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