01: /*
02: * Copyright 1999-2004 The Apache Software Foundation.
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
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: * $Id: Neg.java,v 1.9 2004/08/17 19:25:40 jycli Exp $
18: */
19: package org.apache.xpath.operations;
20:
21: import org.apache.xpath.XPathContext;
22: import org.apache.xpath.objects.XNumber;
23: import org.apache.xpath.objects.XObject;
24:
25: /**
26: * The unary '-' operation expression executer.
27: */
28: public class Neg extends UnaryOperation {
29: static final long serialVersionUID = -6280607702375702291L;
30:
31: /**
32: * Apply the operation to two operands, and return the result.
33: *
34: *
35: * @param right non-null reference to the evaluated right operand.
36: *
37: * @return non-null reference to the XObject that represents the result of the operation.
38: *
39: * @throws javax.xml.transform.TransformerException
40: */
41: public XObject operate(XObject right)
42: throws javax.xml.transform.TransformerException {
43: return new XNumber(-right.num());
44: }
45:
46: /**
47: * Evaluate this operation directly to a double.
48: *
49: * @param xctxt The runtime execution context.
50: *
51: * @return The result of the operation as a double.
52: *
53: * @throws javax.xml.transform.TransformerException
54: */
55: public double num(XPathContext xctxt)
56: throws javax.xml.transform.TransformerException {
57:
58: return -(m_right.num(xctxt));
59: }
60:
61: }
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