/*
 * Copyright (c) 2003, 2018 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0, which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package javax.xml.bind;

A basic event handler interface for validation errors.
 If an application needs to implement customized event handling, it must implement this interface and then register it with either the Unmarshaller, the Validator, or the Marshaller. The JAXB Provider will then report validation errors and warnings encountered during the unmarshal, marshal, and validate operations to these event handlers. 
 If the handleEvent method throws an unchecked runtime exception, the JAXB Provider must treat that as if the method returned false, effectively terminating whatever operation was in progress at the time (unmarshal, validate, or marshal). 

Modifying the Java content tree within your event handler is undefined
by the specification and may result in unexpected behaviour.
 Failing to return false from the handleEvent method after encountering a fatal error is undefined by the specification and may result in unexpected behavior. 

Default Event Handler

   See: Validator javadocs

Author:
Ryan Shoemaker, Sun Microsystems, Inc.
            
Kohsuke Kawaguchi, Sun Microsystems, Inc.
            
Joe Fialli, Sun Microsystems, Inc.
See Also:
Unmarshaller
Validator
Marshaller
ValidationEvent
ValidationEventCollector
Since:
1.6, JAXB 1.0/**
 * A basic event handler interface for validation errors.
 *
 * <p>
 * If an application needs to implement customized event handling, it must
 * implement this interface and then register it with either the 
 * {@link Unmarshaller#setEventHandler(ValidationEventHandler) Unmarshaller}, 
 * the {@link Validator#setEventHandler(ValidationEventHandler) Validator}, or 
 * the {@link Marshaller#setEventHandler(ValidationEventHandler) Marshaller}.  
 * The JAXB Provider will then report validation errors and warnings encountered
 * during the unmarshal, marshal, and validate operations to these event 
 * handlers.
 *
 * <p>
 * If the {@code handleEvent} method throws an unchecked runtime exception,
 * the JAXB Provider must treat that as if the method returned false, effectively
 * terminating whatever operation was in progress at the time (unmarshal, 
 * validate, or marshal).
 * 
 * <p>
 * Modifying the Java content tree within your event handler is undefined
 * by the specification and may result in unexpected behaviour.
 *
 * <p>
 * Failing to return false from the {@code handleEvent} method after
 * encountering a fatal error is undefined by the specification and may result 
 * in unexpected behavior.
 *
 * <p>
 * <b>Default Event Handler</b>
 * <blockquote>
 *    See: <a href="Validator.html#defaulthandler">Validator javadocs</a>
 * </blockquote>
 *
 * @author <ul><li>Ryan Shoemaker, Sun Microsystems, Inc.</li>
 *             <li>Kohsuke Kawaguchi, Sun Microsystems, Inc.</li>
 *             <li>Joe Fialli, Sun Microsystems, Inc.</li></ul>
 * @see Unmarshaller
 * @see Validator
 * @see Marshaller
 * @see ValidationEvent
 * @see javax.xml.bind.util.ValidationEventCollector
 * @since 1.6, JAXB 1.0
 */
public interface ValidationEventHandler {
    
Receive notification of a validation warning or error. The ValidationEvent will have a ValidationEventLocator embedded in it that indicates where the error or warning occurred. 

If an unchecked runtime exception is thrown from this method, the JAXB
provider will treat it as if the method returned false and interrupt
the current unmarshal, validate, or marshal operation.
Params:
event – the encapsulated validation event information.  It is a 
provider error if this parameter is null.
Throws:
IllegalArgumentException – if the event object is null.
Returns:
true if the JAXB Provider should attempt to continue the current unmarshal, validate, or marshal operation after handling this warning/error, false if the provider should terminate the current operation with the appropriate UnmarshalException, ValidationException, or MarshalException./**
     * Receive notification of a validation warning or error.  
     * 
     * The ValidationEvent will have a 
     * {@link ValidationEventLocator ValidationEventLocator} embedded in it that 
     * indicates where the error or warning occurred.
     *
     * <p>
     * If an unchecked runtime exception is thrown from this method, the JAXB
     * provider will treat it as if the method returned false and interrupt
     * the current unmarshal, validate, or marshal operation.
     * 
     * @param event the encapsulated validation event information.  It is a 
     * provider error if this parameter is null.
     * @return true if the JAXB Provider should attempt to continue the current
     *         unmarshal, validate, or marshal operation after handling this 
     *         warning/error, false if the provider should terminate the current 
     *         operation with the appropriate {@code UnmarshalException},
     *         {@code ValidationException}, or {@code MarshalException}.
     * @throws IllegalArgumentException if the event object is null.
     */
    public boolean handleEvent( ValidationEvent event );
    
}