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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultMinusExpr.java,v 1.9 2003/09/05 04:08:48 proyal Exp $
3    * $Revision: 1.9 $
4    * $Date: 2003/09/05 04:08:48 $
5    *
6    * ====================================================================
7    *
8    * Copyright (C) 2000-2002 bob mcwhirter & James Strachan.
9    * All rights reserved.
10   *
11   * Redistribution and use in source and binary forms, with or without
12   * modification, are permitted provided that the following conditions
13   * are met:
14   *
15   * 1. Redistributions of source code must retain the above copyright
16   *    notice, this list of conditions, and the following disclaimer.
17   *
18   * 2. Redistributions in binary form must reproduce the above copyright
19   *    notice, this list of conditions, and the disclaimer that follows
20   *    these conditions in the documentation and/or other materials
21   *    provided with the distribution.
22   *
23   * 3. The name "Jaxen" must not be used to endorse or promote products
24   *    derived from this software without prior written permission.  For
25   *    written permission, please contact license@jaxen.org.
26   *
27   * 4. Products derived from this software may not be called "Jaxen", nor
28   *    may "Jaxen" appear in their name, without prior written permission
29   *    from the Jaxen Project Management (pm@jaxen.org).
30   *
31   * In addition, we request (but do not require) that you include in the
32   * end-user documentation provided with the redistribution and/or in the
33   * software itself an acknowledgement equivalent to the following:
34   *     "This product includes software developed by the
35   *      Jaxen Project (http://www.jaxen.org/)."
36   * Alternatively, the acknowledgment may be graphical using the logos
37   * available at http://www.jaxen.org/
38   *
39   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
40   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
41   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
42   * DISCLAIMED.  IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT
43   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
44   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
45   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
46   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
47   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
48   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
49   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50   * SUCH DAMAGE.
51   *
52   * ====================================================================
53   * This software consists of voluntary contributions made by many
54   * individuals on behalf of the Jaxen Project and was originally
55   * created by bob mcwhirter <bob@werken.com> and
56   * James Strachan <jstrachan@apache.org>.  For more information on the
57   * Jaxen Project, please see <http://www.jaxen.org/>.
58   *
59   * $Id: DefaultMinusExpr.java,v 1.9 2003/09/05 04:08:48 proyal Exp $
60   */
61  
62  
63  package org.jaxen.expr;
64  
65  import org.jaxen.Context;
66  import org.jaxen.JaxenException;
67  import org.jaxen.function.NumberFunction;
68  
69  class DefaultMinusExpr extends DefaultAdditiveExpr
70  {
71      public DefaultMinusExpr(Expr lhs,
72                              Expr rhs)
73      {
74          super( lhs,
75                 rhs );
76      }
77  
78      public String getOperator()
79      {
80          return "-";
81      }
82  
83      public Object evaluate(Context context) throws JaxenException
84      {
85          Number lhsValue = NumberFunction.evaluate( getLHS().evaluate( context ),
86                                                     context.getNavigator() );
87          Number rhsValue = NumberFunction.evaluate( getRHS().evaluate( context ),
88                                                     context.getNavigator() );
89  
90          double result = lhsValue.doubleValue() - rhsValue.doubleValue();
91          return new Double( result );
92      }
93  
94      public void accept(Visitor visitor)
95      {
96          visitor.visit(this);
97      }
98  }