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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
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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
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19   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20   *
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24   */
25  
26  package javax.xml.bind;
27  
28  /**
29   * A basic event handler interface for validation errors.
30   *
31   * <p>
32   * If an application needs to implement customized event handling, it must
33   * implement this interface and then register it with either the
34   * {@link Unmarshaller#setEventHandler(ValidationEventHandler) Unmarshaller},
35   * the {@link Validator#setEventHandler(ValidationEventHandler) Validator}, or
36   * the {@link Marshaller#setEventHandler(ValidationEventHandler) Marshaller}.
37   * The JAXB Provider will then report validation errors and warnings encountered
38   * during the unmarshal, marshal, and validate operations to these event
39   * handlers.
40   *
41   * <p>
42   * If the <tt>handleEvent</tt> method throws an unchecked runtime exception,
43   * the JAXB Provider must treat that as if the method returned false, effectively
44   * terminating whatever operation was in progress at the time (unmarshal,
45   * validate, or marshal).
46   *
47   * <p>
48   * Modifying the Java content tree within your event handler is undefined
49   * by the specification and may result in unexpected behaviour.
50   *
51   * <p>
52   * Failing to return false from the <tt>handleEvent</tt> method after
53   * encountering a fatal error is undefined by the specification and may result
54   * in unexpected behavior.
55   *
56   * <p>
57   * <b>Default Event Handler</b>
58   * <blockquote>
59   *    See: <a href="Validator.html#defaulthandler">Validator javadocs</a>
60   * </blockquote>
61   *
62   * @author <ul><li>Ryan Shoemaker, Sun Microsystems, Inc.</li><li>Kohsuke Kawaguchi, Sun Microsystems, Inc.</li><li>Joe Fialli, Sun Microsystems, Inc.</li></ul>
63   * @see Unmarshaller
64   * @see Validator
65   * @see Marshaller
66   * @see ValidationEvent
67   * @see javax.xml.bind.util.ValidationEventCollector
68   * @since JAXB1.0
69   */
70  public interface ValidationEventHandler {
71      /**
72       * Receive notification of a validation warning or error.
73       *
74       * The ValidationEvent will have a
75       * {@link ValidationEventLocator ValidationEventLocator} embedded in it that
76       * indicates where the error or warning occurred.
77       *
78       * <p>
79       * If an unchecked runtime exception is thrown from this method, the JAXB
80       * provider will treat it as if the method returned false and interrupt
81       * the current unmarshal, validate, or marshal operation.
82       *
83       * @param event the encapsulated validation event information.  It is a
84       * provider error if this parameter is null.
85       * @return true if the JAXB Provider should attempt to continue the current
86       *         unmarshal, validate, or marshal operation after handling this
87       *         warning/error, false if the provider should terminate the current
88       *         operation with the appropriate <tt>UnmarshalException</tt>,
89       *         <tt>ValidationException</tt>, or <tt>MarshalException</tt>.
90       * @throws IllegalArgumentException if the event object is null.
91       */
92      public boolean handleEvent( ValidationEvent event );
93  
94  }