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 number addition of nodes.<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:jvanzyl@apache.org">Jason van Zyl</a>
31 * @author <a href="mailto:geirm@optonline.net">Geir Magnusson Jr.</a>
32 * @version $Id: ASTAddNode.java 463298 2006-10-12 16:10:32Z henning $
33 */
34 import org.apache.velocity.context.InternalContextAdapter;
35 import org.apache.velocity.runtime.parser.Parser;
36 import org.apache.velocity.runtime.parser.ParserVisitor;
37
38 import org.apache.velocity.exception.MethodInvocationException;
39
40 import org.apache.velocity.util.TemplateNumber;
41
42 /**
43 *
44 */
45 public class ASTAddNode extends SimpleNode
46 {
47 /**
48 * @param id
49 */
50 public ASTAddNode(int id)
51 {
52 super(id);
53 }
54
55 /**
56 * @param p
57 * @param id
58 */
59 public ASTAddNode(Parser p, int id)
60 {
61 super(p, id);
62 }
63
64 /**
65 * @see org.apache.velocity.runtime.parser.node.SimpleNode#jjtAccept(org.apache.velocity.runtime.parser.ParserVisitor, java.lang.Object)
66 */
67 public Object jjtAccept(ParserVisitor visitor, Object data)
68 {
69 return visitor.visit(this, data);
70 }
71
72 /**
73 * computes the sum of the two nodes.
74 * @param context
75 * @return result or null
76 * @throws MethodInvocationException
77 */
78 public Object value( InternalContextAdapter context)
79 throws MethodInvocationException
80 {
81 /*
82 * get the two addends
83 */
84
85 Object left = jjtGetChild(0).value(context);
86 Object right = jjtGetChild(1).value(context);
87
88 /*
89 * if either is null, lets log and bail
90 */
91
92 if (left == null || right == null)
93 {
94 log.error((left == null ? "Left" : "Right")
95 + " side ("
96 + jjtGetChild( (left == null? 0 : 1) ).literal()
97 + ") of addition operation has null value."
98 + " Operation not possible. "
99 + context.getCurrentTemplateName() + " [line " + getLine()
100 + ", column " + getColumn() + "]");
101 return null;
102 }
103
104 /*
105 * convert to Number if applicable
106 */
107 if (left instanceof TemplateNumber)
108 {
109 left = ( (TemplateNumber) left).getAsNumber();
110 }
111 if (right instanceof TemplateNumber)
112 {
113 right = ( (TemplateNumber) right).getAsNumber();
114 }
115
116 /*
117 * Arithmetic operation.
118 */
119 if (left instanceof Number && right instanceof Number)
120 {
121 return MathUtils.add((Number)left, (Number)right);
122 }
123
124 /*
125 * shall we try for strings?
126 */
127 if (left instanceof String || right instanceof String)
128 {
129 return left.toString().concat(right.toString());
130 }
131 /*
132 * if not a Number or Strings, not much we can do right now
133 */
134 log.error((!(left instanceof Number || left instanceof String) ? "Left" : "Right")
135 + " side of addition operation is not a valid type. "
136 + "Currently only Strings, numbers (1,2,3...) and Number type are supported. "
137 + context.getCurrentTemplateName() + " [line " + getLine()
138 + ", column " + getColumn() + "]");
139
140 return null;
141 }
142 }
143
144
145
146