1 /*
2 * Copyright (c) 1997, 2012, 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 '&' 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 '&' or '>')
172 * @param needsSeparatingWhitespace
173 */
174 public void text( Pcdata value, boolean needsSeparatingWhitespace ) throws IOException, SAXException, XMLStreamException;
175 }