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1 /* |
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2 * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved. |
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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4 * |
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5 * This code is free software; you can redistribute it and/or modify it |
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6 * under the terms of the GNU General Public License version 2 only, as |
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7 * published by the Free Software Foundation. Oracle designates this |
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8 * particular file as subject to the "Classpath" exception as provided |
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9 * by Oracle in the LICENSE file that accompanied this code. |
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10 * |
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11 * This code is distributed in the hope that it will be useful, but WITHOUT |
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12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
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14 * version 2 for more details (a copy is included in the LICENSE file that |
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15 * accompanied this code). |
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16 * |
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17 * You should have received a copy of the GNU General Public License version |
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18 * 2 along with this work; if not, write to the Free Software Foundation, |
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19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
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20 * |
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21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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22 * or visit www.oracle.com if you need additional information or have any |
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23 * questions. |
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24 */ |
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25 |
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26 package com.sun.xml.internal.bind; |
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27 |
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28 import java.util.concurrent.Callable; |
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29 |
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30 import javax.xml.bind.Unmarshaller; |
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31 import javax.xml.bind.ValidationEventHandler; |
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32 import javax.xml.bind.annotation.XmlIDREF; |
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33 |
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34 import org.xml.sax.SAXException; |
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35 |
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36 /** |
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37 * Pluggable ID/IDREF handling layer. |
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38 * |
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39 * <p> |
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40 * <b>THIS INTERFACE IS SUBJECT TO CHANGE WITHOUT NOTICE.</b> |
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41 * |
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42 * <p> |
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43 * This 'interface' can be implemented by applications and specified to |
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44 * {@link Unmarshaller#setProperty(String, Object)} to ovierride the ID/IDREF |
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45 * processing of the JAXB RI like this: |
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46 * |
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47 * <pre> |
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48 * unmarshaller.setProperty(IDResolver.class.getName(),new MyIDResolverImpl()); |
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49 * </pre> |
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50 * |
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51 * <h2>Error Handling</h2> |
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52 * <p> |
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53 * This component runs inside the JAXB RI unmarshaller. Therefore, it needs |
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54 * to coordinate with the JAXB RI unmarshaller when it comes to reporting |
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55 * errors. This makes sure that applications see consistent error handling behaviors. |
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56 * |
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57 * <p> |
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58 * When the {@link #startDocument(ValidationEventHandler)} method is invoked, |
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59 * the unmarshaller passes in a {@link ValidationEventHandler} that can be used |
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60 * by this component to report any errors encountered during the ID/IDREF processing. |
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61 * |
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62 * <p> |
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63 * When an error is detected, the error should be first reported to this |
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64 * {@link ValidationEventHandler}. If the error is fatal or the event handler |
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65 * decided to abort, the implementation should throw a {@link SAXException}. |
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66 * This signals the unmarshaller to abort the processing. |
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67 * |
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68 * @author Kohsuke Kawaguchi |
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69 * @since JAXB 2.0 beta |
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70 */ |
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71 public abstract class IDResolver { |
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72 |
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73 /** |
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74 * Called when the unmarshalling starts. |
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75 * |
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76 * <p> |
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77 * Since one {@link Unmarshaller} may be used multiple times |
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78 * to unmarshal documents, one {@link IDResolver} may be used multiple times, too. |
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79 * |
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80 * @param eventHandler |
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81 * Any errors found during the unmarshalling should be reported to this object. |
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82 */ |
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83 public void startDocument(ValidationEventHandler eventHandler) throws SAXException { |
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84 |
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85 } |
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86 |
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87 /** |
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88 * Called after the unmarshalling completes. |
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89 * |
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90 * <p> |
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91 * This is a good opporunity to reset any internal state of this object, |
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92 * so that it doesn't keep references to other objects unnecessarily. |
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93 */ |
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94 public void endDocument() throws SAXException { |
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95 |
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96 } |
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97 |
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98 /** |
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99 * Binds the given object to the specified ID. |
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100 * |
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101 * <p> |
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102 * While a document is being unmarshalled, every time |
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103 * an ID value is found, this method is invoked to |
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104 * remember the association between ID and objects. |
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105 * This association is supposed to be used later to resolve |
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106 * IDREFs. |
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107 * |
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108 * <p> |
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109 * This method is invoked right away as soon as a new ID value is found. |
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110 * |
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111 * @param id |
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112 * The ID value found in the document being unmarshalled. |
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113 * Always non-null. |
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114 * @param obj |
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115 * The object being unmarshalled which is going to own the ID. |
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116 * Always non-null. |
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117 */ |
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118 public abstract void bind( String id, Object obj ) throws SAXException; |
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119 |
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120 /** |
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121 * Obtains the object to be pointed by the IDREF value. |
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122 * |
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123 * <p> |
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124 * While a document is being unmarshalled, every time |
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125 * an IDREF value is found, this method is invoked immediately to |
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126 * obtain the object that the IDREF is pointing to. |
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127 * |
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128 * <p> |
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129 * This method returns a {@link Callable} to support forward-references. |
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130 * When this method returns with a non-null return value, |
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131 * the JAXB RI unmarshaller invokes the {@link Callable#call()} method immediately. |
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132 * If the implementation can find the target object (in which case |
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133 * it was a backward reference), then a non-null object shall be returned, |
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134 * and it is used as the target object. |
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135 * |
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136 * <p> |
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137 * When a forward-reference happens, the <tt>call</tt> method |
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138 * should return null. In this case the JAXB RI unmarshaller invokes |
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139 * the <tt>call</tt> method again after all the documents are fully unmarshalled. |
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140 * If the <tt>call</tt> method still returns null, then the JAXB RI unmarshaller |
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141 * treats it as an error. |
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142 * |
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143 * <p> |
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144 * A {@link Callable} object returned from this method may not throw |
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145 * any exception other than a {@link SAXException} (which means a fatal error.) |
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146 * |
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147 * @param id |
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148 * The IDREF value found in the document being unmarshalled. |
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149 * Always non-null. |
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150 * @param targetType |
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151 * The expected type to which ID resolves to. JAXB infers this |
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152 * information from the signature of the fields that has {@link XmlIDREF}. |
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153 * When a property is a collection, this parameter will be the type |
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154 * of the individual item in the collection. |
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155 * @return |
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156 * null if the implementation is sure that the parameter combination |
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157 * will never yield a valid object. Otherwise non-null. |
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158 */ |
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159 public abstract Callable<?> resolve( String id, Class targetType ) throws SAXException; |
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160 } |