| Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||||||
| NumberFunction |
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| 4.8;4.8 |
| 1 | /* |
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| 2 | * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/function/NumberFunction.java,v 1.17 2005/06/28 13:44:45 elharo Exp $ |
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| 3 | * $Revision: 1.17 $ |
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| 4 | * $Date: 2005/06/28 13:44:45 $ |
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| 5 | * |
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| 6 | * ==================================================================== |
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| 7 | * |
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| 8 | * Copyright (C) 2000-2002 bob mcwhirter & James Strachan. |
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| 9 | * All rights reserved. |
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| 10 | * |
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| 11 | * Redistribution and use in source and binary forms, with or without |
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| 12 | * modification, are permitted provided that the following conditions |
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| 13 | * are met: |
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| 14 | * |
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| 15 | * 1. Redistributions of source code must retain the above copyright |
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| 16 | * notice, this list of conditions, and the following disclaimer. |
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| 17 | * |
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| 18 | * 2. Redistributions in binary form must reproduce the above copyright |
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| 19 | * notice, this list of conditions, and the disclaimer that follows |
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| 20 | * these conditions in the documentation and/or other materials |
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| 21 | * provided with the distribution. |
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| 22 | * |
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| 23 | * 3. The name "Jaxen" must not be used to endorse or promote products |
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| 24 | * derived from this software without prior written permission. For |
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| 25 | * written permission, please contact license@jaxen.org. |
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| 26 | * |
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| 27 | * 4. Products derived from this software may not be called "Jaxen", nor |
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| 28 | * may "Jaxen" appear in their name, without prior written permission |
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| 29 | * from the Jaxen Project Management (pm@jaxen.org). |
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| 30 | * |
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| 31 | * In addition, we request (but do not require) that you include in the |
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| 32 | * end-user documentation provided with the redistribution and/or in the |
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| 33 | * software itself an acknowledgement equivalent to the following: |
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| 34 | * "This product includes software developed by the |
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| 35 | * Jaxen Project <http://www.jaxen.org/>." |
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| 36 | * Alternatively, the acknowledgment may be graphical using the logos |
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| 37 | * available at http://www.jaxen.org/ |
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| 38 | * |
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| 39 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
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| 40 | * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 41 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
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| 42 | * DISCLAIMED. IN NO EVENT SHALL THE Jaxen AUTHORS OR THE PROJECT |
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| 43 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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| 44 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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| 45 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
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| 46 | * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
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| 47 | * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
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| 48 | * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
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| 49 | * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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| 50 | * SUCH DAMAGE. |
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| 51 | * |
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| 52 | * ==================================================================== |
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| 53 | * This software consists of voluntary contributions made by many |
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| 54 | * individuals on behalf of the Jaxen Project and was originally |
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| 55 | * created by bob mcwhirter <bob@werken.com> and |
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| 56 | * James Strachan <jstrachan@apache.org>. For more information on the |
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| 57 | * Jaxen Project, please see <http://www.jaxen.org/>. |
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| 58 | * |
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| 59 | * $Id: NumberFunction.java,v 1.17 2005/06/28 13:44:45 elharo Exp $ |
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| 60 | */ |
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| 61 | ||
| 62 | package org.jaxen.function; |
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| 63 | ||
| 64 | import java.util.Iterator; |
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| 65 | import java.util.List; |
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| 66 | ||
| 67 | import org.jaxen.Context; |
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| 68 | import org.jaxen.Function; |
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| 69 | import org.jaxen.FunctionCallException; |
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| 70 | import org.jaxen.Navigator; |
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| 71 | ||
| 72 | /** |
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| 73 | * <p> |
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| 74 | * <b>4.4</b> <code><i>number</i> number(<i>object</i>)</code> |
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| 75 | * |
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| 76 | * |
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| 77 | * <blockquote src="http://www.w3.org/TR/xpath#function-number"> |
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| 78 | * <p> |
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| 79 | * The <b>number</b> function converts |
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| 80 | * its argument to a number as follows: |
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| 81 | * </p> |
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| 82 | * |
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| 83 | * <ul> |
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| 84 | * |
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| 85 | * <li> |
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| 86 | * <p> |
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| 87 | * a string that consists of optional whitespace followed by an optional |
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| 88 | * minus sign followed by a <a href="#NT-Number">Number</a> followed by |
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| 89 | * whitespace is converted to the IEEE 754 number that is nearest |
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| 90 | * (according to the IEEE 754 round-to-nearest rule) to the mathematical |
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| 91 | * value represented by the string; any other string is converted to NaN |
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| 92 | * </p> |
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| 93 | * </li> |
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| 94 | * |
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| 95 | * <li> |
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| 96 | * <p> |
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| 97 | * boolean true is converted to 1; boolean false is converted to 0 |
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| 98 | * </p> |
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| 99 | * </li> |
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| 100 | * |
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| 101 | * <li> |
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| 102 | * |
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| 103 | * <p> |
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| 104 | * a node-set is first converted to a string as if by a call to the <b><a |
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| 105 | * href="http://www.w3.org/TR/xpath#function-string" target="_top">string</a></b> function and then converted |
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| 106 | * in the same way as a string argument |
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| 107 | * </p> |
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| 108 | * |
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| 109 | * </li> |
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| 110 | * |
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| 111 | * <li> |
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| 112 | * <p> |
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| 113 | * an object of a type other than the four basic types is converted to a |
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| 114 | * number in a way that is dependent on that type |
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| 115 | * </p> |
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| 116 | * </li> |
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| 117 | * |
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| 118 | * </ul> |
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| 119 | * |
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| 120 | * <p> |
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| 121 | * If the argument is omitted, it defaults to a node-set with the |
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| 122 | * context node as its only member. |
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| 123 | * </p> |
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| 124 | * |
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| 125 | * <blockquote> <b>NOTE: </b>The <b>number</b> |
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| 126 | * function should not be used for conversion of numeric data occurring |
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| 127 | * in an element in an XML document unless the element is of a type that |
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| 128 | * represents numeric data in a language-neutral format (which would |
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| 129 | * typically be transformed into a language-specific format for |
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| 130 | * presentation to a user). In addition, the <b>number</b> function cannot be used |
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| 131 | * unless the language-neutral format used by the element is consistent |
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| 132 | * with the XPath syntax for a <a href="http://www.w3.org/TR/xpath#NT-Number">Number</a>.</blockquote> |
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| 133 | * |
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| 134 | * </blockquote> |
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| 135 | * |
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| 136 | * @author bob mcwhirter (bob @ werken.com) |
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| 137 | * |
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| 138 | * @see <a href="http://www.w3.org/TR/xpath#function-number" |
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| 139 | * target="_top">Section 4.4 of the XPath Specification</a> |
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| 140 | */ |
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| 141 | public class NumberFunction implements Function |
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| 142 | { |
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| 143 | ||
| 144 | 288 | private final static Double NaN = new Double( Double.NaN ); |
| 145 | ||
| 146 | ||
| 147 | /** |
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| 148 | * Create a new <code>NumberFunction</code> object. |
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| 149 | */ |
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| 150 | 294 | public NumberFunction() {} |
| 151 | ||
| 152 | /** |
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| 153 | * Returns the number value of <code>args.get(0)</code>, |
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| 154 | * or the number value of the context node if <code>args</code> |
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| 155 | * is empty. |
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| 156 | * |
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| 157 | * @param context the context at the point in the |
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| 158 | * expression when the function is called |
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| 159 | * @param args a list containing the single item to be converted to a |
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| 160 | * <code>Double</code> |
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| 161 | * |
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| 162 | * @return a <code>Double</code> |
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| 163 | * |
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| 164 | * @throws FunctionCallException if <code>args</code> has more than one item |
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| 165 | */ |
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| 166 | public Object call(Context context, List args) throws FunctionCallException |
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| 167 | { |
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| 168 | 24 | if (args.size() == 1) |
| 169 | { |
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| 170 | 12 | return evaluate( args.get(0), context.getNavigator() ); |
| 171 | } |
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| 172 | 12 | else if (args.size() == 0) |
| 173 | { |
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| 174 | 6 | return evaluate( context.getNodeSet(), context.getNavigator() ); |
| 175 | } |
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| 176 | ||
| 177 | 6 | throw new FunctionCallException( "number() takes at most one argument." ); |
| 178 | } |
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| 179 | ||
| 180 | /** |
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| 181 | * Returns the number value of <code>obj</code>. |
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| 182 | * |
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| 183 | * @param obj the object to be converted to a number |
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| 184 | * @param nav the <code>Navigator</code> used to calculate the string-value |
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| 185 | * of node-sets |
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| 186 | * |
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| 187 | * @return a <code>Double</code> |
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| 188 | */ |
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| 189 | public static Double evaluate(Object obj, Navigator nav) |
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| 190 | { |
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| 191 | 13230 | if( obj instanceof Double ) |
| 192 | { |
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| 193 | 8112 | return (Double) obj; |
| 194 | } |
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| 195 | 5118 | else if ( obj instanceof String ) |
| 196 | { |
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| 197 | 2448 | String str = (String) obj; |
| 198 | try |
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| 199 | { |
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| 200 | 2448 | Double doubleValue = new Double( str ); |
| 201 | 2442 | return doubleValue; |
| 202 | } |
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| 203 | 6 | catch (NumberFormatException e) |
| 204 | { |
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| 205 | 6 | return NaN; |
| 206 | } |
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| 207 | } |
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| 208 | 2670 | else if ( obj instanceof List || obj instanceof Iterator ) |
| 209 | { |
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| 210 | 18 | return evaluate( StringFunction.evaluate( obj, nav ), nav ); |
| 211 | } |
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| 212 | 2652 | else if ( nav.isElement( obj ) || nav.isAttribute( obj ) ) |
| 213 | { |
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| 214 | 2424 | return evaluate( StringFunction.evaluate( obj, nav ), nav ); |
| 215 | } |
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| 216 | 228 | else if ( obj instanceof Boolean ) |
| 217 | { |
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| 218 | 222 | if ( obj == Boolean.TRUE ) |
| 219 | { |
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| 220 | 174 | return new Double( 1 ); |
| 221 | } |
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| 222 | else |
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| 223 | { |
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| 224 | 48 | return new Double( 0 ); |
| 225 | } |
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| 226 | } |
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| 227 | 6 | return NaN; |
| 228 | } |
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| 229 | ||
| 230 | /** |
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| 231 | * Determines whether the argument is not a number (NaN) as defined |
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| 232 | * by IEEE 754. |
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| 233 | * |
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| 234 | * @param val the double to test |
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| 235 | * @return true if the value is NaN, false otherwise |
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| 236 | */ |
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| 237 | public static boolean isNaN( double val ) |
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| 238 | { |
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| 239 | 6 | return Double.isNaN(val); |
| 240 | } |
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| 241 | ||
| 242 | /** |
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| 243 | * Determines whether the argument is not a number (NaN) as defined |
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| 244 | * by IEEE 754. |
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| 245 | * |
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| 246 | * @param val the <code>Double</code> to test |
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| 247 | * @return true if the value is NaN, false otherwise |
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| 248 | */ |
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| 249 | public static boolean isNaN( Double val ) |
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| 250 | { |
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| 251 | 4848 | return val.equals( NaN ); |
| 252 | } |
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| 253 | ||
| 254 | } |