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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  }