jdk8-mips64-public/jaxws: src/share/jaxws_classes/com/sun/xml/internal/bind/v2/runtime/unmarshaller/XmlVisitor.java@e530533619ec

     1 /*

     2  * Copyright (c) 1997, 2011, 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  */

    26 package com.sun.xml.internal.bind.v2.runtime.unmarshaller;

    28 import javax.xml.namespace.NamespaceContext;

    30 import org.xml.sax.SAXException;

    32 /**

    33  * Walks the XML document structure.

    34  *

    35  * Implemented by the unmarshaller and called by the API-specific connectors.

    36  *

    37  * <h2>Event Call Sequence</h2>

    38  *

    39  * The {@link XmlVisitor} expects the event callbacks in the following order:

    40  * <pre>

    41  * CALL SEQUENCE := startDocument ELEMENT endDocument

    42  * ELEMENT       := startPrefixMapping ELEMENT endPrefixMapping

    43  *               |  startElement BODY endElement

    44  * BODY          := text? (ELEMENT text?)*

    45  * </pre>

    46  * Note in particular that text events may not be called in a row;

    47  * consecutive characters (even those separated by PIs and comments)

    48  * must be reported as one event, unlike SAX.

    49  *

    50  * <p>

    51  * All namespace URIs, local names, and prefixes of element and attribute

    52  * names must be interned. qnames need not be interned.

    53  *

    54  *

    55  * <h2>Typed PCDATA</h2>

    56  * For efficiency, JAXB RI defines a few {@link CharSequence} implementations

    57  * that can be used as a parameter to the {@link #text(CharSequence)} method.

    58  * For example, see {@link Base64Data}.

    59  *

    60  * <h2>Error Handling</h2>

    61  * The visitor may throw {@link SAXException} to abort the unmarshalling process

    62  * in the middle.

    63  *

    64  * @author Kohsuke Kawaguchi

    65  */

    66 public interface XmlVisitor {

    67     /**

    68      * Notifies a start of the document.

    69      *

    70      * @param locator

    71      *      This live object returns the location information as the parsing progresses.

    72      *      must not be null.

    73      * @param nsContext

    74      *      Some broken XML APIs can't iterate all the in-scope namespace bindings,

    75      *      which makes it impossible to emulate {@link #startPrefixMapping(String, String)} correctly

    76      *      when unmarshalling a subtree. Connectors that use such an API can

    77      *      pass in additional {@link NamespaceContext} object that knows about the

    78      *      in-scope namespace bindings. Otherwise (and normally) it is null.

    79      *

    80      *      <p>

    81      *      Ideally this object should be immutable and only represent the namespace URI bindings

    82      *      in the context (those done above the element that JAXB started unmarshalling),

    83      *      but it can also work even if it changes as the parsing progress (to include

    84      *      namespaces declared on the current element being parsed.)

    85      */

    86     void startDocument(LocatorEx locator, NamespaceContext nsContext) throws SAXException;

    87     void endDocument() throws SAXException;

    89     /**

    90      * Notifies a start tag of a new element.

    91      *

    92      * namespace URIs and local names must be interned.

    93      */

    94     void startElement(TagName tagName) throws SAXException;

    95     void endElement(TagName tagName) throws SAXException;

    97     /**

    98      * Called before {@link #startElement} event to notify a new namespace binding.

    99      */

   100     void startPrefixMapping( String prefix, String nsUri ) throws SAXException;

   101     /**

   102      * Called after {@link #endElement} event to notify the end of a binding.

   103      */

   104     void endPrefixMapping( String prefix ) throws SAXException;

   106     /**

   107      * Text events.

   108      *

   109      * <p>

   110      * The caller should consult {@link TextPredictor} to see

   111      * if the unmarshaller is expecting any PCDATA. If the above is returning

   112      * false, the caller is OK to skip any text in XML. The net effect is

   113      * that we can ignore whitespaces quickly.

   114      *

   115      * @param pcdata

   116      *      represents character data. This object can be mutable

   117      *      (such as {@link StringBuilder}); it only needs to be fixed

   118      *      while this method is executing.

   119      */

   120     void text( CharSequence pcdata ) throws SAXException;

   122     /**

   123      * Returns the {@link UnmarshallingContext} at the end of the chain.

   124      *

   125      * @return

   126      *      always return the same object, so caching the result is recommended.

   127      */

   128     UnmarshallingContext getContext();

   130     /**

   131      * Gets the predictor that can be used for the caller to avoid

   132      * calling {@link #text(CharSequence)} unnecessarily.

   133      */

   134     TextPredictor getPredictor();

   136     interface TextPredictor {

   137         /**

   138          * Returns true if the visitor is expecting a text event as the next event.

   139          *

   140          * <p>

   141          * This is primarily intended to be used for optimization to avoid buffering

   142          * characters unnecessarily. If this method returns false and the connector

   143          * sees whitespace it can safely skip it.

   144          *

   145          * <p>

   146          * If this method returns true, all the whitespaces are considered significant

   147          * and thus need to be reported as a {@link XmlVisitor#text} event. Furthermore,

   148          * if the element has no children (like &lt;foo/>), then it has to be reported

   149          * an empty {@link XmlVisitor#text} event.

   150          */

   151         boolean expectText();

   152     }

   153 }

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