1/*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the  "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
9 *
10 *     http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18/*
19 * $Id: Minus.java 468655 2006-10-28 07:12:06Z minchau $
20 */
21package org.apache.xpath.operations;
22
23import org.apache.xpath.XPathContext;
24import org.apache.xpath.objects.XNumber;
25import org.apache.xpath.objects.XObject;
26
27/**
28 * The binary '-' operation expression executer.
29 */
30public class Minus extends Operation
31{
32    static final long serialVersionUID = -5297672838170871043L;
33
34  /**
35   * Apply the operation to two operands, and return the result.
36   *
37   *
38   * @param left non-null reference to the evaluated left operand.
39   * @param right non-null reference to the evaluated right operand.
40   *
41   * @return non-null reference to the XObject that represents the
42   *         result of the operation.
43   *
44   * @throws javax.xml.transform.TransformerException
45   */
46  public XObject operate(XObject left, XObject right)
47          throws javax.xml.transform.TransformerException
48  {
49    return new XNumber(left.num() - right.num());
50  }
51
52  /**
53   * Evaluate this operation directly to a double.
54   *
55   * @param xctxt The runtime execution context.
56   *
57   * @return The result of the operation as a double.
58   *
59   * @throws javax.xml.transform.TransformerException
60   */
61  public double num(XPathContext xctxt)
62          throws javax.xml.transform.TransformerException
63  {
64
65    return (m_left.num(xctxt) - m_right.num(xctxt));
66  }
67
68}
69