| Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||||||
| BooleanFunction |
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| 5.666666666666667;5.667 |
| 1 | /* |
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| 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 $ |
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| 3 | * $Revision: 1.16 $ |
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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: BooleanFunction.java,v 1.16 2005/06/28 13:44:45 elharo Exp $ |
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| 60 | */ |
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| 61 | ||
| 62 | ||
| 63 | package org.jaxen.function; |
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| 64 | ||
| 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>4.3</b> <code><i>boolean</i> boolean(<i>object</i>)</code> |
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| 75 | * </p> |
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| 76 | * |
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| 77 | * <blockquote |
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| 78 | * src="http://www.w3.org/TR/xpath#section-Boolean-Functions"> |
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| 79 | * <p> |
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| 80 | * The <b><a href="http://www.w3.org/TR/xpath#function-boolean" target="_top">boolean</a></b> |
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| 81 | * function converts its argument to a boolean as follows: |
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| 82 | * </p> |
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| 83 | * |
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| 84 | * <ul> |
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| 85 | * |
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| 86 | * <li> |
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| 87 | * <p> |
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| 88 | * a number is true if and only if it is neither positive or negative |
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| 89 | * zero nor NaN |
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| 90 | * </p> |
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| 91 | * </li> |
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| 92 | * |
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| 93 | * <li> |
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| 94 | * <p> |
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| 95 | * a node-set is true if and only if it is non-empty |
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| 96 | * </p> |
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| 97 | * </li> |
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| 98 | * |
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| 99 | * <li> |
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| 100 | * <p> |
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| 101 | * a string is true if and only if its length is non-zero |
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| 102 | * </p> |
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| 103 | * </li> |
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| 104 | * |
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| 105 | * <li> |
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| 106 | * |
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| 107 | * <p> |
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| 108 | * an object of a type other than the four basic types is converted to a |
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| 109 | * boolean in a way that is dependent on that type |
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| 110 | * </p></li></ul> |
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| 111 | * </blockquote> |
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| 112 | * |
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| 113 | * @author bob mcwhirter (bob @ werken.com) |
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| 114 | * @see <a href="http://www.w3.org/TR/xpath#function-boolean">Section 4.3 of the XPath Specification</a> |
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| 115 | */ |
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| 116 | public class BooleanFunction implements Function |
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| 117 | { |
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| 118 | ||
| 119 | ||
| 120 | /** |
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| 121 | * Create a new <code>BooleanFunction</code> object. |
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| 122 | */ |
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| 123 | 294 | public BooleanFunction() {} |
| 124 | ||
| 125 | /** Convert the argument to a <code>Boolean</code> |
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| 126 | * |
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| 127 | * @param context the context at the point in the |
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| 128 | * expression when the function is called |
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| 129 | * @param args a list with exactly one item which will be converted to a |
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| 130 | * <code>Boolean</code> |
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| 131 | * |
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| 132 | * @return the result of evaluating the function; |
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| 133 | * <code>Boolean.TRUE</code> or <code>Boolean.FALSE</code> |
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| 134 | * |
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| 135 | * @throws FunctionCallException if <code>args</code> has more or less than one item |
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| 136 | */ |
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| 137 | public Object call(Context context, |
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| 138 | List args) throws FunctionCallException |
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| 139 | { |
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| 140 | 48 | if ( args.size() == 1 ) |
| 141 | { |
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| 142 | 36 | return evaluate( args.get(0), context.getNavigator() ); |
| 143 | } |
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| 144 | ||
| 145 | 12 | throw new FunctionCallException("boolean() requires one argument"); |
| 146 | } |
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| 147 | ||
| 148 | /** |
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| 149 | * <p>Convert the argument <code>obj</code> to a <code>Boolean</code> |
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| 150 | * according to the following rules:</p> |
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| 151 | * |
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| 152 | * <ul> |
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| 153 | * <li>Lists are false if they're empty; true if they're not.</li> |
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| 154 | * <li>Booleans are false if they're false; true if they're true.</li> |
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| 155 | * <li>Strings are false if they're empty; true if they're not.</li> |
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| 156 | * <li>Numbers are false if they're 0 or NaN; true if they're not.</li> |
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| 157 | * <li>All other objects are true.</li> |
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| 158 | * </ul> |
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| 159 | * |
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| 160 | * @param obj the object to convert to a boolean |
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| 161 | * @param nav ignored |
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| 162 | * |
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| 163 | * @return <code>Boolean.TRUE</code> or <code>Boolean.FALSE</code> |
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| 164 | */ |
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| 165 | public static Boolean evaluate(Object obj, Navigator nav) |
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| 166 | { |
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| 167 | 21486 | if ( obj instanceof List ) |
| 168 | { |
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| 169 | 1302 | List list = (List) obj; |
| 170 | ||
| 171 | // if it's an empty list, then we have a null node-set -> false |
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| 172 | 1302 | if (list.size() == 0) |
| 173 | { |
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| 174 | 18 | return Boolean.FALSE; |
| 175 | } |
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| 176 | ||
| 177 | // otherwise, unwrap the list and check the primitive |
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| 178 | 1284 | obj = list.get(0); |
| 179 | } |
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| 180 | ||
| 181 | // now check for primitive types |
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| 182 | // otherwise a non-empty node-set is true |
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| 183 | ||
| 184 | // if it's a Boolean, let it decide |
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| 185 | 21468 | if ( obj instanceof Boolean ) |
| 186 | { |
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| 187 | 19956 | return (Boolean) obj; |
| 188 | } |
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| 189 | // if it's a Number, != 0 -> true |
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| 190 | 1512 | else if ( obj instanceof Number ) |
| 191 | { |
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| 192 | 222 | double d = ((Number) obj).doubleValue(); |
| 193 | 222 | if ( d == 0 || Double.isNaN(d) ) |
| 194 | { |
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| 195 | 48 | return Boolean.FALSE; |
| 196 | } |
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| 197 | 174 | return Boolean.TRUE; |
| 198 | } |
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| 199 | // if it's a String, "" -> false |
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| 200 | 1290 | else if ( obj instanceof String ) |
| 201 | { |
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| 202 | 24 | return ( ((String)obj).length() > 0 |
| 203 | ? Boolean.TRUE |
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| 204 | : Boolean.FALSE ); |
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| 205 | } |
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| 206 | else |
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| 207 | { |
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| 208 | // assume it's a node so that this node-set is non-empty |
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| 209 | // and so it's true |
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| 210 | 1266 | return ( obj != null ) ? Boolean.TRUE : Boolean.FALSE; |
| 211 | } |
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| 212 | ||
| 213 | } |
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| 214 | } |