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 463298 2006-10-12 16:10:32Z henning $
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.runtime.parser.ParserVisitor;
37 import org.apache.velocity.util.TemplateNumber;
38
39 /**
40 *
41 */
42 public class ASTModNode extends SimpleNode
43 {
44 /**
45 * @param id
46 */
47 public ASTModNode(int id)
48 {
49 super(id);
50 }
51
52 /**
53 * @param p
54 * @param id
55 */
56 public ASTModNode(Parser p, int id)
57 {
58 super(p, id);
59 }
60
61 /**
62 * @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.ParserVisitor, java.lang.Object)
63 */
64 public Object jjtAccept(ParserVisitor visitor, Object data)
65 {
66 return visitor.visit(this, data);
67 }
68
69 /**
70 * @see org.apache.velocity.runtime.parser.node.SimpleNode#value(org.apache.velocity.context.InternalContextAdapter)
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 modulus 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 * Both values must be a number.
112 */
113 if ( ! (left instanceof Number) || ! (right instanceof Number) )
114 {
115
116 log.error((!(left instanceof Number) ? "Left" : "Right")
117 + " side "
118 + " of modulus operation is not a Number. "
119 + context.getCurrentTemplateName() + " [line " + getLine()
120 + ", column " + getColumn() + "]");
121 return null;
122
123 }
124
125 /*
126 * check for divide / modulo by 0
127 */
128 if ( MathUtils.isZero ( (Number) right ) )
129 {
130
131 log.error("Right side of modulus operation is zero. Must be non-zero. "
132 + context.getCurrentTemplateName() + " [line " + getLine()
133 + ", column " + getColumn() + "]");
134 return null;
135
136 }
137
138 return MathUtils.modulo ((Number)left, (Number)right);
139
140 }
141 }
142