1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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15 * accompanied this code).
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24 */
25 package javax.swing.text;
26
27 import javax.swing.event.*;
28
29 /**
30 * <p>
31 * The <code>Document</code> is a container for text that serves
32 * as the model for swing text components. The goal for this
33 * interface is to scale from very simple needs (a plain text textfield)
34 * to complex needs (an HTML or XML document, for example).
35 *
36 * <p><b>Content</b>
37 * <p>
38 * At the simplest level, text can be
39 * modeled as a linear sequence of characters. To support
40 * internationalization, the Swing text model uses
41 * <a href="http://www.unicode.org/">unicode</a> characters.
42 * The sequence of characters displayed in a text component is
43 * generally referred to as the component's <em>content</em>.
44 * <p>
45 * To refer to locations within the sequence, the coordinates
46 * used are the location between two characters. As the diagram
47 * below shows, a location in a text document can be referred to
48 * as a position, or an offset. This position is zero-based.
49 * <p style="text-align:center"><img src="doc-files/Document-coord.gif"
50 * alt="The following text describes this graphic.">
51 * <p>
52 * In the example, if the content of a document is the
53 * sequence "The quick brown fox," as shown in the preceding diagram,
54 * the location just before the word "The" is 0, and the location after
55 * the word "The" and before the whitespace that follows it is 3.
56 * The entire sequence of characters in the sequence "The" is called a
57 * <em>range</em>.
58 * <p>The following methods give access to the character data
59 * that makes up the content.
60 * <ul>
61 * <li>{@link #getLength()}
62 * <li>{@link #getText(int, int)}
63 * <li>{@link #getText(int, int, javax.swing.text.Segment)}
64 * </ul>
65 * <p><b>Structure</b>
66 * <p>
67 * Text is rarely represented simply as featureless content. Rather,
68 * text typically has some sort of structure associated with it.
69 * Exactly what structure is modeled is up to a particular Document
70 * implementation. It might be as simple as no structure (i.e. a
71 * simple text field), or it might be something like diagram below.
72 * <p style="text-align:center"><img src="doc-files/Document-structure.gif"
73 * alt="Diagram shows Book->Chapter->Paragraph">
74 * <p>
75 * The unit of structure (i.e. a node of the tree) is referred to
76 * by the <a href="Element.html">Element</a> interface. Each Element
77 * can be tagged with a set of attributes. These attributes
78 * (name/value pairs) are defined by the
79 * <a href="AttributeSet.html">AttributeSet</a> interface.
80 * <p>The following methods give access to the document structure.
81 * <ul>
82 * <li>{@link #getDefaultRootElement()}
83 * <li>{@link #getRootElements()}
84 * </ul>
85 *
86 * <p><b>Mutations</b>
87 * <p>
88 * All documents need to be able to add and remove simple text.
89 * Typically, text is inserted and removed via gestures from
90 * a keyboard or a mouse. What effect the insertion or removal
91 * has upon the document structure is entirely up to the
92 * implementation of the document.
93 * <p>The following methods are related to mutation of the
94 * document content:
95 * <ul>
96 * <li>{@link #insertString(int, java.lang.String, javax.swing.text.AttributeSet)}
97 * <li>{@link #remove(int, int)}
98 * <li>{@link #createPosition(int)}
99 * </ul>
100 *
101 * <p><b>Notification</b>
102 * <p>
103 * Mutations to the <code>Document</code> must be communicated to
104 * interested observers. The notification of change follows the event model
105 * guidelines that are specified for JavaBeans. In the JavaBeans
106 * event model, once an event notification is dispatched, all listeners
107 * must be notified before any further mutations occur to the source
108 * of the event. Further, order of delivery is not guaranteed.
109 * <p>
110 * Notification is provided as two separate events,
111 * <a href="../event/DocumentEvent.html">DocumentEvent</a>, and
112 * <a href="../event/UndoableEditEvent.html">UndoableEditEvent</a>.
113 * If a mutation is made to a <code>Document</code> through its api,
114 * a <code>DocumentEvent</code> will be sent to all of the registered
115 * <code>DocumentListeners</code>. If the <code>Document</code>
116 * implementation supports undo/redo capabilities, an
117 * <code>UndoableEditEvent</code> will be sent
118 * to all of the registered <code>UndoableEditListener</code>s.
119 * If an undoable edit is undone, a <code>DocumentEvent</code> should be
120 * fired from the Document to indicate it has changed again.
121 * In this case however, there should be no <code>UndoableEditEvent</code>
122 * generated since that edit is actually the source of the change
123 * rather than a mutation to the <code>Document</code> made through its
124 * api.
125 * <p style="text-align:center"><img src="doc-files/Document-notification.gif"
126 * alt="The preceding text describes this graphic.">
127 * <p>
128 * Referring to the above diagram, suppose that the component shown
129 * on the left mutates the document object represented by the blue
130 * rectangle. The document responds by dispatching a DocumentEvent to
131 * both component views and sends an UndoableEditEvent to the listening
132 * logic, which maintains a history buffer.
133 * <p>
134 * Now suppose that the component shown on the right mutates the same
135 * document. Again, the document dispatches a DocumentEvent to both
136 * component views and sends an UndoableEditEvent to the listening logic
137 * that is maintaining the history buffer.
138 * <p>
139 * If the history buffer is then rolled back (i.e. the last UndoableEdit
140 * undone), a DocumentEvent is sent to both views, causing both of them to
141 * reflect the undone mutation to the document (that is, the
142 * removal of the right component's mutation). If the history buffer again
143 * rolls back another change, another DocumentEvent is sent to both views,
144 * causing them to reflect the undone mutation to the document -- that is,
145 * the removal of the left component's mutation.
146 * <p>
147 * The methods related to observing mutations to the document are:
148 * <ul>
149 * <li><a href="#addDocumentListener(javax.swing.event.DocumentListener)">addDocumentListener(DocumentListener)</a>
150 * <li><a href="#removeDocumentListener(javax.swing.event.DocumentListener)">removeDocumentListener(DocumentListener)</a>
151 * <li><a href="#addUndoableEditListener(javax.swing.event.UndoableEditListener)">addUndoableEditListener(UndoableEditListener)</a>
152 * <li><a href="#removeUndoableEditListener(javax.swing.event.UndoableEditListener)">removeUndoableEditListener(UndoableEditListener)</a>
153 * </ul>
154 *
155 * <p><b>Properties</b>
156 * <p>
157 * Document implementations will generally have some set of properties
158 * associated with them at runtime. Two well known properties are the
159 * <a href="#StreamDescriptionProperty">StreamDescriptionProperty</a>,
160 * which can be used to describe where the <code>Document</code> came from,
161 * and the <a href="#TitleProperty">TitleProperty</a>, which can be used to
162 * name the <code>Document</code>. The methods related to the properties are:
163 * <ul>
164 * <li>{@link #getProperty(java.lang.Object)}
165 * <li>{@link #putProperty(java.lang.Object, java.lang.Object)}
166 * </ul>
167 *
168 * <p>For more information on the <code>Document</code> class, see
169 * <a href="http://java.sun.com/products/jfc/tsc">The Swing Connection</a>
170 * and most particularly the article,
171 * <a href="http://java.sun.com/products/jfc/tsc/articles/text/element_interface">
172 * The Element Interface</a>.
173 *
174 * @author Timothy Prinzing
175 *
176 * @see javax.swing.event.DocumentEvent
177 * @see javax.swing.event.DocumentListener
178 * @see javax.swing.event.UndoableEditEvent
179 * @see javax.swing.event.UndoableEditListener
180 * @see Element
181 * @see Position
182 * @see AttributeSet
183 */
184 public interface Document {
185
186 /**
187 * Returns number of characters of content currently
188 * in the document.
189 *
190 * @return number of characters >= 0
191 */
192 public int getLength();
193
194 /**
195 * Registers the given observer to begin receiving notifications
196 * when changes are made to the document.
197 *
198 * @param listener the observer to register
199 * @see Document#removeDocumentListener
200 */
201 public void addDocumentListener(DocumentListener listener);
202
203 /**
204 * Unregisters the given observer from the notification list
205 * so it will no longer receive change updates.
206 *
207 * @param listener the observer to register
208 * @see Document#addDocumentListener
209 */
210 public void removeDocumentListener(DocumentListener listener);
211
212 /**
213 * Registers the given observer to begin receiving notifications
214 * when undoable edits are made to the document.
215 *
216 * @param listener the observer to register
217 * @see javax.swing.event.UndoableEditEvent
218 */
219 public void addUndoableEditListener(UndoableEditListener listener);
220
221 /**
222 * Unregisters the given observer from the notification list
223 * so it will no longer receive updates.
224 *
225 * @param listener the observer to register
226 * @see javax.swing.event.UndoableEditEvent
227 */
228 public void removeUndoableEditListener(UndoableEditListener listener);
229
230 /**
231 * Gets the properties associated with the document.
232 *
233 * @param key a non-<code>null</code> property key
234 * @return the properties
235 * @see #putProperty(Object, Object)
236 */
237 public Object getProperty(Object key);
238
239 /**
240 * Associates a property with the document. Two standard
241 * property keys provided are: <a href="#StreamDescriptionProperty">
242 * <code>StreamDescriptionProperty</code></a> and
243 * <a href="#TitleProperty"><code>TitleProperty</code></a>.
244 * Other properties, such as author, may also be defined.
245 *
246 * @param key the non-<code>null</code> property key
247 * @param value the property value
248 * @see #getProperty(Object)
249 */
250 public void putProperty(Object key, Object value);
251
252 /**
253 * Removes a portion of the content of the document.
254 * This will cause a DocumentEvent of type
255 * DocumentEvent.EventType.REMOVE to be sent to the
256 * registered DocumentListeners, unless an exception
257 * is thrown. The notification will be sent to the
258 * listeners by calling the removeUpdate method on the
259 * DocumentListeners.
260 * <p>
261 * To ensure reasonable behavior in the face
262 * of concurrency, the event is dispatched after the
263 * mutation has occurred. This means that by the time a
264 * notification of removal is dispatched, the document
265 * has already been updated and any marks created by
266 * <code>createPosition</code> have already changed.
267 * For a removal, the end of the removal range is collapsed
268 * down to the start of the range, and any marks in the removal
269 * range are collapsed down to the start of the range.
270 * <p style="text-align:center"><img src="doc-files/Document-remove.gif"
271 * alt="Diagram shows removal of 'quick' from 'The quick brown fox.'">
272 * <p>
273 * If the Document structure changed as result of the removal,
274 * the details of what Elements were inserted and removed in
275 * response to the change will also be contained in the generated
276 * DocumentEvent. It is up to the implementation of a Document
277 * to decide how the structure should change in response to a
278 * remove.
279 * <p>
280 * If the Document supports undo/redo, an UndoableEditEvent will
281 * also be generated.
282 *
283 * @param offs the offset from the beginning >= 0
284 * @param len the number of characters to remove >= 0
285 * @exception BadLocationException some portion of the removal range
286 * was not a valid part of the document. The location in the exception
287 * is the first bad position encountered.
288 * @see javax.swing.event.DocumentEvent
289 * @see javax.swing.event.DocumentListener
290 * @see javax.swing.event.UndoableEditEvent
291 * @see javax.swing.event.UndoableEditListener
292 */
293 public void remove(int offs, int len) throws BadLocationException;
294
295 /**
296 * Inserts a string of content. This will cause a DocumentEvent
297 * of type DocumentEvent.EventType.INSERT to be sent to the
298 * registered DocumentListers, unless an exception is thrown.
299 * The DocumentEvent will be delivered by calling the
300 * insertUpdate method on the DocumentListener.
301 * The offset and length of the generated DocumentEvent
302 * will indicate what change was actually made to the Document.
303 * <p style="text-align:center"><img src="doc-files/Document-insert.gif"
304 * alt="Diagram shows insertion of 'quick' in 'The quick brown fox'">
305 * <p>
306 * If the Document structure changed as result of the insertion,
307 * the details of what Elements were inserted and removed in
308 * response to the change will also be contained in the generated
309 * DocumentEvent. It is up to the implementation of a Document
310 * to decide how the structure should change in response to an
311 * insertion.
312 * <p>
313 * If the Document supports undo/redo, an UndoableEditEvent will
314 * also be generated.
315 *
316 * @param offset the offset into the document to insert the content >= 0.
317 * All positions that track change at or after the given location
318 * will move.
319 * @param str the string to insert
320 * @param a the attributes to associate with the inserted
321 * content. This may be null if there are no attributes.
322 * @exception BadLocationException the given insert position is not a valid
323 * position within the document
324 * @see javax.swing.event.DocumentEvent
325 * @see javax.swing.event.DocumentListener
326 * @see javax.swing.event.UndoableEditEvent
327 * @see javax.swing.event.UndoableEditListener
328 */
329 public void insertString(int offset, String str, AttributeSet a) throws BadLocationException;
330
331 /**
332 * Fetches the text contained within the given portion
333 * of the document.
334 *
335 * @param offset the offset into the document representing the desired
336 * start of the text >= 0
337 * @param length the length of the desired string >= 0
338 * @return the text, in a String of length >= 0
339 * @exception BadLocationException some portion of the given range
340 * was not a valid part of the document. The location in the exception
341 * is the first bad position encountered.
342 */
343 public String getText(int offset, int length) throws BadLocationException;
344
345 /**
346 * Fetches the text contained within the given portion
347 * of the document.
348 * <p>
349 * If the partialReturn property on the txt parameter is false, the
350 * data returned in the Segment will be the entire length requested and
351 * may or may not be a copy depending upon how the data was stored.
352 * If the partialReturn property is true, only the amount of text that
353 * can be returned without creating a copy is returned. Using partial
354 * returns will give better performance for situations where large
355 * parts of the document are being scanned. The following is an example
356 * of using the partial return to access the entire document:
357 *
358 * <pre><code>
359 *
360 * int nleft = doc.getDocumentLength();
361 * Segment text = new Segment();
362 * int offs = 0;
363 * text.setPartialReturn(true);
364 * while (nleft > 0) {
365 * doc.getText(offs, nleft, text);
366 * // do someting with text
367 * nleft -= text.count;
368 * offs += text.count;
369 * }
370 *
371 * </code></pre>
372 *
373 * @param offset the offset into the document representing the desired
374 * start of the text >= 0
375 * @param length the length of the desired string >= 0
376 * @param txt the Segment object to return the text in
377 *
378 * @exception BadLocationException Some portion of the given range
379 * was not a valid part of the document. The location in the exception
380 * is the first bad position encountered.
381 */
382 public void getText(int offset, int length, Segment txt) throws BadLocationException;
383
384 /**
385 * Returns a position that represents the start of the document. The
386 * position returned can be counted on to track change and stay
387 * located at the beginning of the document.
388 *
389 * @return the position
390 */
391 public Position getStartPosition();
392
393 /**
394 * Returns a position that represents the end of the document. The
395 * position returned can be counted on to track change and stay
396 * located at the end of the document.
397 *
398 * @return the position
399 */
400 public Position getEndPosition();
401
402 /**
403 * This method allows an application to mark a place in
404 * a sequence of character content. This mark can then be
405 * used to tracks change as insertions and removals are made
406 * in the content. The policy is that insertions always
407 * occur prior to the current position (the most common case)
408 * unless the insertion location is zero, in which case the
409 * insertion is forced to a position that follows the
410 * original position.
411 *
412 * @param offs the offset from the start of the document >= 0
413 * @return the position
414 * @exception BadLocationException if the given position does not
415 * represent a valid location in the associated document
416 */
417 public Position createPosition(int offs) throws BadLocationException;
418
419 /**
420 * Returns all of the root elements that are defined.
421 * <p>
422 * Typically there will be only one document structure, but the interface
423 * supports building an arbitrary number of structural projections over the
424 * text data. The document can have multiple root elements to support
425 * multiple document structures. Some examples might be:
426 * </p>
427 * <ul>
428 * <li>Text direction.
429 * <li>Lexical token streams.
430 * <li>Parse trees.
431 * <li>Conversions to formats other than the native format.
432 * <li>Modification specifications.
433 * <li>Annotations.
434 * </ul>
435 *
436 * @return the root element
437 */
438 public Element[] getRootElements();
439
440 /**
441 * Returns the root element that views should be based upon,
442 * unless some other mechanism for assigning views to element
443 * structures is provided.
444 *
445 * @return the root element
446 */
447 public Element getDefaultRootElement();
448
449 /**
450 * Allows the model to be safely rendered in the presence
451 * of concurrency, if the model supports being updated asynchronously.
452 * The given runnable will be executed in a way that allows it
453 * to safely read the model with no changes while the runnable
454 * is being executed. The runnable itself may <em>not</em>
455 * make any mutations.
456 *
457 * @param r a <code>Runnable</code> used to render the model
458 */
459 public void render(Runnable r);
460
461 /**
462 * The property name for the description of the stream
463 * used to initialize the document. This should be used
464 * if the document was initialized from a stream and
465 * anything is known about the stream.
466 */
467 public static final String StreamDescriptionProperty = "stream";
468
469 /**
470 * The property name for the title of the document, if
471 * there is one.
472 */
473 public static final String TitleProperty = "title";
474
475
476 }