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.runtime.parser.ParserVisitor;
26 import org.apache.velocity.util.TemplateNumber;
27
28 /**
29 * Handles number division of nodes<br><br>
30 *
31 * Please look at the Parser.jjt file which is
32 * what controls the generation of this class.
33 *
34 * @author <a href="mailto:wglass@forio.com">Will Glass-Husain</a>
35 * @author <a href="mailto:pero@antaramusic.de">Peter Romianowski</a>
36 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
37 * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
38 * @version $Id: ASTDivNode.java 463298 2006-10-12 16:10:32Z henning $
39 */
40 public class ASTDivNode extends SimpleNode
41 {
42 /**
43 * @param id
44 */
45 public ASTDivNode(int id)
46 {
47 super(id);
48 }
49
50 /**
51 * @param p
52 * @param id
53 */
54 public ASTDivNode(Parser p, int id)
55 {
56 super(p, id);
57 }
58
59 /**
60 * @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.ParserVisitor, java.lang.Object)
61 */
62 public Object jjtAccept(ParserVisitor visitor, Object data)
63 {
64 return visitor.visit(this, data);
65 }
66
67 /**
68 * computes the result of the division.
69 * @param context
70 * @return result or null
71 * @throws MethodInvocationException
72 */
73 public Object value( InternalContextAdapter context)
74 throws MethodInvocationException
75 {
76 /*
77 * get the two args
78 */
79
80 Object left = jjtGetChild(0).value( context );
81 Object right = jjtGetChild(1).value( context );
82
83 /*
84 * if either is null, lets log and bail
85 */
86
87 if (left == null || right == null)
88 {
89 log.error((left == null ? "Left" : "Right")
90 + " side ("
91 + jjtGetChild( (left == null? 0 : 1) ).literal()
92 + ") of division operation has null value."
93 + " Operation not possible. "
94 + context.getCurrentTemplateName()
95 + " [line " + getLine()
96 + ", column " + getColumn() + "]");
97 return null;
98 }
99
100 /*
101 * convert to Number if applicable
102 */
103 if (left instanceof TemplateNumber)
104 {
105 left = ( (TemplateNumber) left).getAsNumber();
106 }
107 if (right instanceof TemplateNumber)
108 {
109 right = ( (TemplateNumber) right).getAsNumber();
110 }
111
112 /*
113 * if not a Number, not much we can do either
114 */
115 if ( !( left instanceof Number ) || !( right instanceof Number ))
116 {
117 log.error((!(left instanceof Number) ? "Left" : "Right")
118 + " side of division operation is not a number. "
119 + context.getCurrentTemplateName() + " [line " + getLine()
120 + ", column " + getColumn() + "]");
121
122 return null;
123 }
124
125 /*
126 * check for divide by 0
127 */
128 if ( MathUtils.isZero ( (Number)right ) )
129 {
130 log.error("Right side of division operation is zero. Must be non-zero. "
131 + context.getCurrentTemplateName() + " [line " + getLine()
132 + ", column " + getColumn() + "]");
133
134 return null;
135 }
136
137 return MathUtils.divide( (Number)left, (Number)right );
138 }
139 }