001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one
003     * or more contributor license agreements.  See the NOTICE file
004     * distributed with this work for additional information
005     * regarding copyright ownership.  The ASF licenses this file
006     * to you under the Apache License, Version 2.0 (the
007     * "License"); you may not use this file except in compliance
008     * with the License.  You may obtain a copy of the License at
009     *
010     *   http://www.apache.org/licenses/LICENSE-2.0
011     *
012     * Unless required by applicable law or agreed to in writing,
013     * software distributed under the License is distributed on an
014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015     * KIND, either express or implied.  See the License for the
016     * specific language governing permissions and limitations
017     * under the License.
018     */
019    
020    package org.apache.myfaces.tobago.util;
021    
022    import javax.faces.application.Application;
023    import javax.faces.context.FacesContext;
024    import javax.faces.el.VariableResolver;
025    import javax.faces.el.ValueBinding;
026    
027    public class VariableResolverUtil {
028    
029      private VariableResolverUtil() {
030      }
031    
032      public static Object resolveVariable(FacesContext context, String variable) {
033        Application application = context.getApplication();
034        VariableResolver variableResolver = application.getVariableResolver();
035        return variableResolver.resolveVariable(context, variable);
036      }
037    
038      /**
039       * Clears the value of the variable.
040       * Useful for cleaning up e.g. a session or application variable
041       * to save memory without the knowledge of the scope.
042       * Also useful to enforce a new creation of a managed-bean.
043       *
044       * @param context
045       * @param variable
046       */
047      public static void clearVariable(FacesContext context, String variable) {
048        Application application = context.getApplication();
049        ValueBinding valueBinding = application.createValueBinding("#{" + variable + "}");
050        valueBinding.setValue(context, null);
051      }
052    }