Coverage Report - org.jaxen.function.BooleanFunction

Classes in this File Line Coverage Branch Coverage Complexity
BooleanFunction
100% 
100% 
5.667

 1  
 /*
 2  
  * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/BooleanFunction.java,v 1.16 2005/06/28 13:44:45 elharo Exp $
 3  
  * $Revision: 1.16 $
 4  
  * $Date: 2005/06/28 13:44:45 $
 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: BooleanFunction.java,v 1.16 2005/06/28 13:44:45 elharo Exp $
 60  
  */
 61  
 
 62  
 
 63  
 package org.jaxen.function;
 64  
 
 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>
 74  
  * <b>4.3</b> <code><i>boolean</i> boolean(<i>object</i>)</code>
 75  
  * </p>
 76  
  * 
 77  
  * <blockquote
 78  
  * src="http://www.w3.org/TR/xpath#section-Boolean-Functions">
 79  
  * <p>
 80  
  * The <b><a href="http://www.w3.org/TR/xpath#function-boolean" target="_top">boolean</a></b>
 81  
  * function converts its argument to a boolean as follows:
 82  
  * </p>
 83  
  * 
 84  
  * <ul>
 85  
  * 
 86  
  * <li>
 87  
  * <p>
 88  
  * a number is true if and only if it is neither positive or negative
 89  
  * zero nor NaN
 90  
  * </p>
 91  
  * </li>
 92  
  * 
 93  
  * <li>
 94  
  * <p>
 95  
  * a node-set is true if and only if it is non-empty
 96  
  * </p>
 97  
  * </li>
 98  
  * 
 99  
  * <li>
 100  
  * <p>
 101  
  * a string is true if and only if its length is non-zero
 102  
  * </p>
 103  
  * </li>
 104  
  * 
 105  
  * <li>
 106  
  * 
 107  
  * <p>
 108  
  * an object of a type other than the four basic types is converted to a
 109  
  * boolean in a way that is dependent on that type
 110  
  * </p></li></ul>
 111  
  * </blockquote>
 112  
  * 
 113  
  * @author bob mcwhirter (bob @ werken.com)
 114  
  * @see <a href="http://www.w3.org/TR/xpath#function-boolean">Section 4.3 of the XPath Specification</a>
 115  
  */
 116  
 public class BooleanFunction implements Function
 117  
 {
 118  
 
 119  
 
 120  
     /**
 121  
      * Create a new <code>BooleanFunction</code> object.
 122  
      */
 123  294
     public BooleanFunction() {}
 124  
     
 125  
     /** Convert the argument to a <code>Boolean</code>
 126  
      *
 127  
      * @param context the context at the point in the
 128  
      *         expression when the function is called
 129  
      * @param args a list with exactly one item which will be converted to a 
 130  
      *     <code>Boolean</code>
 131  
      * 
 132  
      * @return the result of evaluating the function; 
 133  
      *     <code>Boolean.TRUE</code> or <code>Boolean.FALSE</code>
 134  
      * 
 135  
      * @throws FunctionCallException if <code>args</code> has more or less than one item
 136  
      */
 137  
     public Object call(Context context,
 138  
                        List args) throws FunctionCallException
 139  
     {
 140  48
         if ( args.size() == 1 )
 141  
         {
 142  36
             return evaluate( args.get(0), context.getNavigator() );
 143  
         }
 144  
 
 145  12
         throw new FunctionCallException("boolean() requires one argument");
 146  
     }
 147  
 
 148  
     /** 
 149  
      * <p>Convert the argument <code>obj</code> to a <code>Boolean</code> 
 150  
      * according to the following rules:</p>
 151  
      *
 152  
      * <ul>
 153  
      * <li>Lists are false if they're empty; true if they're not.</li>
 154  
      * <li>Booleans are false if they're false; true if they're true.</li>
 155  
      * <li>Strings are false if they're empty; true if they're not.</li>
 156  
      * <li>Numbers are false if they're 0 or NaN; true if they're not.</li>
 157  
      * <li>All other objects are true.</li>
 158  
      * </ul>
 159  
      * 
 160  
      * @param obj the object to convert to a boolean
 161  
      * @param nav ignored
 162  
      * 
 163  
      * @return <code>Boolean.TRUE</code> or <code>Boolean.FALSE</code>
 164  
      */
 165  
     public static Boolean evaluate(Object obj, Navigator nav)
 166  
     {
 167  21486
         if ( obj instanceof List )
 168  
         {
 169  1302
             List list = (List) obj;
 170  
             
 171  
             // if it's an empty list, then we have a null node-set -> false            
 172  1302
             if (list.size() == 0)
 173  
             {
 174  18
                 return Boolean.FALSE;
 175  
             }
 176  
      
 177  
             // otherwise, unwrap the list and check the primitive
 178  1284
             obj = list.get(0);
 179  
         }
 180  
         
 181  
         // now check for primitive types
 182  
         // otherwise a non-empty node-set is true
 183  
 
 184  
         // if it's a Boolean, let it decide
 185  21468
         if ( obj instanceof Boolean )
 186  
         {
 187  19956
             return (Boolean) obj;
 188  
         }
 189  
         // if it's a Number, != 0 -> true
 190  1512
         else if ( obj instanceof Number )
 191  
         {
 192  222
             double d = ((Number) obj).doubleValue();
 193  222
             if ( d == 0 || Double.isNaN(d) )
 194  
             {
 195  48
                 return Boolean.FALSE;
 196  
             }
 197  174
             return Boolean.TRUE;
 198  
         }
 199  
         // if it's a String, "" -> false
 200  1290
         else if ( obj instanceof String )
 201  
         {
 202  24
             return ( ((String)obj).length() > 0
 203  
                      ? Boolean.TRUE
 204  
                      : Boolean.FALSE );
 205  
         }
 206  
         else 
 207  
         {
 208  
             // assume it's a node so that this node-set is non-empty 
 209  
             // and so it's true
 210  1266
             return ( obj != null ) ? Boolean.TRUE : Boolean.FALSE;
 211  
         }
 212  
 
 213  
     }
 214  
 }