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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   */
25  
26  package com.sun.xml.internal.bind.v2.runtime.output;
27  
28  import java.io.IOException;
29  
30  import javax.xml.bind.JAXBContext;
31  import javax.xml.stream.XMLStreamException;
32  
33  import com.sun.xml.internal.bind.v2.runtime.Name;
34  import com.sun.xml.internal.bind.v2.runtime.NameList;
35  import com.sun.xml.internal.bind.v2.runtime.XMLSerializer;
36  
37  import org.xml.sax.SAXException;
38  
39  /**
40   * Well-formed XML writer.
41   *
42   * <p>
43   * Implementations of this interface is used to connect {@link XMLSerializer}
44   * to the actual target. This allows {@link XMLSerializer} to be API agnostic.
45   *
46   *
47   * <h2>Notes</h2>
48   * <p>
49   * {@link JAXBContext} assigns indices to URIs and local names
50   * that are statically known by using {@link NameList}.
51   * {@link XmlOutput} implementation can use these indices to improve
52   * the performance. For example, those namespace URI indices can be
53   * turned into prefixes quickly.
54   *
55   * <p>
56   * {@link XmlOutput} still allows arbitrary namepsace URIs / local names
57   * to be written.
58   *
59   * <p>
60   * The {@link NamespaceContextImpl} object, which is shared between {@link XmlOutput} and
61   * {@link XMLSerializer}, keeps track of the in-scope namespace bindings. By the time
62   * the {@link #beginStartTag} method is called, all the namespace bindings for the new
63   * element is already declared. Similarly, after the {@link #endTag} method is called,
64   * in-scope bindings will be removed. This book keeping is all done outside {@link XmlOutput}.
65   *
66   * <p>
67   * {@link XmlOutput} and {@link XMLSerializer} uses indices to
68   * reference prefixes/URIs to be written. {@link NamespaceContextImpl} can
69   * convert prefix indices to URIs and the string representations of prefixes.
70   * Binding from indices to URIs and prefixes do not change while indices
71   * are "in scope", so {@link XmlOutput} is again expected to take advantage of
72   * this to improve the perofmrnace.
73   *
74   * <p>
75   * prefix index 0 is reserved for "xml", and this binding is assumed to be always there.
76   * {@link NamespaceContextImpl} can handle this index correctly, but this binding will never
77   * be reported to {@link XmlOutput} through {@link #beginStartTag}.
78   *
79   * <p>
80   * One pecurilar behavior of a {@link NamespaceContextImpl} object is that it tries
81   * to define redundant xmlns="" on the root element. Implementations of {@link XmlOutput}
82   * is encouraged to check for this and avoid generating redundant namespace declarations.
83   *
84   *
85   *
86   * <h2>Call Sequence</h2>
87   * <p>
88   * {@link XMLSerializer} calls the writer methods in the following order:
89   *
90   * <pre>
91   * CALLSEQUENCE  :=  {@link #startDocument startDocument} ELEMENT {@link #endDocument endDocument}
92   *               |   ELEMENT   // for fragment
93   *
94   * ELEMENT       :=  {@link #beginStartTag beginStartTag} {@link #attribute attribute}* {@link #endStartTag endStartTag} CONTENTS {@link #endTag endTag}
95   *
96   * CONTENTS      :=  (ELEMENT | {@link #text text})*
97   * </pre>
98   *
99   * TODO: for FI, consider making attribute values from Strings to CharSequences.
100  *
101  * @author Kohsuke Kawaguchi
102  */
103 public interface XmlOutput {
104 //
105 //
106 // Contracts
107 //
108 //
109     /**
110      * Called at the very beginning.
111      *
112      * @param serializer
113      *      the {@link XMLSerializer} that coordinates this whole marshalling episode.
114      * @param fragment
115      *      true if we are marshalling a fragment.
116      */
117     public void startDocument(XMLSerializer serializer, boolean fragment, int[] nsUriIndex2prefixIndex, NamespaceContextImpl nsContext) throws IOException, SAXException, XMLStreamException;
118 
119     /**
120      * Called at the very end. This is the last method to be invoked.
121      *
122      * @param fragment
123      *      false if we are writing the whole document.
124      */
125     public void endDocument(boolean fragment) throws IOException, SAXException, XMLStreamException;
126 
127     /**
128      * Writes a start tag.
129      *
130      * <p>
131      * At this point {@link NamespaceContextImpl} holds namespace declarations needed for this
132      * new element.
133      *
134      * <p>
135      * This method is used for writing tags that are indexed.
136      */
137     public void beginStartTag(Name name) throws IOException, XMLStreamException;
138 
139     public void beginStartTag(int prefix, String localName) throws IOException, XMLStreamException;
140 
141     public void attribute( Name name, String value ) throws IOException, XMLStreamException;
142 
143     /**
144      * @param prefix
145      *      -1 if this attribute does not have a prefix
146      *      (this handling differs from that of elements.)
147      */
148     public void attribute( int prefix, String localName, String value ) throws IOException, XMLStreamException;
149 
150     public void endStartTag() throws IOException, SAXException;
151 
152     public void endTag(Name name) throws IOException, SAXException, XMLStreamException;
153 
154     public void endTag(int prefix, String localName) throws IOException, SAXException, XMLStreamException;
155 
156     /**
157      * Writes XML text with character escaping, if necessary.
158      *
159      * @param value
160      *      this string can contain characters that might need escaping
161      *      (such as '&amp;' or '>')
162      * @param needsSeparatingWhitespace
163      */
164     public void text( String value, boolean needsSeparatingWhitespace ) throws IOException, SAXException, XMLStreamException;
165 
166     /**
167      * Writes XML text with character escaping, if necessary.
168      *
169      * @param value
170      *      this string can contain characters that might need escaping
171      *      (such as '&amp;' or '>')
172      * @param needsSeparatingWhitespace
173      */
174     public void text( Pcdata value, boolean needsSeparatingWhitespace ) throws IOException, SAXException, XMLStreamException;
175 }