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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.context.InternalContextAdapter;
23  import org.apache.velocity.exception.MethodInvocationException;
24  import org.apache.velocity.runtime.parser.Parser;
25  
26  /**
27   * Please look at the Parser.jjt file which is
28   * what controls the generation of this class.
29   *
30   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
31   * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
32   * @version $Id: ASTOrNode.java 517553 2007-03-13 06:09:58Z wglass $
33  */
34  public class ASTOrNode extends SimpleNode
35  {
36      /**
37       * @param id
38       */
39      public ASTOrNode(int id)
40      {
41          super(id);
42      }
43  
44      /**
45       * @param p
46       * @param id
47       */
48      public ASTOrNode(Parser p, int id)
49      {
50          super(p, id);
51      }
52  
53      /**
54       * @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.node.ParserVisitor, java.lang.Object)
55       */
56      public Object jjtAccept(ParserVisitor visitor, Object data)
57      {
58          return visitor.visit(this, data);
59      }
60  
61      /**
62       *  Returns the value of the expression.
63       *  Since the value of the expression is simply the boolean
64       *  result of evaluate(), lets return that.
65       * @param context
66       * @return The Expression value.
67       * @throws MethodInvocationException
68       */
69      public Object value(InternalContextAdapter context )
70          throws MethodInvocationException
71      {
72          // TODO: JDK 1.4+ -> valueOf()
73          return new Boolean(evaluate(context));
74      }
75  
76      /**
77       *  the logical or :
78       *    the rule :
79       *      left || null -> left
80       *      null || right -> right
81       *      null || null -> false
82       *      left || right ->  left || right
83       * @param context
84       * @return The evaluation result.
85       * @throws MethodInvocationException
86       */
87      public boolean evaluate( InternalContextAdapter context)
88          throws MethodInvocationException
89      {
90          Node left = jjtGetChild(0);
91          Node right = jjtGetChild(1);
92  
93          /*
94           *  if the left is not null and true, then true
95           */
96  
97          if (left != null && left.evaluate( context ) )
98              return true;
99  
100         /*
101          *  same for right
102          */
103 
104         if ( right != null && right.evaluate( context ) )
105             return true;
106 
107         return false;
108     }
109 }
110 
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114