1/*
2 * Copyright (c) 2005, 2013, 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
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24 */
25
26package javax.xml.bind.annotation;
27
28import javax.xml.bind.ValidationEventHandler;
29import javax.xml.transform.Result;
30import javax.xml.transform.Source;
31
32/**
33 * Converts an element (and its descendants)
34 * from/to DOM (or similar) representation.
35 *
36 * <p>
37 * Implementations of this interface will be used in conjunction with
38 * {@link XmlAnyElement} annotation to map an element of XML into a representation
39 * of infoset such as W3C DOM.
40 *
41 * <p>
42 * Implementations hide how a portion of XML is converted into/from such
43 * DOM-like representation, allowing JAXB providers to work with arbitrary
44 * such library.
45 *
46 * <P>
47 * This interface is intended to be implemented by library writers
48 * and consumed by JAXB providers. None of those methods are intended to
49 * be called from applications.
50 *
51 * @author Kohsuke Kawaguchi
52 * @since 1.6, JAXB 2.0
53 */
54public interface DomHandler<ElementT,ResultT extends Result> {
55    /**
56     * When a JAXB provider needs to unmarshal a part of a document into an
57     * infoset representation, it first calls this method to create a
58     * {@link Result} object.
59     *
60     * <p>
61     * A JAXB provider will then send a portion of the XML
62     * into the given result. Such a portion always form a subtree
63     * of the whole XML document rooted at an element.
64     *
65     * @param errorHandler
66     *      if any error happens between the invocation of this method
67     *      and the invocation of {@link #getElement(Result)}, they
68     *      must be reported to this handler.
69     *
70     *      The caller must provide a non-null error handler.
71     *
72     *      The {@link Result} object created from this method
73     *      may hold a reference to this error handler.
74     *
75     * @return
76     *      null if the operation fails. The error must have been reported
77     *      to the error handler.
78     */
79    ResultT createUnmarshaller( ValidationEventHandler errorHandler );
80
81    /**
82     * Once the portion is sent to the {@link Result}. This method is called
83     * by a JAXB provider to obtain the unmarshalled element representation.
84     *
85     * <p>
86     * Multiple invocations of this method may return different objects.
87     * This method can be invoked only when the whole sub-tree are fed
88     * to the {@link Result} object.
89     *
90     * @param rt
91     *      The {@link Result} object created by {@link #createUnmarshaller(ValidationEventHandler)}.
92     *
93     * @return
94     *      null if the operation fails. The error must have been reported
95     *      to the error handler.
96     */
97    ElementT getElement(ResultT rt);
98
99    /**
100     * This method is called when a JAXB provider needs to marshal an element
101     * to XML.
102     *
103     * <p>
104     * If non-null, the returned {@link Source} must contain a whole document
105     * rooted at one element, which will then be weaved into a bigger document
106     * that the JAXB provider is marshalling.
107     *
108     * @param errorHandler
109     *      Receives any errors happened during the process of converting
110     *      an element into a {@link Source}.
111     *
112     *      The caller must provide a non-null error handler.
113     *
114     * @return
115     *      null if there was an error. The error should have been reported
116     *      to the handler.
117     */
118    Source marshal( ElementT n, ValidationEventHandler errorHandler );
119}
120