2009/05/20 - Apache Shale has been retired.

 /*

  * 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.shale.view.impl;

 import java.util.HashSet;

 import java.util.Set;

 import org.apache.shale.view.ViewControllerMapper;

 /**

  * <p>{@link DefaultViewControllerMapper} is a default implementation of {@link ViewControllerMapper}.  The following

  * algorithm is implemented:</p>

  * <ul>

  * <li>Strip any leading slash ("/") character.</li>

  * <li>Strip any traling extension (".xxx"), as long as it occurs

  *     after any remaining slash ("/") character.</li>

  * <li>Convert each instance of a slash ("/")

  *     character into a dollar sign ("$") character.</li>

  * <li>If the resulting name matches one of the reserved names recognized

  *     by the default <code>VariableResolver</code>, prefix it with an

  *     underscore character ("_"), to avoid problems loading managed beans.</li>

  * <li>If the resulting name starts with a digit character, prefix it with

  *     an underscore character("_"), to avoid problems evaluating value

  *     binding expressions using it (because this would be treated as a

  *     variable name starting with a digit, and that is not allowed by the

  *     syntax of expression evaluation).</li>

  * </ul>

  *

  * <p>Examples of correct managed bean names for typical JSF view identifiers,

  * when this mapper is used, would include:</p>

  * <ul>

  * <li>For a view identifier <code>/mainmenu.jsp</code>, your managed bean

  *     name <em>must</em> be <code>mainmenu</code> (leading slash and

  *     trailing extension were stripped).</li>

  * <li>For a view identifier <code>/customer/details.jsp</code>, your managed

  *     bean name <em>must</em> be <code>customer$details</code> (intermediate

  *     slash character also converted).</li>

  * <li>For a view identifier <code>/header.jsp</code>, your managed bean

  *     name <em>must</em> be <code>_header</code> ("header" is a magic JSF

  *     variable returning a Map of HTTP headers for the current request, so

  *     you cannot use this name for your own managed beans).</li>

  * </ul>

  *

  *

  * <p>Since the managed bean names also need to be valid variable names in

  * the expression language, this mapper implementation imposes certain

  * restrictions on the view identifiers. View identifiers must not contain

  * characters which have reserved meanings in the expression language, such

  * as '-' (minus) or '+' (plus). A best practice while using this mapper

  * is to ensure view identifiers use letters of the English alphabet

  * in upper or lower case, digits from 0 to 9, '$' (dollar signs) and '_'

  * (underscores) only.</p>

  *

  * $Id: DefaultViewControllerMapper.java 464373 2006-10-16 04:21:54Z rahul $

  */

 public class DefaultViewControllerMapper implements ViewControllerMapper {

     // -------------------------------------------------------- Static Variables

     /**

      * <p>Reserved variable names.</p>

      */

     private static Set reserved = new HashSet();

     static {

         reserved.add("applicationScope");

         reserved.add("cookie");

         reserved.add("facesContext");

         reserved.add("header");

         reserved.add("headerValues");

         reserved.add("initParam");

         reserved.add("param");

         reserved.add("paramValues");

         reserved.add("requestScope");

         reserved.add("sessionScope");

         reserved.add("view");

     }

     // ---------------------------------------------------------- Public Methods

     /** {@inheritDoc} */

     public String mapViewId(String viewId) {

         if (viewId == null) {

             return null;

         }

         if (viewId.startsWith("/")) {

             viewId = viewId.substring(1);

         }

         int slash = viewId.lastIndexOf("/");

         int period = viewId.lastIndexOf(".");

         if ((period >= 0) && (period > slash)) {

             viewId = viewId.substring(0, period);

         }

         viewId = viewId.replace('/', '$');

         if (reserved.contains(viewId)) {

             return "_" + viewId;

         } else if ((viewId.length() > 0) && Character.isDigit(viewId.charAt(0))) {

             return "_" + viewId;

         } else {

             return viewId;

         }

     }

 }