);
                 if (tempViewId != null)
                 {
                     index = tempViewId.lastIndexOf(".");
                     if(index != -1)
                     {
                         viewIdToTest.append(tempViewId.substring (index));
                     }
                 }
             }
             if (log.isLoggable(Level.FINEST))
             {
                 log.finest("getOutcomeNavigationCase -> viewIdToTest: " + viewIdToTest);
             } 
         }
 
         // If viewIdToTest does not start with "/", look for the last "/" in viewId.  If not found, simply prepend "/".
         // Otherwise, prepend everything before and including the last "/" in viewId.
         
         //if (!viewIdToTest.startsWith ("/") && viewId != null)
         boolean startWithSlash = false;
         if (viewIdToTest.length() > 0)
         {
             startWithSlash = (viewIdToTest.charAt(0) == '/');
         } 
         if (!startWithSlash) 
         {
             index = -1;
             if( viewId != null )
             {
                index = viewId.lastIndexOf ("/");
             }
             
             if (index == -1)
             {
                 //viewIdToTest = "/" + viewIdToTest;
                 viewIdToTest.insert(0,"/");
             }
             
             else
             {
                 //viewIdToTest = viewId.substring (0, index + 1) + viewIdToTest;
                 viewIdToTest.insert(0, viewId, 0, index + 1);
             }
         }
         
         // Call ViewHandler.deriveViewId() and set the result as implicitViewId.
         
         try
         {
             implicitViewId = facesContext.getApplication().getViewHandler().deriveViewId (
                     facesContext, viewIdToTest.toString());
         }
         
         catch (UnsupportedOperationException e)
         {
             // This is the case when a pre-JSF 2.0 ViewHandler is used.
             // In this case, the default algorithm must be used.
             // FIXME: I think we're always calling the "default" ViewHandler.deriveViewId() algorithm and we don't
             // distinguish between pre-JSF 2.0 and JSF 2.0 ViewHandlers.  This probably needs to be addressed.
         }
         
         if (implicitViewId != null)
         {
             // Append all params from the queryString
             // (excluding faces-redirect, includeViewParams and faces-include-view-params)
             Map<String, List<String>> params = null;
             if (queryString != null && !"".equals(queryString))
             {
                 //String[] splitQueryParams = queryString.split("&(amp;)?"); // "&" or "&amp;"
                 String[] splitQueryParams = AMP_PATTERN.split(queryString); // "&" or "&amp;"
                 params = new HashMap<String, List<String>>(splitQueryParams.length, 
                         (splitQueryParams.length* 4 + 3) / 3);
                 for (String queryParam : splitQueryParams)
                 {
                     String[] splitParam = StringUtils.splitShortString(queryParam, '=');
                     if (splitParam.length == 2)
                     {
                         // valid parameter - add it to params
                         if ("includeViewParams".equals(splitParam[0])
                                 || "faces-include-view-params".equals(splitParam[0])
                                 || "faces-redirect".equals(splitParam[0]))
                         {
                             // ignore includeViewParams, faces-include-view-params and faces-redirect
                             continue;
                         }
                         List<String> paramValues = params.get(splitParam[0]);
                         if (paramValues == null)
                         {
                             // no value for the given parameter yet
                             paramValues = new ArrayList<String>();
                             params.put(splitParam[0], paramValues);
                         }
                         paramValues.add(splitParam[1]);
                     }
                     else
                     {
                         // invalid parameter
                         throw new FacesException("Invalid parameter \"" + 
                                 queryParam + "\" in outcome " + outcome);
                     }
                 }
             }
             
             // Finally, create the NavigationCase.
             result = new NavigationCase (viewId, fromAction, outcome, null, 
                     implicitViewId, params, isRedirect, includeViewParams);
         }
         
         return result;
     }
     
     /**
      * Returns the view ID that would be created for the given action and outcome
      */
     public String getViewId(FacesContext context, String fromAction, String outcome)
     {
         return this.getNavigationCase(context, fromAction, outcome).getToViewId(context);
     }
 
     /**
      * TODO
      * Invoked by the navigation handler before the new view component is created.
      * @param viewId The view ID to be created
      * @return The view ID that should be used instead. If null, the view ID passed
      * in will be used without modification.
      */
     public String beforeNavigation(String viewId)
     {
         return null;
     }
 
     private NavigationCase calcMatchingNavigationCase(FacesContext context,
                                                       Set<? extends NavigationCase> casesList,
                                                       String actionRef,
                                                       String outcome)
     {
         NavigationCase noConditionCase = null;
         NavigationCase firstCase = null;
         NavigationCase firstCaseIf = null;
         NavigationCase secondCase = null;
         NavigationCase secondCaseIf = null;
         NavigationCase thirdCase = null;
         NavigationCase thirdCaseIf = null;
         NavigationCase fourthCase = null;
         NavigationCase fourthCaseIf = null;
                         
         for (NavigationCase caze : casesList)
         {
             String cazeOutcome = caze.getFromOutcome();
             String cazeActionRef = caze.getFromAction();
             Boolean cazeIf = caze.getCondition(context);
             boolean ifMatches = (cazeIf == null ? false : cazeIf.booleanValue());
             // JSF 2.0: support conditional navigation via <if>.
             // Use for later cases.
             
             if(outcome == null && (cazeOutcome != null || cazeIf == null) && actionRef == null)
             {
                 //To match an outcome value of null, the <from-outcome> must be absent and the <if> element present.
                 continue;
             }
             
             //If there are no conditions on navigation case save it and return as last resort
             if (cazeOutcome == null && cazeActionRef == null &&
                 cazeIf == null && noConditionCase == null && outcome != null)
             {
                 noConditionCase = caze;
             }
             
             if (cazeActionRef != null)
             {
                 if (cazeOutcome != null)
                 {
                     if ((actionRef != null) && (outcome != null) && cazeActionRef.equals (actionRef) &&
                             cazeOutcome.equals (outcome))
                     {
                         // First case: match if <from-action> matches action and <from-outcome> matches outcome.
                         // Caveat: evaluate <if> if available.
 
                         if (cazeIf != null)
                         {
                             if (ifMatches)
                             {
                                 firstCaseIf = caze;
                                 //return caze;
                             }
 
                             continue;
                         }
                         else
                         {
                             firstCase = caze;
                             //return caze;
                         }
                     }
                 }
                 else
                 {
                     if ((actionRef != null) && cazeActionRef.equals (actionRef))
                     {
                         // Third case: if only <from-action> specified, match against action.
                         // Caveat: if <if> is available, evaluate.  If not, only match if outcome is not null.
 
                         if (cazeIf != null)
                         {
                             if (ifMatches)
                             {
                                 thirdCaseIf = caze;
                                 //return caze;
                             }
                             
                             continue;
                         }
                         else
                         {
                             if (outcome != null)
                             {
                                 thirdCase = caze;
                                 //return caze;
                             }
                             
                             continue;
                         }
                     }
                     else
                     {
                         // cazeActionRef != null and cazeOutcome == null
                         // but cazeActionRef does not match. No additional operation
                         // required because cazeIf is only taken into account 
                         // it cazeActionRef match. 
                         continue;
                     }
                 }
             }
             else
             {
                 if (cazeOutcome != null)
                 {
                     if ((outcome != null) && cazeOutcome.equals (outcome))
                     {
                         // Second case: if only <from-outcome> specified, match against outcome.
                         // Caveat: if <if> is available, evaluate.
 
                         if (cazeIf != null)
                         {
                             if (ifMatches)
                             {
                                 secondCaseIf = caze;
                                 //return caze;
                             }
                             
                             continue;
                         }
                         else
                         {
                             secondCase = caze;
                             //return caze;
                         }
                     }
                 }
             }
 
             // Fourth case: anything else matches if outcome is not null or <if> is specified.
 
             if (outcome != null)
             {
                 // Again, if <if> present, evaluate.
                 if (cazeIf != null)
                 {
                     if (ifMatches)
                     {
                         fourthCaseIf = caze;
                         //return caze;
                     }
                     
                     continue;
                 }
             }
 
             if ((cazeIf != null) && ifMatches)
             {
                 fourthCase = caze;
                 //return caze;
             }
         }
         
         if (firstCaseIf != null)
         {
             return firstCaseIf;
         }
         else if (firstCase != null)
         {
             return firstCase;
         }
         else if (secondCaseIf != null)
         {
             return secondCaseIf;
         }
         else if (secondCase != null)
         {
             return secondCase;
         }
         else if (thirdCaseIf != null)
         {
             return thirdCaseIf;
         }
         else if (thirdCase != null)
         {
             return thirdCase;
         }
         else if (fourthCaseIf != null)
         {
             return fourthCaseIf;
         }
         else if (fourthCase != null)
         {
             return fourthCase;
         }
         
         return noConditionCase;
     }
 
     private List<String> getSortedWildcardKeys()
     {
         return _wildcardKeys;
     }
 
     @Override
     public Map<String, Set<NavigationCase>> getNavigationCases()
     {
         if (_developmentStage == null)
         {
             _developmentStage = FacesContext.getCurrentInstance().isProjectStage(ProjectStage.Development);
         }
         if (!Boolean.TRUE.equals(_developmentStage))
         {
             if (_navigationCases == null)
             {
                 FacesContext facesContext = FacesContext.getCurrentInstance();
                 ExternalContext externalContext = facesContext.getExternalContext();
                 RuntimeConfig runtimeConfig = RuntimeConfig.getCurrentInstance(externalContext);
                 
                 calculateNavigationCases(facesContext, runtimeConfig);
             }
             return _navigationCases;
         }
         else
         {
             FacesContext facesContext = FacesContext.getCurrentInstance();
             ExternalContext externalContext = facesContext.getExternalContext();
             RuntimeConfig runtimeConfig = RuntimeConfig.getCurrentInstance(externalContext);
 
             if (_navigationCases == null || runtimeConfig.isNavigationRulesChanged())
             {
                 calculateNavigationCases(facesContext, runtimeConfig);
             }
             return _navigationCases;
         }
     }
     
     private synchronized void calculateNavigationCases(FacesContext facesContext, RuntimeConfig runtimeConfig)
     {
         if (_navigationCases == null || runtimeConfig.isNavigationRulesChanged())
         {
             Collection<? extends NavigationRule> rules = runtimeConfig.getNavigationRules();
             int rulesSize = rules.size();
 
             Map<String, Set<NavigationCase>> cases = new HashMap<String, Set<NavigationCase>>(
                     HashMapUtils.calcCapacity(rulesSize));
 
             List<String> wildcardKeys = new ArrayList<String>();
 
             for (NavigationRule rule : rules)
             {
                 String fromViewId = rule.getFromViewId();
 
                 //specification 7.4.2 footnote 4 - missing fromViewId is allowed:
                 if (fromViewId == null)
                 {
                     fromViewId = ASTERISK;
                 }
                 else
                 {
                     fromViewId = fromViewId.trim();
                 }
 
                 Set<NavigationCase> set = cases.get(fromViewId);
                 if (set == null)
                 {
                     set = new HashSet<NavigationCase>(convertNavigationCasesToAPI(rule));
                     cases.put(fromViewId, set);
                     if (fromViewId.endsWith(ASTERISK))
                     {
                         wildcardKeys.add(fromViewId);
                     }
                 }
                 else
                 {
                     set.addAll(convertNavigationCasesToAPI(rule));
                 }
             }
 
             Collections.sort(wildcardKeys, new KeyComparator());
 
             synchronized (cases)
             {
                 // We do not really need this sychronization at all, but this
                 // gives us the peace of mind that some good optimizing compiler
                 // will not rearrange the execution of the assignment to an
                 // earlier time, before all init code completes
                 _navigationCases = cases;
                 _wildcardKeys = wildcardKeys;
 
                 runtimeConfig.setNavigationRulesChanged(false);
             }
         }
     }
 
     private static final class KeyComparator implements Comparator<String>
     {
         public int compare(String s1, String s2)
         {
             return -s1.compareTo(s2);
         }
     }
     
     private Set<NavigationCase> convertNavigationCasesToAPI(NavigationRule rule)
     {
         Collection<? extends org.apache.myfaces.config.element.NavigationCase> configCases = rule.getNavigationCases();
         Set<NavigationCase> apiCases = new HashSet<NavigationCase>(configCases.size());
         
         for(org.apache.myfaces.config.element.NavigationCase configCase : configCases)
         {   
             if(configCase.getRedirect() != null)
             {
                 String includeViewParamsAttribute = configCase.getRedirect().getIncludeViewParams();
                 boolean includeViewParams = false; // default value is false
                 if (includeViewParamsAttribute != null)
                 {
                     includeViewParams = new Boolean(includeViewParamsAttribute);
                 }
                 apiCases.add(new NavigationCase(rule.getFromViewId(),configCase.getFromAction(),
                                                 configCase.getFromOutcome(),configCase.getIf(),configCase.getToViewId(),
                                                 configCase.getRedirect().getViewParams(),true,includeViewParams));
             }
             else
             {
                 apiCases.add(new NavigationCase(rule.getFromViewId(),configCase.getFromAction(),
                                                 configCase.getFromOutcome(),configCase.getIf(),
                                                 configCase.getToViewId(),null,false,false));
             }
         }
         
         return apiCases;
     }
 
 }