KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > org > apache > commons > jexl > parser > ASTSubtractNode


1 /*
2  * Copyright 2002-2006 The Apache Software Foundation.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 package org.apache.commons.jexl.parser;
18
19 import org.apache.commons.jexl.util.Coercion;
20 import org.apache.commons.jexl.JexlContext;
21
22 /**
23  * Subtraction.
24  *
25  * @author <a HREF="mailto:geirm@apache.org">Geir Magnusson Jr.</a>
26  * @author <a HREF="mailto:mhw@kremvax.net">Mark H. Wilkinson</a>
27  * @version $Id: ASTSubtractNode.java 398325 2006-04-30 12:34:29Z dion $
28  */
29 public class ASTSubtractNode extends SimpleNode {
30     /**
31      * Create the node given an id.
32      *
33      * @param id node id.
34      */
35     public ASTSubtractNode(int id) {
36         super(id);
37     }
38
39     /**
40      * Create a node with the given parser and id.
41      *
42      * @param p a parser.
43      * @param id node id.
44      */
45     public ASTSubtractNode(Parser p, int id) {
46         super(p, id);
47     }
48
49     /** {@inheritDoc} */
50     public Object JavaDoc value(JexlContext context) throws Exception JavaDoc {
51         Object JavaDoc left = ((SimpleNode) jjtGetChild(0)).value(context);
52         Object JavaDoc right = ((SimpleNode) jjtGetChild(1)).value(context);
53
54         /*
55          * the spec says 'and', I think 'or'
56          */
57         if (left == null && right == null) {
58             return new Byte JavaDoc((byte) 0);
59         }
60
61         /*
62          * if anything is float, double or string with ( "." | "E" | "e") coerce
63          * all to doubles and do it
64          */
65         if (left instanceof Float JavaDoc
66             || left instanceof Double JavaDoc
67             || right instanceof Float JavaDoc
68             || right instanceof Double JavaDoc
69             || (left instanceof String JavaDoc
70                 && (((String JavaDoc) left).indexOf(".") != -1
71                     || ((String JavaDoc) left).indexOf("e") != -1
72                     || ((String JavaDoc) left).indexOf("E") != -1))
73             || (right instanceof String JavaDoc
74                 && (((String JavaDoc) right).indexOf(".") != -1
75                     || ((String JavaDoc) right).indexOf("e") != -1
76                     || ((String JavaDoc) right).indexOf("E") != -1))) {
77             Double JavaDoc l = Coercion.coerceDouble(left);
78             Double JavaDoc r = Coercion.coerceDouble(right);
79
80             return new Double JavaDoc(l.doubleValue() - r.doubleValue());
81         }
82
83         /*
84          * otherwise to longs with thee!
85          */
86
87         Long JavaDoc l = Coercion.coerceLong(left);
88         Long JavaDoc r = Coercion.coerceLong(right);
89
90         return new Long JavaDoc(l.longValue() - r.longValue());
91
92     }
93
94     /** {@inheritDoc} */
95     public Object JavaDoc jjtAccept(ParserVisitor visitor, Object JavaDoc data) {
96         return visitor.visit(this, data);
97     }
98 }
99
Popular Tags