/*

  * 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.shared.application;

 import java.util.ArrayList;

 import java.util.HashMap;

 import java.util.List;

 import java.util.Map;

 import javax.faces.context.FacesContext;

 public class NavigationUtils

 {

     /**

      * Evaluate all EL expressions found as parameters and return a map that can be used for 

      * redirect or render bookmark links

      * 

      * @param parameters parameter map retrieved from NavigationCase.getParameters()

      * @return

      */

     public static Map<String, List<String> > getEvaluatedNavigationParameters(

             FacesContext facesContext, 

             Map<String, List<String> > parameters)

     {

         Map<String,List<String>> evaluatedParameters = null;

         if (parameters != null && parameters.size() > 0)

         {

             evaluatedParameters = new HashMap<String, List<String>>();

             for (Map.Entry<String, List<String>> pair : parameters.entrySet())

             {

                 boolean containsEL = false;

                 for (String value : pair.getValue())

                 {

                     if (_isExpression(value))

                     {

                         containsEL = true;

                         break;

                     }

                 }

                 if (containsEL)

                 {

                     evaluatedParameters.put(pair.getKey(), 

                             _evaluateValueExpressions(facesContext, pair.getValue()));

                 }

                 else

                 {

                     evaluatedParameters.put(pair.getKey(), pair.getValue());

                 }

             }

         }

         else

         {

             evaluatedParameters = parameters;

         }

         return evaluatedParameters;

     }

     /**

      * Checks the Strings in the List for EL expressions and evaluates them.

      * Note that the returned List will be a copy of the given List, because

      * otherwise it will have unwanted side-effects.

      * @param values

      * @return

      */

     private static List<String> _evaluateValueExpressions(FacesContext context, List<String> values)

     {

         // note that we have to create a new List here, because if we

         // change any value on the given List, it will be changed in the

         // NavigationCase too and the EL expression won't be evaluated again

         List<String> target = new ArrayList<String>(values.size());

         for (String value : values)

         {

             if (_isExpression(value))

             {

                 // evaluate the ValueExpression

                 value = context.getApplication().evaluateExpressionGet(context, value, String.class);

             }

             target.add(value);

         }

         return target;

     }

     private static boolean _isExpression(String text)

     {

         return text.indexOf("#{") != -1;

     }

 }