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1   package org.apache.velocity.runtime.parser.node;
2   
3   /*
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *   http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.    
20   */
21  
22  import org.apache.velocity.runtime.parser.Parser;
23  import org.apache.velocity.runtime.parser.ParserVisitor;
24  import org.apache.velocity.context.InternalContextAdapter;
25  
26  import org.apache.velocity.exception.MethodInvocationException;
27  
28  /**
29   * Please look at the Parser.jjt file which is
30   * what controls the generation of this class.
31   *
32   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
33   * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
34   * @version $Id: ASTOrNode.java 463298 2006-10-12 16:10:32Z henning $
35  */
36  public class ASTOrNode extends SimpleNode
37  {
38      /**
39       * @param id
40       */
41      public ASTOrNode(int id)
42      {
43          super(id);
44      }
45  
46      /**
47       * @param p
48       * @param id
49       */
50      public ASTOrNode(Parser p, int id)
51      {
52          super(p, id);
53      }
54  
55      /**
56       * @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.ParserVisitor, java.lang.Object)
57       */
58      public Object jjtAccept(ParserVisitor visitor, Object data)
59      {
60          return visitor.visit(this, data);
61      }
62  
63      /**
64       *  Returns the value of the expression.
65       *  Since the value of the expression is simply the boolean
66       *  result of evaluate(), lets return that.
67       * @param context
68       * @return The Expression value.
69       * @throws MethodInvocationException
70       */
71      public Object value(InternalContextAdapter context )
72          throws MethodInvocationException
73      {
74          // TODO: JDK 1.4+ -> valueOf()
75          return new Boolean(evaluate(context));
76      }
77  
78      /**
79       *  the logical or :
80       *    the rule :
81       *      left || null -> left
82       *      null || right -> right
83       *      null || null -> false
84       *      left || right ->  left || right
85       * @param context
86       * @return The evaluation result.
87       * @throws MethodInvocationException
88       */
89      public boolean evaluate( InternalContextAdapter context)
90          throws MethodInvocationException
91      {
92          Node left = jjtGetChild(0);
93          Node right = jjtGetChild(1);
94  
95          /*
96           *  if the left is not null and true, then true
97           */
98  
99          if (left != null && left.evaluate( context ) )
100             return true;
101 
102         /*
103          *  same for right
104          */
105 
106         if ( right != null && right.evaluate( context ) )
107             return true;
108 
109         return false;
110     }
111 }
112 
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116