1 /*
2 * Copyright 1998-2003 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25
26 package javax.swing.text.html.parser;
27
28 import javax.swing.text.SimpleAttributeSet;
29 import javax.swing.text.html.HTMLEditorKit;
30 import javax.swing.text.html.HTML;
31 import javax.swing.text.ChangedCharSetException;
32
33 import java.util;
34 import java.io;
35 import java.net;
36
37 /**
38 * A Parser for HTML Documents (actually, you can specify a DTD, but
39 * you should really only use this class with the html dtd in swing).
40 * Reads an InputStream of HTML and
41 * invokes the appropriate methods in the ParserCallback class. This
42 * is the default parser used by HTMLEditorKit to parse HTML url's.
43 * <p>This will message the callback for all valid tags, as well as
44 * tags that are implied but not explicitly specified. For example, the
45 * html string (<p>blah) only has a p tag defined. The callback
46 * will see the following methods:
47 * <ol><li><i>handleStartTag(html, ...)</i></li>
48 * <li><i>handleStartTag(head, ...)</i></li>
49 * <li><i>handleEndTag(head)</i></li>
50 * <li><i>handleStartTag(body, ...)</i></li>
51 * <li>handleStartTag(p, ...)</i></li>
52 * <li>handleText(...)</li>
53 * <li><i>handleEndTag(p)</i></li>
54 * <li><i>handleEndTag(body)</i></li>
55 * <li><i>handleEndTag(html)</i></li>
56 * </ol>
57 * The items in <i>italic</i> are implied, that is, although they were not
58 * explicitly specified, to be correct html they should have been present
59 * (head isn't necessary, but it is still generated). For tags that
60 * are implied, the AttributeSet argument will have a value of
61 * <code>Boolean.TRUE</code> for the key
62 * <code>HTMLEditorKit.ParserCallback.IMPLIED</code>.
63 * <p>HTML.Attributes defines a type safe enumeration of html attributes.
64 * If an attribute key of a tag is defined in HTML.Attribute, the
65 * HTML.Attribute will be used as the key, otherwise a String will be used.
66 * For example <p foo=bar class=neat> has two attributes. foo is
67 * not defined in HTML.Attribute, where as class is, therefore the
68 * AttributeSet will have two values in it, HTML.Attribute.CLASS with
69 * a String value of 'neat' and the String key 'foo' with a String value of
70 * 'bar'.
71 * <p>The position argument will indicate the start of the tag, comment
72 * or text. Similiar to arrays, the first character in the stream has a
73 * position of 0. For tags that are
74 * implied the position will indicate
75 * the location of the next encountered tag. In the first example,
76 * the implied start body and html tags will have the same position as the
77 * p tag, and the implied end p, html and body tags will all have the same
78 * position.
79 * <p>As html skips whitespace the position for text will be the position
80 * of the first valid character, eg in the string '\n\n\nblah'
81 * the text 'blah' will have a position of 3, the newlines are skipped.
82 * <p>
83 * For attributes that do not have a value, eg in the html
84 * string <code><foo blah></code> the attribute <code>blah</code>
85 * does not have a value, there are two possible values that will be
86 * placed in the AttributeSet's value:
87 * <ul>
88 * <li>If the DTD does not contain an definition for the element, or the
89 * definition does not have an explicit value then the value in the
90 * AttributeSet will be <code>HTML.NULL_ATTRIBUTE_VALUE</code>.
91 * <li>If the DTD contains an explicit value, as in:
92 * <code><!ATTLIST OPTION selected (selected) #IMPLIED></code>
93 * this value from the dtd (in this case selected) will be used.
94 * </ul>
95 * <p>
96 * Once the stream has been parsed, the callback is notified of the most
97 * likely end of line string. The end of line string will be one of
98 * \n, \r or \r\n, which ever is encountered the most in parsing the
99 * stream.
100 *
101 * @author Sunita Mani
102 */
103 public class DocumentParser extends javax.swing.text.html.parser.Parser {
104
105 private int inbody;
106 private int intitle;
107 private int inhead;
108 private int instyle;
109 private int inscript;
110 private boolean seentitle;
111 private HTMLEditorKit.ParserCallback callback = null;
112 private boolean ignoreCharSet = false;
113 private static final boolean debugFlag = false;
114
115 public DocumentParser(DTD dtd) {
116 super(dtd);
117 }
118
119 public void parse(Reader in, HTMLEditorKit.ParserCallback callback, boolean ignoreCharSet) throws IOException {
120 this.ignoreCharSet = ignoreCharSet;
121 this.callback = callback;
122 parse(in);
123 // end of line
124 callback.handleEndOfLineString(getEndOfLineString());
125 }
126
127 /**
128 * Handle Start Tag.
129 */
130 protected void handleStartTag(TagElement tag) {
131
132 Element elem = tag.getElement();
133 if (elem == dtd.body) {
134 inbody++;
135 } else if (elem == dtd.html) {
136 } else if (elem == dtd.head) {
137 inhead++;
138 } else if (elem == dtd.title) {
139 intitle++;
140 } else if (elem == dtd.style) {
141 instyle++;
142 } else if (elem == dtd.script) {
143 inscript++;
144 }
145 if (debugFlag) {
146 if (tag.fictional()) {
147 debug("Start Tag: " + tag.getHTMLTag() + " pos: " + getCurrentPos());
148 } else {
149 debug("Start Tag: " + tag.getHTMLTag() + " attributes: " +
150 getAttributes() + " pos: " + getCurrentPos());
151 }
152 }
153 if (tag.fictional()) {
154 SimpleAttributeSet attrs = new SimpleAttributeSet();
155 attrs.addAttribute(HTMLEditorKit.ParserCallback.IMPLIED,
156 Boolean.TRUE);
157 callback.handleStartTag(tag.getHTMLTag(), attrs,
158 getBlockStartPosition());
159 } else {
160 callback.handleStartTag(tag.getHTMLTag(), getAttributes(),
161 getBlockStartPosition());
162 flushAttributes();
163 }
164 }
165
166
167 protected void handleComment(char text[]) {
168 if (debugFlag) {
169 debug("comment: ->" + new String(text) + "<-"
170 + " pos: " + getCurrentPos());
171 }
172 callback.handleComment(text, getBlockStartPosition());
173 }
174
175 /**
176 * Handle Empty Tag.
177 */
178 protected void handleEmptyTag(TagElement tag) throws ChangedCharSetException {
179
180 Element elem = tag.getElement();
181 if (elem == dtd.meta && !ignoreCharSet) {
182 SimpleAttributeSet atts = getAttributes();
183 if (atts != null) {
184 String content = (String)atts.getAttribute(HTML.Attribute.CONTENT);
185 if (content != null) {
186 if ("content-type".equalsIgnoreCase((String)atts.getAttribute(HTML.Attribute.HTTPEQUIV))) {
187 if (!content.equalsIgnoreCase("text/html") &&
188 !content.equalsIgnoreCase("text/plain")) {
189 throw new ChangedCharSetException(content, false);
190 }
191 } else if ("charset" .equalsIgnoreCase((String)atts.getAttribute(HTML.Attribute.HTTPEQUIV))) {
192 throw new ChangedCharSetException(content, true);
193 }
194 }
195 }
196 }
197 if (inbody != 0 || elem == dtd.meta || elem == dtd.base || elem == dtd.isindex || elem == dtd.style || elem == dtd.link) {
198 if (debugFlag) {
199 if (tag.fictional()) {
200 debug("Empty Tag: " + tag.getHTMLTag() + " pos: " + getCurrentPos());
201 } else {
202 debug("Empty Tag: " + tag.getHTMLTag() + " attributes: "
203 + getAttributes() + " pos: " + getCurrentPos());
204 }
205 }
206 if (tag.fictional()) {
207 SimpleAttributeSet attrs = new SimpleAttributeSet();
208 attrs.addAttribute(HTMLEditorKit.ParserCallback.IMPLIED,
209 Boolean.TRUE);
210 callback.handleSimpleTag(tag.getHTMLTag(), attrs,
211 getBlockStartPosition());
212 } else {
213 callback.handleSimpleTag(tag.getHTMLTag(), getAttributes(),
214 getBlockStartPosition());
215 flushAttributes();
216 }
217 }
218 }
219
220 /**
221 * Handle End Tag.
222 */
223 protected void handleEndTag(TagElement tag) {
224 Element elem = tag.getElement();
225 if (elem == dtd.body) {
226 inbody--;
227 } else if (elem == dtd.title) {
228 intitle--;
229 seentitle = true;
230 } else if (elem == dtd.head) {
231 inhead--;
232 } else if (elem == dtd.style) {
233 instyle--;
234 } else if (elem == dtd.script) {
235 inscript--;
236 }
237 if (debugFlag) {
238 debug("End Tag: " + tag.getHTMLTag() + " pos: " + getCurrentPos());
239 }
240 callback.handleEndTag(tag.getHTMLTag(), getBlockStartPosition());
241
242 }
243
244 /**
245 * Handle Text.
246 */
247 protected void handleText(char data[]) {
248 if (data != null) {
249 if (inscript != 0) {
250 callback.handleComment(data, getBlockStartPosition());
251 return;
252 }
253 if (inbody != 0 || ((instyle != 0) ||
254 ((intitle != 0) && !seentitle))) {
255 if (debugFlag) {
256 debug("text: ->" + new String(data) + "<-" + " pos: " + getCurrentPos());
257 }
258 callback.handleText(data, getBlockStartPosition());
259 }
260 }
261 }
262
263 /*
264 * Error handling.
265 */
266 protected void handleError(int ln, String errorMsg) {
267 if (debugFlag) {
268 debug("Error: ->" + errorMsg + "<-" + " pos: " + getCurrentPos());
269 }
270 /* PENDING: need to improve the error string. */
271 callback.handleError(errorMsg, getCurrentPos());
272 }
273
274
275 /*
276 * debug messages
277 */
278 private void debug(String msg) {
279 System.out.println(msg);
280 }
281 }
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