1 /*
   2  * Copyright (c) 2003, 2005, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package javax.xml.validation;
  27 
  28 import org.w3c.dom.TypeInfo;
  29 
  30 /**
  31  * This class provides access to the type information determined
  32  * by {@link ValidatorHandler}.
  33  *
  34  * <p>
  35  * Some schema languages, such as W3C XML Schema, encourages a validator
  36  * to report the "type" it assigns to each attribute/element.
  37  * Those applications who wish to access this type information can invoke
  38  * methods defined on this "interface" to access such type information.
  39  *
  40  * <p>
  41  * Implementation of this "interface" can be obtained through the
  42  * {@link ValidatorHandler#getTypeInfoProvider()} method.
  43  *
  44  * @author  Kohsuke Kawaguchi
  45  * @see org.w3c.dom.TypeInfo
  46  * @since 1.5
  47  */
  48 public abstract class TypeInfoProvider {
  49 
  50     /**
  51      * Constructor for the derived class.
  52      *
  53      * <p>
  54      * The constructor does nothing.
  55      */
  56     protected TypeInfoProvider() {
  57     }
  58 
  59     /**
  60      * <p>Returns the immutable {@link TypeInfo} object for the current
  61      * element.</p>
  62      *
  63      * <p>The method may only be called by the startElement event
  64      * or the endElement event
  65      * of the {@link org.xml.sax.ContentHandler} that the application sets to
  66      * the {@link ValidatorHandler}.</p>
  67      *
  68      * <p>When W3C XML Schema validation is being performed, in the
  69      * case where an element has a union type, the {@link TypeInfo}
  70      * returned by a call to <code>getElementTypeInfo()</code> from the
  71      * startElement
  72      * event will be the union type. The <code>TypeInfo</code>
  73      * returned by a call
  74      * from the endElement event will be the actual member type used
  75      * to validate the element.</p>
  76      *
  77      * @throws IllegalStateException
  78      *      If this method is called from other {@link org.xml.sax.ContentHandler}
  79      *      methods.
  80      * @return
  81      *      An immutable {@link TypeInfo} object that represents the
  82      *      type of the current element.
  83      *      Note that the caller can keep references to the obtained
  84      *      {@link TypeInfo} longer than the callback scope.
  85      *
  86      *      Otherwise, this method returns
  87      *      null if the validator is unable to
  88      *      determine the type of the current element for some reason
  89      *      (for example, if the validator is recovering from
  90      *      an earlier error.)
  91      *
  92      */
  93     public abstract TypeInfo getElementTypeInfo();
  94 
  95     /**
  96      * Returns the immutable {@link TypeInfo} object for the specified
  97      * attribute of the current element.
  98      *
  99      * <p>
 100      * The method may only be called by the startElement event of
 101      * the {@link org.xml.sax.ContentHandler} that the application sets to the
 102      * {@link ValidatorHandler}.</p>
 103      *
 104      * @param index
 105      *      The index of the attribute. The same index for
 106      *      the {@link org.xml.sax.Attributes} object passed to the
 107      *      <code>startElement</code> callback.
 108      *
 109      * @throws IndexOutOfBoundsException
 110      *      If the index is invalid.
 111      * @throws IllegalStateException
 112      *      If this method is called from other {@link org.xml.sax.ContentHandler}
 113      *      methods.
 114      *
 115      * @return
 116      *      An immutable {@link TypeInfo} object that represents the
 117      *      type of the specified attribute.
 118      *      Note that the caller can keep references to the obtained
 119      *      {@link TypeInfo} longer than the callback scope.
 120      *
 121      *      Otherwise, this method returns
 122      *      null if the validator is unable to
 123      *      determine the type.
 124      */
 125     public abstract TypeInfo getAttributeTypeInfo(int index);
 126 
 127     /**
 128      * Returns <code>true</code> if the specified attribute is determined
 129      * to be ID.
 130      *
 131      * <p>
 132      * Exacly how an attribute is "determined to be ID" is up to the
 133      * schema language. In case of W3C XML Schema, this means
 134      * that the actual type of the attribute is the built-in ID type
 135      * or its derived type.
 136      *
 137      * <p>
 138      * A {@link javax.xml.parsers.DocumentBuilder} uses this information
 139      * to properly implement {@link org.w3c.dom.Attr#isId()}.
 140      *
 141      * <p>
 142      * The method may only be called by the startElement event of
 143      * the {@link org.xml.sax.ContentHandler} that the application sets to the
 144      * {@link ValidatorHandler}.
 145      *
 146      * @param index
 147      *      The index of the attribute. The same index for
 148      *      the {@link org.xml.sax.Attributes} object passed to the
 149      *      <code>startElement</code> callback.
 150      *
 151      * @throws IndexOutOfBoundsException
 152      *      If the index is invalid.
 153      * @throws IllegalStateException
 154      *      If this method is called from other {@link org.xml.sax.ContentHandler}
 155      *      methods.
 156      *
 157      * @return true
 158      *      if the type of the specified attribute is ID.
 159      */
 160     public abstract boolean isIdAttribute(int index);
 161 
 162     /**
 163      * Returns <code>false</code> if the attribute was added by the validator.
 164      *
 165      * <p>
 166      * This method provides information necessary for
 167      * a {@link javax.xml.parsers.DocumentBuilder} to determine what
 168      * the DOM tree should return from the {@link org.w3c.dom.Attr#getSpecified()} method.
 169      *
 170      * <p>
 171      * The method may only be called by the startElement event of
 172      * the {@link org.xml.sax.ContentHandler} that the application sets to the
 173      * {@link ValidatorHandler}.
 174      *
 175      * <p>
 176      * A general guideline for validators is to return true if
 177      * the attribute was originally present in the pipeline, and
 178      * false if it was added by the validator.
 179      *
 180      * @param index
 181      *      The index of the attribute. The same index for
 182      *      the {@link org.xml.sax.Attributes} object passed to the
 183      *      <code>startElement</code> callback.
 184      *
 185      * @throws IndexOutOfBoundsException
 186      *      If the index is invalid.
 187      * @throws IllegalStateException
 188      *      If this method is called from other {@link org.xml.sax.ContentHandler}
 189      *      methods.
 190      *
 191      * @return
 192      *      <code>true</code> if the attribute was present before the validator
 193      *      processes input. <code>false</code> if the attribute was added
 194      *      by the validator.
 195      */
 196     public abstract boolean isSpecified(int index);
 197 }
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