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
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package javax.xml.bind.annotation;
  27 
  28 import javax.xml.bind.ValidationEventHandler;
  29 import javax.xml.transform.Result;
  30 import 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 JAXB2.0
  53  */
  54 public 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 }