Coverage Report - org.jaxen.function.NumberFunction
 
Classes in this File Line Coverage Branch Coverage Complexity
NumberFunction
100%
26/26
100%
8/8
4.8
 
 1  
 /*
 2  
  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/NumberFunction.java,v 1.18 2006/02/05 21:47:41 elharo Exp $
 3  
  * $Revision: 1.18 $
 4  
  * $Date: 2006/02/05 21:47:41 $
 5  
  *
 6  
  * ====================================================================
 7  
  *
 8  
  * Copyright 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 are
 13  
  * met:
 14  
  * 
 15  
  *   * Redistributions of source code must retain the above copyright
 16  
  *     notice, this list of conditions and the following disclaimer.
 17  
  * 
 18  
  *   * Redistributions in binary form must reproduce the above copyright
 19  
  *     notice, this list of conditions and the following disclaimer in the
 20  
  *     documentation and/or other materials provided with the distribution.
 21  
  * 
 22  
  *   * Neither the name of the Jaxen Project nor the names of its
 23  
  *     contributors may be used to endorse or promote products derived 
 24  
  *     from this software without specific prior written permission.
 25  
  * 
 26  
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 27  
  * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 28  
  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 29  
  * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
 30  
  * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 31  
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 32  
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 33  
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 34  
  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 35  
  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 36  
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 37  
  *
 38  
  * ====================================================================
 39  
  * This software consists of voluntary contributions made by many 
 40  
  * individuals on behalf of the Jaxen Project and was originally 
 41  
  * created by bob mcwhirter <bob@werken.com> and 
 42  
  * James Strachan <jstrachan@apache.org>.  For more information on the 
 43  
  * Jaxen Project, please see <http://www.jaxen.org/>.
 44  
  * 
 45  
  * $Id: NumberFunction.java,v 1.18 2006/02/05 21:47:41 elharo Exp $
 46  
  */
 47  
 
 48  
 package org.jaxen.function;
 49  
 
 50  
 import java.util.Iterator;
 51  
 import java.util.List;
 52  
 
 53  
 import org.jaxen.Context;
 54  
 import org.jaxen.Function;
 55  
 import org.jaxen.FunctionCallException;
 56  
 import org.jaxen.Navigator;
 57  
 
 58  
 /**
 59  
  * <p>
 60  
  * <b>4.4</b> <code><i>number</i> number(<i>object</i>)</code>
 61  
  * 
 62  
  * 
 63  
  * <blockquote src="http://www.w3.org/TR/xpath#function-number">
 64  
  * <p>
 65  
  * The <b>number</b> function converts
 66  
  * its argument to a number as follows:
 67  
  * </p>
 68  
  * 
 69  
  * <ul>
 70  
  * 
 71  
  * <li>
 72  
  * <p>
 73  
  * a string that consists of optional whitespace followed by an optional
 74  
  * minus sign followed by a <a href="#NT-Number">Number</a> followed by
 75  
  * whitespace is converted to the IEEE 754 number that is nearest
 76  
  * (according to the IEEE 754 round-to-nearest rule) to the mathematical
 77  
  * value represented by the string; any other string is converted to NaN
 78  
  * </p>
 79  
  * </li>
 80  
  * 
 81  
  * <li>
 82  
  * <p>
 83  
  * boolean true is converted to 1; boolean false is converted to 0
 84  
  * </p>
 85  
  * </li>
 86  
  * 
 87  
  * <li>
 88  
  * 
 89  
  * <p>
 90  
  * a node-set is first converted to a string as if by a call to the <b><a
 91  
  * href="http://www.w3.org/TR/xpath#function-string" target="_top">string</a></b> function and then converted
 92  
  * in the same way as a string argument
 93  
  * </p>
 94  
  * 
 95  
  * </li>
 96  
  * 
 97  
  * <li>
 98  
  * <p>
 99  
  * an object of a type other than the four basic types is converted to a
 100  
  * number in a way that is dependent on that type
 101  
  * </p>
 102  
  * </li>
 103  
  * 
 104  
  * </ul>
 105  
  * 
 106  
  * <p>
 107  
  * If the argument is omitted, it defaults to a node-set with the
 108  
  * context node as its only member.
 109  
  * </p>
 110  
  * 
 111  
  * <blockquote> <b>NOTE: </b>The <b>number</b>
 112  
  * function should not be used for conversion of numeric data occurring
 113  
  * in an element in an XML document unless the element is of a type that
 114  
  * represents numeric data in a language-neutral format (which would
 115  
  * typically be transformed into a language-specific format for
 116  
  * presentation to a user). In addition, the <b>number</b> function cannot be used
 117  
  * unless the language-neutral format used by the element is consistent
 118  
  * with the XPath syntax for a <a href="http://www.w3.org/TR/xpath#NT-Number">Number</a>.</blockquote>
 119  
  * 
 120  
  * </blockquote>
 121  
  * 
 122  
  * @author bob mcwhirter (bob @ werken.com)
 123  
  * 
 124  
  * @see <a href="http://www.w3.org/TR/xpath#function-number"
 125  
  *      target="_top">Section 4.4 of the XPath Specification</a>
 126  
  */
 127  
 public class NumberFunction implements Function
 128  
 {
 129  
 
 130  104
     private final static Double NaN = new Double( Double.NaN );
 131  
     
 132  
     
 133  
     /**
 134  
      * Create a new <code>NumberFunction</code> object.
 135  
      */
 136  106
     public NumberFunction() {}
 137  
 
 138  
     /** 
 139  
      * Returns the number value of <code>args.get(0)</code>,
 140  
      * or the number value of the context node if <code>args</code>
 141  
      * is empty.
 142  
      *
 143  
      * @param context the context at the point in the
 144  
      *         expression when the function is called
 145  
      * @param args a list containing the single item to be converted to a 
 146  
      *     <code>Double</code>
 147  
      * 
 148  
      * @return a <code>Double</code>
 149  
      * 
 150  
      * @throws FunctionCallException if <code>args</code> has more than one item
 151  
      */
 152  
     public Object call(Context context, List args) throws FunctionCallException
 153  
     {
 154  8
         if (args.size() == 1)
 155  
         {
 156  4
             return evaluate( args.get(0), context.getNavigator() );
 157  
         }
 158  4
         else if (args.size() == 0)
 159  
         {
 160  2
             return evaluate( context.getNodeSet(), context.getNavigator() );
 161  
         }
 162  
     
 163  2
         throw new FunctionCallException( "number() takes at most one argument." );
 164  
     }
 165  
 
 166  
     /** 
 167  
      * Returns the number value of <code>obj</code>.
 168  
      *
 169  
      * @param obj the object to be converted to a number
 170  
      * @param nav the <code>Navigator</code> used to calculate the string-value
 171  
      *     of node-sets
 172  
      * 
 173  
      * @return a <code>Double</code>
 174  
      */
 175  
     public static Double evaluate(Object obj, Navigator nav)
 176  
     {
 177  4894
         if( obj instanceof Double )
 178  
         {
 179  3152
             return (Double) obj;
 180  
         }
 181  1742
         else if ( obj instanceof String )
 182  
         {
 183  816
             String str = (String) obj;
 184  
             try
 185  
             {
 186  816
                 Double doubleValue = new Double( str );        
 187  814
                 return doubleValue;
 188  
             }
 189  2
             catch (NumberFormatException e)
 190  
             {
 191  2
                 return NaN;
 192  
             }
 193  
         }
 194  926
         else if ( obj instanceof List || obj instanceof Iterator )
 195  
         {
 196  6
           return evaluate( StringFunction.evaluate( obj, nav ), nav );
 197  
         }
 198  920
         else if ( nav.isElement( obj ) || nav.isAttribute( obj ) )
 199  
         {
 200  808
             return evaluate( StringFunction.evaluate( obj, nav ), nav );
 201  
         }
 202  112
         else if ( obj instanceof Boolean )
 203  
           {
 204  110
           if ( obj == Boolean.TRUE )
 205  
           {
 206  94
               return new Double( 1 );
 207  
           }
 208  
           else
 209  
           {
 210  16
               return new Double( 0 );
 211  
           }
 212  
         }    
 213  2
         return NaN;
 214  
     }
 215  
   
 216  
   /**
 217  
    * Determines whether the argument is not a number (NaN) as defined
 218  
    * by IEEE 754.
 219  
    * 
 220  
    * @param val the double to test
 221  
    * @return true if the value is NaN, false otherwise
 222  
    */
 223  
     public static boolean isNaN( double val )
 224  
     {
 225  2
         return Double.isNaN(val);
 226  
     }
 227  
   
 228  
   /**
 229  
    * Determines whether the argument is not a number (NaN) as defined
 230  
    * by IEEE 754.
 231  
    * 
 232  
    * @param val the <code>Double</code> to test
 233  
    * @return true if the value is NaN, false otherwise
 234  
    */
 235  
     public static boolean isNaN( Double val )
 236  
     {
 237  1860
         return val.equals( NaN );
 238  
     }  
 239  
   
 240  
 }