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1   /*
2    * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/NumberFunction.java,v 1.11 2005/04/03 01:16:45 elharo Exp $
3    * $Revision: 1.11 $
4    * $Date: 2005/04/03 01:16:45 $
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: NumberFunction.java,v 1.11 2005/04/03 01:16:45 elharo Exp $
60   */
61  
62  package org.jaxen.function;
63  
64  import java.util.Iterator;
65  import java.util.List;
66  
67  import org.jaxen.Context;
68  import org.jaxen.Function;
69  import org.jaxen.FunctionCallException;
70  import org.jaxen.Navigator;
71  
72  /***
73   * <p><b>4.4</b> <code><i>number</i> number(<i>object</i>)</code> 
74   * 
75   * @author bob mcwhirter (bob @ werken.com)
76   */
77  public class NumberFunction implements Function
78    {
79    private final static Double NaN = new Double( Double.NaN );
80      
81    public Object call(Context context, List args) throws FunctionCallException
82      {
83      if (args.size() == 1)
84        {
85        return evaluate( args.get(0), context.getNavigator() );
86        }
87  
88      throw new FunctionCallException( "number() requires one argument." );
89      }
90  
91    public static Double evaluate(Object obj, Navigator nav)
92      {
93      if( obj instanceof Double )
94        {
95        return (Double) obj;
96        }
97      else if (obj instanceof Number)
98        {
99        return new Double( ((Number) obj).doubleValue() );            
100       }
101     else if ( obj instanceof Boolean )
102       {
103       if ( obj == Boolean.TRUE )
104         {
105         return new Double( 1 );
106         }
107       else
108         {
109         return new Double( 0 );
110         }
111       }
112     else if ( obj instanceof String )
113       {
114       String str = (String) obj;
115       
116       try
117         {
118         Double doubleValue = new Double( str );        
119         return doubleValue;
120         }
121       catch (NumberFormatException e)
122         {
123         return new Double( Double.NaN );
124         }
125       }
126     else if ( obj instanceof List || obj instanceof Iterator )
127       {
128       return evaluate( StringFunction.evaluate( obj, nav ), nav );
129       }
130     else if ( nav.isElement( obj ) || nav.isAttribute( obj ) )
131       {
132       return evaluate( StringFunction.evaluate( obj, nav ), nav );
133       }
134     
135     return new Double( Double.NaN );
136     }
137   
138   public static boolean isNaN( double val )
139     {
140     return Double.isNaN(val);
141     }
142   
143   public static boolean isNaN( Double val )
144     {
145     return val.equals( NaN );
146     }    
147   }