https://github.com/eclipse-ee4j/jaxb-api/jakarta.xml.bind-api: Jakarta XML Binding API (Eclipse Foundation)
  • Roman Grigoriadi (Oracle Corporation) 
/*
 * Copyright (c) 2005, 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.annotation;

import javax.xml.bind.ValidationEventHandler;
import javax.xml.transform.Result;
import javax.xml.transform.Source;


Converts an element (and its descendants)
from/to DOM (or similar) representation.

 Implementations of this interface will be used in conjunction with XmlAnyElement annotation to map an element of XML into a representation of infoset such as W3C DOM. 

Implementations hide how a portion of XML is converted into/from such
DOM-like representation, allowing JAXB providers to work with arbitrary
such library.


This interface is intended to be implemented by library writers
and consumed by JAXB providers. None of those methods are intended to
be called from applications.

Author:Kohsuke Kawaguchi
Since:1.6, JAXB 2.0
/**
 * Converts an element (and its descendants)
 * from/to DOM (or similar) representation.
 *
 * <p>
 * Implementations of this interface will be used in conjunction with
 * {@link XmlAnyElement} annotation to map an element of XML into a representation
 * of infoset such as W3C DOM.
 *
 * <p>
 * Implementations hide how a portion of XML is converted into/from such
 * DOM-like representation, allowing JAXB providers to work with arbitrary
 * such library.
 *
 * <P>
 * This interface is intended to be implemented by library writers
 * and consumed by JAXB providers. None of those methods are intended to
 * be called from applications.
 *
 * @author Kohsuke Kawaguchi
 * @since 1.6, JAXB 2.0
 */
public interface DomHandler<ElementT,ResultT extends Result> {
    
When a JAXB provider needs to unmarshal a part of a document into an infoset representation, it first calls this method to create a Result object. 

A JAXB provider will then send a portion of the XML
into the given result. Such a portion always form a subtree
of the whole XML document rooted at an element.

Params:
  • errorHandler –  if any error happens between the invocation of this method and the invocation of getElement(Result), they must be reported to this handler. The caller must provide a non-null error handler. The Result object created from this method may hold a reference to this error handler.
Returns:
     null if the operation fails. The error must have been reported
     to the error handler.
/**
     * When a JAXB provider needs to unmarshal a part of a document into an
     * infoset representation, it first calls this method to create a
     * {@link Result} object.
     *
     * <p>
     * A JAXB provider will then send a portion of the XML
     * into the given result. Such a portion always form a subtree
     * of the whole XML document rooted at an element.
     *
     * @param errorHandler
     *      if any error happens between the invocation of this method
     *      and the invocation of {@link #getElement(Result)}, they
     *      must be reported to this handler.
     *
     *      The caller must provide a non-null error handler.
     *
     *      The {@link Result} object created from this method
     *      may hold a reference to this error handler.
     *
     * @return
     *      null if the operation fails. The error must have been reported
     *      to the error handler.
     */
    ResultT createUnmarshaller( ValidationEventHandler errorHandler );

    
Once the portion is sent to the Result. This method is called by a JAXB provider to obtain the unmarshalled element representation. 
 Multiple invocations of this method may return different objects. This method can be invoked only when the whole sub-tree are fed to the Result object. 
Params:
Returns:
     null if the operation fails. The error must have been reported
     to the error handler.
/**
     * Once the portion is sent to the {@link Result}. This method is called
     * by a JAXB provider to obtain the unmarshalled element representation.
     *
     * <p>
     * Multiple invocations of this method may return different objects.
     * This method can be invoked only when the whole sub-tree are fed
     * to the {@link Result} object.
     *
     * @param rt
     *      The {@link Result} object created by {@link #createUnmarshaller(ValidationEventHandler)}.
     *
     * @return
     *      null if the operation fails. The error must have been reported
     *      to the error handler.
     */
    ElementT getElement(ResultT rt);

    
This method is called when a JAXB provider needs to marshal an element
to XML.

 If non-null, the returned Source must contain a whole document rooted at one element, which will then be weaved into a bigger document that the JAXB provider is marshalling. 
Params:
  • errorHandler –  Receives any errors happened during the process of converting an element into a Source. The caller must provide a non-null error handler.
Returns:
     null if there was an error. The error should have been reported
     to the handler.
/**
     * This method is called when a JAXB provider needs to marshal an element
     * to XML.
     *
     * <p>
     * If non-null, the returned {@link Source} must contain a whole document
     * rooted at one element, which will then be weaved into a bigger document
     * that the JAXB provider is marshalling.
     *
     * @param errorHandler
     *      Receives any errors happened during the process of converting
     *      an element into a {@link Source}.
     *
     *      The caller must provide a non-null error handler.
     *
     * @return
     *      null if there was an error. The error should have been reported
     *      to the handler.
     */
    Source marshal( ElementT n, ValidationEventHandler errorHandler );
}