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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  
20  package org.apache.myfaces.tobago.util;
21  
22  import org.apache.myfaces.tobago.context.ClientProperties;
23  
24  import javax.el.ELContext;
25  import javax.faces.context.FacesContext;
26  
27  public final class VariableResolverUtils {
28  
29    private VariableResolverUtils() {
30      // utils class
31    }
32  
33    /**
34     * Returns the requested object configured in the faces-config or from library.
35     */
36    public static Object resolveVariable(FacesContext context, String variable) {
37      final ELContext elContext = context.getELContext();
38      return elContext.getELResolver().getValue(elContext, null, variable);
39    }
40  
41    /**
42     * Returns the ClientProperties object configured in the faces-config.
43     */
44    public static ClientProperties resolveClientProperties(FacesContext facesContext) {
45      return (ClientProperties) resolveVariable(facesContext, ClientProperties.MANAGED_BEAN_NAME);
46    }
47    
48    /**
49     * Clears the value of the variable.
50     * Useful for cleaning up e.g. a session or application variable
51     * to save memory without the knowledge of the scope.
52     * Also useful to enforce a new creation of a managed-bean.
53     */
54    public static void clearVariable(FacesContext context, String variable) {
55      final ELContext elContext = context.getELContext();
56      elContext.getELResolver().setValue(elContext, null, variable, null);
57    }
58  }