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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  import org.apache.velocity.util.TemplateNumber;
26  
27  /**
28   * Handles multiplication<br><br>
29   *
30   * Please look at the Parser.jjt file which is
31   * what controls the generation of this class.
32   *
33   * @author <a href="mailto:wglass@forio.com">Will Glass-Husain</a>
34   * @author <a href="mailto:pero@antaramusic.de">Peter Romianowski</a>
35   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
36   * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
37   * @version $Id: ASTMulNode.java 517553 2007-03-13 06:09:58Z wglass $
38   */
39  public class ASTMulNode extends SimpleNode
40  {
41      /**
42       * @param id
43       */
44      public ASTMulNode(int id)
45      {
46          super(id);
47      }
48  
49      /**
50       * @param p
51       * @param id
52       */
53      public ASTMulNode(Parser p, int id)
54      {
55          super(p, id);
56      }
57  
58      /**
59       * @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.node.ParserVisitor, java.lang.Object)
60       */
61      public Object jjtAccept(ParserVisitor visitor, Object data)
62      {
63          return visitor.visit(this, data);
64      }
65  
66      /**
67       *  computes the product of the two args.
68       * @param context
69       *  @return result or null
70       * @throws MethodInvocationException
71       */
72      public Object value( InternalContextAdapter context )
73          throws MethodInvocationException
74      {
75          /*
76           *  get the two args
77           */
78  
79          Object left = jjtGetChild(0).value( context );
80          Object right = jjtGetChild(1).value( context );
81  
82          /*
83           *  if either is null, lets log and bail
84           */
85  
86          if (left == null || right == null)
87          {
88              log.error((left == null ? "Left" : "Right")
89                             + " side ("
90                             + jjtGetChild( (left == null? 0 : 1) ).literal()
91                             + ") of multiplication operation has null value."
92                             + " Operation not possible. "
93                             + context.getCurrentTemplateName() + " [line " + getLine()
94                             + ", column " + getColumn() + "]");
95              return null;
96          }
97  
98          /*
99           *  convert to Number if applicable
100          */
101         if (left instanceof TemplateNumber)
102         {
103            left = ( (TemplateNumber) left).getAsNumber();
104         }
105         if (right instanceof TemplateNumber)
106         {
107            right = ( (TemplateNumber) right).getAsNumber();
108         }
109 
110         /*
111          *  if not a Number, not much we can do either
112          */
113 
114         if ( !( left instanceof Number )  || !( right instanceof Number ))
115         {
116             log.error((!(left instanceof Number) ? "Left" : "Right")
117                            + " side of multiplication operation is not a Number. "
118                            +  context.getCurrentTemplateName() + " [line " + getLine()
119                            + ", column " + getColumn() + "]");
120 
121             return null;
122         }
123 
124         return MathUtils.multiply( (Number)left, (Number)right);
125     }
126 }
127 
128 
129 
130