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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/expr/DefaultUnaryExpr.java,v 1.11 2005/03/21 22:39:16 elharo Exp $
3    * $Revision: 1.11 $
4    * $Date: 2005/03/21 22:39:16 $
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: DefaultUnaryExpr.java,v 1.11 2005/03/21 22:39:16 elharo Exp $
60   */
61  
62  
63  
64  package org.jaxen.expr;
65  
66  import org.jaxen.Context;
67  import org.jaxen.JaxenException;
68  import org.jaxen.function.NumberFunction;
69  
70  class DefaultUnaryExpr extends DefaultExpr implements UnaryExpr
71  {
72      private Expr expr;
73  
74      public DefaultUnaryExpr(Expr expr)
75      {
76          this.expr = expr;
77      }
78  
79      public Expr getExpr()
80      {
81          return this.expr;
82      }
83  
84      public String toString()
85      {
86          return "[(DefaultUnaryExpr): " + getExpr() + "]";
87      }
88  
89      public String getText()
90      {
91          return "-(" + getExpr().getText() + ")";
92      }
93  
94      public Expr simplify()
95      {
96          expr = expr.simplify();
97  
98          return this;
99      }
100 
101     public Object evaluate(Context context) throws JaxenException
102     {
103         Number number = NumberFunction.evaluate( getExpr().evaluate( context ),
104                                                  context.getNavigator() );
105 
106         return new Double( number.doubleValue() * -1 );
107     }
108     public void accept(Visitor visitor)
109     {
110         visitor.visit(this);
111     }
112 }