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 | } |