| Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
| NumberFunction |
|
| 4.8;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 | } |