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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   * A while loop. Syntax: while ( expression ) statement
24   * 
25   * @author Dion Gillard
26   * @since 1.1
27   */
28  public class ASTWhileStatement extends SimpleNode {
29      /***
30       * Create the node given an id.
31       * 
32       * @param id node id.
33       */
34      public ASTWhileStatement(int id) {
35          super(id);
36      }
37  
38      /***
39       * Create a node with the given parser and id.
40       * 
41       * @param p a parser.
42       * @param id node id.
43       */
44      public ASTWhileStatement(Parser p, int id) {
45          super(p, id);
46      }
47  
48      /*** {@inheritDoc} */
49      public Object jjtAccept(ParserVisitor visitor, Object data) {
50          return visitor.visit(this, data);
51      }
52  
53      /*** {@inheritDoc} */
54      public Object value(JexlContext jc) throws Exception {
55          Object result = null;
56          /* first child is the expression */
57          SimpleNode expressionNode = (SimpleNode) jjtGetChild(0);
58          while (Coercion.coerceBoolean(expressionNode.value(jc)).booleanValue()) {
59              // execute statement
60              result = ((SimpleNode) jjtGetChild(1)).value(jc);
61          }
62  
63          return result;
64      }
65  }