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 /**
23 * Handles modulus division<br><br>
24 *
25 * Please look at the Parser.jjt file which is
26 * what controls the generation of this class.
27 *
28 * @author <a href="mailto:wglass@forio.com">Will Glass-Husain</a>
29 * @author <a href="mailto:pero@antaramusic.de">Peter Romianowski</a>
30 * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
31 * @version $Id: ASTModNode.java 517553 2007-03-13 06:09:58Z wglass $
32 */
33 import org.apache.velocity.context.InternalContextAdapter;
34 import org.apache.velocity.exception.MethodInvocationException;
35 import org.apache.velocity.runtime.parser.Parser;
36 import org.apache.velocity.util.TemplateNumber;
37
38 /**
39 *
40 */
41 public class ASTModNode extends SimpleNode
42 {
43 /**
44 * @param id
45 */
46 public ASTModNode(int id)
47 {
48 super(id);
49 }
50
51 /**
52 * @param p
53 * @param id
54 */
55 public ASTModNode(Parser p, int id)
56 {
57 super(p, id);
58 }
59
60 /**
61 * @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.node.ParserVisitor, java.lang.Object)
62 */
63 public Object jjtAccept(ParserVisitor visitor, Object data)
64 {
65 return visitor.visit(this, data);
66 }
67
68 /**
69 * @see org.apache.velocity.runtime.parser.node.SimpleNode#value(org.apache.velocity.context.InternalContextAdapter)
70 */
71 public Object value( InternalContextAdapter context)
72 throws MethodInvocationException
73 {
74 /*
75 * get the two args
76 */
77
78 Object left = jjtGetChild(0).value( context );
79 Object right = jjtGetChild(1).value( context );
80
81 /*
82 * if either is null, lets log and bail
83 */
84
85 if (left == null || right == null)
86 {
87 log.error((left == null ? "Left" : "Right")
88 + " side ("
89 + jjtGetChild( (left == null? 0 : 1) ).literal()
90 + ") of modulus operation has null value."
91 + " Operation not possible. "
92 + context.getCurrentTemplateName() + " [line " + getLine()
93 + ", column " + getColumn() + "]");
94 return null;
95 }
96
97 /*
98 * convert to Number if applicable
99 */
100 if (left instanceof TemplateNumber)
101 {
102 left = ( (TemplateNumber) left).getAsNumber();
103 }
104 if (right instanceof TemplateNumber)
105 {
106 right = ( (TemplateNumber) right).getAsNumber();
107 }
108
109 /*
110 * Both values must be a number.
111 */
112 if ( ! (left instanceof Number) || ! (right instanceof Number) )
113 {
114
115 log.error((!(left instanceof Number) ? "Left" : "Right")
116 + " side "
117 + " of modulus operation is not a Number. "
118 + context.getCurrentTemplateName() + " [line " + getLine()
119 + ", column " + getColumn() + "]");
120 return null;
121
122 }
123
124 /*
125 * check for divide / modulo by 0
126 */
127 if ( MathUtils.isZero ( (Number) right ) )
128 {
129
130 log.error("Right side of modulus operation is zero. Must be non-zero. "
131 + context.getCurrentTemplateName() + " [line " + getLine()
132 + ", column " + getColumn() + "]");
133 return null;
134
135 }
136
137 return MathUtils.modulo ((Number)left, (Number)right);
138
139 }
140 }
141