Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||||||
XPathReaderFactory |
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| 5.0;5 |
1 | /* |
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2 | * $Header: /home/projects/jaxen/scm/jaxen/src/java/main/org/jaxen/saxpath/helpers/XPathReaderFactory.java,v 1.7 2005/06/28 13:44:46 elharo Exp $ |
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3 | * $Revision: 1.7 $ |
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4 | * $Date: 2005/06/28 13:44:46 $ |
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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: XPathReaderFactory.java,v 1.7 2005/06/28 13:44:46 elharo Exp $ |
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60 | */ |
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61 | ||
62 | ||
63 | ||
64 | ||
65 | package org.jaxen.saxpath.helpers; |
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66 | ||
67 | import org.jaxen.saxpath.SAXPathException; |
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68 | import org.jaxen.saxpath.XPathReader; |
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69 | ||
70 | /** Create an {@link org.jaxen.saxpath.XPathReader} from |
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71 | * either a system property, or a named class. |
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72 | * |
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73 | * <p> |
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74 | * Similar to the SAX API, the <code>XPathReaderFactory</code> |
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75 | * can create an <code>XPathReader</code> from a name of a |
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76 | * class passed in directly, or by inspecting the system |
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77 | * property <code>org.saxpath.driver</code>. |
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78 | * |
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79 | * @author bob mcwhirter (bob@werken.com) |
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80 | */ |
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81 | public class XPathReaderFactory |
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82 | { |
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83 | /** The <code>org.saxpath.driver</code> property name. */ |
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84 | public static final String DRIVER_PROPERTY = "org.saxpath.driver"; |
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85 | ||
86 | /** The default driver to use if none is configured. */ |
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87 | protected static final String DEFAULT_DRIVER = "org.jaxen.saxpath.base.XPathReader"; |
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88 | ||
89 | 0 | private XPathReaderFactory() {} |
90 | ||
91 | ||
92 | /** Create an <code>XPathReader</code> using the value of |
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93 | * the <code>org.saxpath.driver</code> system property. |
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94 | * |
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95 | * @return an instance of the <code>XPathReader</code> specified |
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96 | * by the <code>org.saxpath.driver</code> property |
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97 | * |
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98 | * @throws SAXPathException if the property is not set, or if |
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99 | * the class can not be instantiated for some reason, |
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100 | * or if the class doesn't implement the <code>XPathReader</code> |
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101 | * interface |
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102 | */ |
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103 | public static XPathReader createReader() throws SAXPathException |
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104 | { |
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105 | 10752 | String className = null; |
106 | ||
107 | try |
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108 | { |
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109 | 10752 | className = System.getProperty( DRIVER_PROPERTY ); |
110 | } |
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111 | 0 | catch (SecurityException e) |
112 | { |
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113 | // we'll use the default |
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114 | 10752 | } |
115 | ||
116 | 10752 | if ( className == null |
117 | || |
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118 | className.length() == 0 ) |
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119 | { |
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120 | 10728 | className = DEFAULT_DRIVER; |
121 | } |
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122 | ||
123 | 10752 | return createReader( className ); |
124 | } |
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125 | ||
126 | /** Create an <code>XPathReader</code> using the passed |
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127 | * in class name. |
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128 | * |
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129 | * @param className the name of the class that implements |
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130 | * the <code>XPathReader</code> interface. |
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131 | * |
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132 | * @return an XPathReader |
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133 | * |
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134 | * @throws SAXPathException if the class cannot be |
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135 | * instantiated for some reason, or if the |
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136 | * class doesn't implement the <code>XPathReader</code> |
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137 | * interface |
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138 | */ |
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139 | public static XPathReader createReader(String className) throws SAXPathException |
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140 | { |
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141 | 10770 | Class readerClass = null; |
142 | 10770 | XPathReader reader = null; |
143 | ||
144 | try |
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145 | { |
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146 | // Use the full version of Class.forName(), so as to |
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147 | // work better in sandboxed environments, such as |
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148 | // servlet containers and applets. |
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149 | ||
150 | 10770 | readerClass = Class.forName( className, |
151 | true, |
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152 | 636 | XPathReaderFactory.class.getClassLoader() ); |
153 | ||
154 | // Double-check that it's actually the right kind of class |
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155 | // before attempting instantiation. |
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156 | ||
157 | 10758 | if ( ! XPathReader.class.isAssignableFrom( readerClass ) ) |
158 | { |
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159 | 18 | throw new SAXPathException( "Class [" + className |
160 | + "] does not implement the org.jaxen.saxpath.XPathReader interface." ); |
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161 | } |
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162 | } |
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163 | 12 | catch (ClassNotFoundException e) |
164 | { |
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165 | 12 | throw new SAXPathException( e ); |
166 | 10740 | } |
167 | ||
168 | try |
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169 | { |
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170 | 10740 | reader = (XPathReader) readerClass.newInstance(); |
171 | } |
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172 | 0 | catch (IllegalAccessException e) |
173 | { |
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174 | 0 | throw new SAXPathException( e ); |
175 | } |
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176 | 0 | catch (InstantiationException e) |
177 | { |
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178 | 0 | throw new SAXPathException( e ); |
179 | 10740 | } |
180 | ||
181 | 10740 | if ( reader == null ) |
182 | { |
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183 | 0 | throw new SAXPathException( "Unable to create XPathReader" ); |
184 | } |
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185 | ||
186 | 10740 | return reader; |
187 | } |
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188 | } |