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 517553 2007-03-13 06:09:58Z wglass $
33 */
34 import org.apache.velocity.context.InternalContextAdapter;
35 import org.apache.velocity.exception.MethodInvocationException;
36 import org.apache.velocity.runtime.parser.Parser;
37 import org.apache.velocity.util.TemplateNumber;
38
39 /**
40 *
41 */
42 public class ASTAddNode extends SimpleNode
43 {
44 /**
45 * @param id
46 */
47 public ASTAddNode(int id)
48 {
49 super(id);
50 }
51
52 /**
53 * @param p
54 * @param id
55 */
56 public ASTAddNode(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.node.ParserVisitor, java.lang.Object)
63 */
64 public Object jjtAccept(ParserVisitor visitor, Object data)
65 {
66 return visitor.visit(this, data);
67 }
68
69 /**
70 * computes the sum of the two nodes.
71 * @param context
72 * @return result or null
73 * @throws MethodInvocationException
74 */
75 public Object value( InternalContextAdapter context)
76 throws MethodInvocationException
77 {
78 /*
79 * get the two addends
80 */
81
82 Object left = jjtGetChild(0).value(context);
83 Object right = jjtGetChild(1).value(context);
84
85 /*
86 * if either is null, lets log and bail
87 */
88
89 if (left == null || right == null)
90 {
91 log.error((left == null ? "Left" : "Right")
92 + " side ("
93 + jjtGetChild( (left == null? 0 : 1) ).literal()
94 + ") of addition operation has null value."
95 + " Operation not possible. "
96 + context.getCurrentTemplateName() + " [line " + getLine()
97 + ", column " + getColumn() + "]");
98 return null;
99 }
100
101 /*
102 * convert to Number if applicable
103 */
104 if (left instanceof TemplateNumber)
105 {
106 left = ( (TemplateNumber) left).getAsNumber();
107 }
108 if (right instanceof TemplateNumber)
109 {
110 right = ( (TemplateNumber) right).getAsNumber();
111 }
112
113 /*
114 * Arithmetic operation.
115 */
116 if (left instanceof Number && right instanceof Number)
117 {
118 return MathUtils.add((Number)left, (Number)right);
119 }
120
121 /*
122 * shall we try for strings?
123 */
124 if (left instanceof String || right instanceof String)
125 {
126 return left.toString().concat(right.toString());
127 }
128 /*
129 * if not a Number or Strings, not much we can do right now
130 */
131 log.error((!(left instanceof Number || left instanceof String) ? "Left" : "Right")
132 + " side of addition operation is not a valid type. "
133 + "Currently only Strings, numbers (1,2,3...) and Number type are supported. "
134 + context.getCurrentTemplateName() + " [line " + getLine()
135 + ", column " + getColumn() + "]");
136
137 return null;
138 }
139 }
140
141
142
143