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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.parser;
18  
19  import org.apache.commons.jexl.JexlContext;
20  import org.apache.commons.jexl.util.Coercion;
21  
22  /***
23   * if ( expression ) statement [else statement].
24   * 
25   * @author Dion Gillard
26   * @since 1.1
27   */
28  public class ASTIfStatement extends SimpleNode {
29      /*** child index of the else statement to execute. */
30      private static final int ELSE_STATEMENT_INDEX = 2;
31      /***
32       * Create the node given an id.
33       * 
34       * @param id node id.
35       */
36      public ASTIfStatement(int id) {
37          super(id);
38      }
39  
40      /***
41       * Create a node with the given parser and id.
42       * 
43       * @param p a parser.
44       * @param id node id.
45       */
46      public ASTIfStatement(Parser p, int id) {
47          super(p, id);
48      }
49  
50      /*** {@inheritDoc} */
51      public Object jjtAccept(ParserVisitor visitor, Object data) {
52          return visitor.visit(this, data);
53      }
54  
55      /*** {@inheritDoc} */
56      public Object value(JexlContext jc) throws Exception {
57          Object result = null;
58          /* first child is the expression */
59          Object expression = ((SimpleNode) jjtGetChild(0)).value(jc);
60          if (Coercion.coerceBoolean(expression).booleanValue()) {
61              // true statement
62              result = ((SimpleNode) jjtGetChild(1)).value(jc);
63          } else {
64              // if there is a false, execute it
65              if (jjtGetNumChildren() == ELSE_STATEMENT_INDEX + 1) {
66                  result = ((SimpleNode) jjtGetChild(2)).value(jc);
67              }
68          }
69  
70          return result;
71      }
72  
73  }