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1   /*
2    * Copyright 2002-2006 The Apache Software Foundation.
3    *
4    * Licensed under the Apache License, Version 2.0 (the "License");
5    * you may not use this file except in compliance with the License.
6    * You may obtain a copy of the License at
7    *
8    *      http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS,
12   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13   * See the License for the specific language governing permissions and
14   * limitations under the License.
15   */
16  
17  package org.apache.commons.jexl;
18  
19  import org.apache.commons.jexl.context.HashMapContext;
20  
21  /***
22   *  Helper to create a context.  In the current implementation of JEXL, there
23   *  is one implementation of JexlContext - {@link HashMapContext}, and there
24   *  is no reason not to directly instantiate {@link HashMapContext} in your
25   *  own application.
26   *
27   *  @since 1.0
28   *  @author <a href="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
29   *  @version $Id: JexlHelper.java 397092 2006-04-26 05:11:28Z dion $
30   */
31  public class JexlHelper {
32      /*** singleton instance. */
33      protected static JexlHelper helper = new JexlHelper();
34  
35      /*** @return the single instance. */
36      protected static JexlHelper getInstance() {
37          return helper;
38      }
39  
40      /***
41       * Returns a new {@link JexlContext}.
42       * @return a new JexlContext
43       */
44      public static JexlContext createContext() {
45          return getInstance().newContext();
46      }
47  
48      /***
49       * Creates and returns a new {@link JexlContext}.  
50       * The current implementation creates a new instance of 
51       * {@link HashMapContext}.
52       * @return a new JexlContext
53       */
54      protected JexlContext newContext() {
55          return new HashMapContext();
56      }
57  }