001 /* PrintStream.java -- OutputStream for printing output
002 Copyright (C) 1998, 1999, 2001, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038
039 package java.io;
040
041 import java.util.Formatter;
042 import java.util.Locale;
043
044 import gnu.gcj.convert.UnicodeToBytes;
045
046 /* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
047 * "The Java Language Specification", ISBN 0-201-63451-1
048 * Status: Believed complete and correct to 1.3
049 */
050
051 /**
052 * This class prints Java primitive values and object to a stream as
053 * text. None of the methods in this class throw an exception. However,
054 * errors can be detected by calling the <code>checkError()</code> method.
055 * Additionally, this stream can be designated as "autoflush" when
056 * created so that any writes are automatically flushed to the underlying
057 * output sink when the current line is terminated.
058 * <p>
059 * This class converts char's into byte's using the system default encoding.
060 *
061 * @author Aaron M. Renn (arenn@urbanophile.com)
062 * @author Tom Tromey (tromey@cygnus.com)
063 */
064 public class PrintStream extends FilterOutputStream implements Appendable
065 {
066 /* Notice the implementation is quite similar to OutputStreamWriter.
067 * This leads to some minor duplication, because neither inherits
068 * from the other, and we want to maximize performance. */
069
070 // Line separator string.
071 private static final char[] line_separator
072 = System.getProperty("line.separator").toCharArray();
073
074 UnicodeToBytes converter;
075
076 // Work buffer of characters for converter.
077 char[] work = new char[100];
078 // Work buffer of bytes where we temporarily keep converter output.
079 byte[] work_bytes = new byte[100];
080
081 /**
082 * This boolean indicates whether or not an error has ever occurred
083 * on this stream.
084 */
085 private boolean error_occurred = false;
086
087 /**
088 * This is <code>true</code> if auto-flush is enabled,
089 * <code>false</code> otherwise
090 */
091 private boolean auto_flush;
092
093 /**
094 * This method intializes a new <code>PrintStream</code> object to write
095 * to the specified output sink.
096 *
097 * @param out The <code>OutputStream</code> to write to.
098 */
099 public PrintStream (OutputStream out)
100 {
101 this (out, false);
102 }
103
104 /**
105 * This method intializes a new <code>PrintStream</code> object to write
106 * to the specified output sink. This constructor also allows "auto-flush"
107 * functionality to be specified where the stream will be flushed after
108 * every <code>print</code> or <code>println</code> call, when the
109 * <code>write</code> methods with array arguments are called, or when a
110 * single new-line character is written.
111 * <p>
112 *
113 * @param out The <code>OutputStream</code> to write to.
114 * @param auto_flush <code>true</code> to flush the stream after every
115 * line, <code>false</code> otherwise
116 */
117 public PrintStream (OutputStream out, boolean auto_flush)
118 {
119 super (out);
120
121 converter = UnicodeToBytes.getDefaultEncoder();
122 this.auto_flush = auto_flush;
123 }
124
125 /**
126 * This method initializes a new <code>PrintStream</code> object to write
127 * to the specified output File. Doesn't autoflush.
128 *
129 * @param file The <code>File</code> to write to.
130 * @throws FileNotFoundException if an error occurs while opening the file.
131 *
132 * @since 1.5
133 */
134 public PrintStream (File file)
135 throws FileNotFoundException
136 {
137 this (new FileOutputStream(file), false);
138 }
139
140 /**
141 * This method initializes a new <code>PrintStream</code> object to write
142 * to the specified output File. Doesn't autoflush.
143 *
144 * @param file The <code>File</code> to write to.
145 * @param encoding The name of the character encoding to use for this
146 * object.
147 * @throws FileNotFoundException If an error occurs while opening the file.
148 * @throws UnsupportedEncodingException If the charset specified by
149 * <code>encoding</code> is invalid.
150 *
151 * @since 1.5
152 */
153 public PrintStream (File file, String encoding)
154 throws FileNotFoundException,UnsupportedEncodingException
155 {
156 this (new FileOutputStream(file), false, encoding);
157 }
158
159 /**
160 * This method initializes a new <code>PrintStream</code> object to write
161 * to the specified output File. Doesn't autoflush.
162 *
163 * @param fileName The name of the <code>File</code> to write to.
164 * @throws FileNotFoundException if an error occurs while opening the file,
165 *
166 * @since 1.5
167 */
168 public PrintStream (String fileName)
169 throws FileNotFoundException
170 {
171 this (new FileOutputStream(new File(fileName)), false);
172 }
173
174 /**
175 * This method initializes a new <code>PrintStream</code> object to write
176 * to the specified output File. Doesn't autoflush.
177 *
178 * @param fileName The name of the <code>File</code> to write to.
179 * @param encoding The name of the character encoding to use for this
180 * object.
181 * @throws FileNotFoundException if an error occurs while opening the file.
182 * @throws UnsupportedEncodingException If the charset specified by
183 * <code>encoding</code> is invalid.
184 *
185 * @since 1.5
186 */
187 public PrintStream (String fileName, String encoding)
188 throws FileNotFoundException,UnsupportedEncodingException
189 {
190 this (new FileOutputStream(new File(fileName)), false, encoding);
191 }
192
193 /**
194 * This method intializes a new <code>PrintStream</code> object to write
195 * to the specified output sink. This constructor also allows "auto-flush"
196 * functionality to be specified where the stream will be flushed after
197 * every <code>print</code> or <code>println</code> call, when the
198 * <code>write</code> methods with array arguments are called, or when a
199 * single new-line character is written.
200 * <p>
201 *
202 * @param out The <code>OutputStream</code> to write to.
203 * @param auto_flush <code>true</code> to flush the stream after every
204 * line, <code>false</code> otherwise
205 * @param encoding The name of the character encoding to use for this
206 * object.
207 */
208 public PrintStream (OutputStream out, boolean auto_flush, String encoding)
209 throws UnsupportedEncodingException
210 {
211 super (out);
212
213 converter = UnicodeToBytes.getEncoder (encoding);
214 this.auto_flush = auto_flush;
215 }
216
217 /**
218 * This method checks to see if an error has occurred on this stream. Note
219 * that once an error has occurred, this method will continue to report
220 * <code>true</code> forever for this stream. Before checking for an
221 * error condition, this method flushes the stream.
222 *
223 * @return <code>true</code> if an error has occurred,
224 * <code>false</code> otherwise
225 */
226 public boolean checkError ()
227 {
228 flush ();
229 return error_occurred;
230 }
231
232 /**
233 * This method can be called by subclasses to indicate that an error
234 * has occurred and should be reported by <code>checkError</code>.
235 */
236 protected void setError ()
237 {
238 error_occurred = true;
239 }
240
241 /**
242 * This method closes this stream and all underlying streams.
243 */
244 public void close ()
245 {
246 try
247 {
248 converter.setFinished();
249 writeChars(new char[0], 0, 0);
250 flush();
251 out.close();
252 }
253 catch (InterruptedIOException iioe)
254 {
255 Thread.currentThread().interrupt();
256 }
257 catch (IOException e)
258 {
259 setError ();
260 }
261 }
262
263 /**
264 * This method flushes any buffered bytes to the underlying stream and
265 * then flushes that stream as well.
266 */
267 public void flush ()
268 {
269 try
270 {
271 out.flush();
272 }
273 catch (InterruptedIOException iioe)
274 {
275 Thread.currentThread().interrupt();
276 }
277 catch (IOException e)
278 {
279 setError ();
280 }
281 }
282
283 private synchronized void print (String str, boolean println)
284 {
285 try
286 {
287 writeChars(str, 0, str.length());
288 if (println)
289 writeChars(line_separator, 0, line_separator.length);
290 if (auto_flush)
291 flush();
292 }
293 catch (InterruptedIOException iioe)
294 {
295 Thread.currentThread().interrupt();
296 }
297 catch (IOException e)
298 {
299 setError ();
300 }
301 }
302
303 private synchronized void print (char[] chars, int pos, int len,
304 boolean println)
305 {
306 try
307 {
308 writeChars(chars, pos, len);
309 if (println)
310 writeChars(line_separator, 0, line_separator.length);
311 if (auto_flush)
312 flush();
313 }
314 catch (InterruptedIOException iioe)
315 {
316 Thread.currentThread().interrupt();
317 }
318 catch (IOException e)
319 {
320 setError ();
321 }
322 }
323
324 private void writeChars(char[] buf, int offset, int count)
325 throws IOException
326 {
327 do
328 {
329 converter.setOutput(work_bytes, 0);
330 int converted = converter.write(buf, offset, count);
331 offset += converted;
332 count -= converted;
333 out.write(work_bytes, 0, converter.count);
334 }
335 while (count > 0 || converter.havePendingBytes());
336 }
337
338 private void writeChars(String str, int offset, int count)
339 throws IOException
340 {
341 do
342 {
343 converter.setOutput(work_bytes, 0);
344 int converted = converter.write(str, offset, count, work);
345 offset += converted;
346 count -= converted;
347 out.write(work_bytes, 0, converter.count);
348 }
349 while (count > 0 || converter.havePendingBytes());
350 }
351
352 /**
353 * This methods prints a boolean value to the stream. <code>true</code>
354 * values are printed as "true" and <code>false</code> values are printed
355 * as "false".
356 *
357 * @param bool The <code>boolean</code> value to print
358 */
359 public void print (boolean bool)
360 {
361 print(String.valueOf(bool), false);
362 }
363
364 /**
365 * This method prints an integer to the stream. The value printed is
366 * determined using the <code>String.valueOf()</code> method.
367 *
368 * @param inum The <code>int</code> value to be printed
369 */
370 public void print (int inum)
371 {
372 print(String.valueOf(inum), false);
373 }
374
375 /**
376 * This method prints a long to the stream. The value printed is
377 * determined using the <code>String.valueOf()</code> method.
378 *
379 * @param lnum The <code>long</code> value to be printed
380 */
381 public void print (long lnum)
382 {
383 print(String.valueOf(lnum), false);
384 }
385
386 /**
387 * This method prints a float to the stream. The value printed is
388 * determined using the <code>String.valueOf()</code> method.
389 *
390 * @param fnum The <code>float</code> value to be printed
391 */
392 public void print (float fnum)
393 {
394 print(String.valueOf(fnum), false);
395 }
396
397 /**
398 * This method prints a double to the stream. The value printed is
399 * determined using the <code>String.valueOf()</code> method.
400 *
401 * @param dnum The <code>double</code> value to be printed
402 */
403 public void print (double dnum)
404 {
405 print(String.valueOf(dnum), false);
406 }
407
408 /**
409 * This method prints an <code>Object</code> to the stream. The actual
410 * value printed is determined by calling the <code>String.valueOf()</code>
411 * method.
412 *
413 * @param obj The <code>Object</code> to print.
414 */
415 public void print (Object obj)
416 {
417 print(obj == null ? "null" : obj.toString(), false);
418 }
419
420 /**
421 * This method prints a <code>String</code> to the stream. The actual
422 * value printed depends on the system default encoding.
423 *
424 * @param str The <code>String</code> to print.
425 */
426 public void print (String str)
427 {
428 print(str == null ? "null" : str, false);
429 }
430
431 /**
432 * This method prints a char to the stream. The actual value printed is
433 * determined by the character encoding in use.
434 *
435 * @param ch The <code>char</code> value to be printed
436 */
437 public synchronized void print (char ch)
438 {
439 work[0] = ch;
440 print(work, 0, 1, false);
441 }
442
443 /**
444 * This method prints an array of characters to the stream. The actual
445 * value printed depends on the system default encoding.
446 *
447 * @param charArray The array of characters to print.
448 */
449 public void print (char[] charArray)
450 {
451 print(charArray, 0, charArray.length, false);
452 }
453
454 /**
455 * This method prints a line separator sequence to the stream. The value
456 * printed is determined by the system property <xmp>line.separator</xmp>
457 * and is not necessarily the Unix '\n' newline character.
458 */
459 public void println ()
460 {
461 print(line_separator, 0, line_separator.length, false);
462 }
463
464 /**
465 * This methods prints a boolean value to the stream. <code>true</code>
466 * values are printed as "true" and <code>false</code> values are printed
467 * as "false".
468 * <p>
469 * This method prints a line termination sequence after printing the value.
470 *
471 * @param bool The <code>boolean</code> value to print
472 */
473 public void println (boolean bool)
474 {
475 print(String.valueOf(bool), true);
476 }
477
478 /**
479 * This method prints an integer to the stream. The value printed is
480 * determined using the <code>String.valueOf()</code> method.
481 * <p>
482 * This method prints a line termination sequence after printing the value.
483 *
484 * @param inum The <code>int</code> value to be printed
485 */
486 public void println (int inum)
487 {
488 print(String.valueOf(inum), true);
489 }
490
491 /**
492 * This method prints a long to the stream. The value printed is
493 * determined using the <code>String.valueOf()</code> method.
494 * <p>
495 * This method prints a line termination sequence after printing the value.
496 *
497 * @param lnum The <code>long</code> value to be printed
498 */
499 public void println (long lnum)
500 {
501 print(String.valueOf(lnum), true);
502 }
503
504 /**
505 * This method prints a float to the stream. The value printed is
506 * determined using the <code>String.valueOf()</code> method.
507 * <p>
508 * This method prints a line termination sequence after printing the value.
509 *
510 * @param fnum The <code>float</code> value to be printed
511 */
512 public void println (float fnum)
513 {
514 print(String.valueOf(fnum), true);
515 }
516
517 /**
518 * This method prints a double to the stream. The value printed is
519 * determined using the <code>String.valueOf()</code> method.
520 * <p>
521 * This method prints a line termination sequence after printing the value.
522 *
523 * @param dnum The <code>double</code> value to be printed
524 */
525 public void println (double dnum)
526 {
527 print(String.valueOf(dnum), true);
528 }
529
530 /**
531 * This method prints an <code>Object</code> to the stream. The actual
532 * value printed is determined by calling the <code>String.valueOf()</code>
533 * method.
534 * <p>
535 * This method prints a line termination sequence after printing the value.
536 *
537 * @param obj The <code>Object</code> to print.
538 */
539 public void println (Object obj)
540 {
541 print(obj == null ? "null" : obj.toString(), true);
542 }
543
544 /**
545 * This method prints a <code>String</code> to the stream. The actual
546 * value printed depends on the system default encoding.
547 * <p>
548 * This method prints a line termination sequence after printing the value.
549 *
550 * @param str The <code>String</code> to print.
551 */
552 public void println (String str)
553 {
554 print (str == null ? "null" : str, true);
555 }
556
557 /**
558 * This method prints a char to the stream. The actual value printed is
559 * determined by the character encoding in use.
560 * <p>
561 * This method prints a line termination sequence after printing the value.
562 *
563 * @param ch The <code>char</code> value to be printed
564 */
565 public synchronized void println (char ch)
566 {
567 work[0] = ch;
568 print(work, 0, 1, true);
569 }
570
571 /**
572 * This method prints an array of characters to the stream. The actual
573 * value printed depends on the system default encoding.
574 * <p>
575 * This method prints a line termination sequence after printing the value.
576 *
577 * @param charArray The array of characters to print.
578 */
579 public void println (char[] charArray)
580 {
581 print(charArray, 0, charArray.length, true);
582 }
583
584 /**
585 * This method writes a byte of data to the stream. If auto-flush is
586 * enabled, printing a newline character will cause the stream to be
587 * flushed after the character is written.
588 *
589 * @param oneByte The byte to be written
590 */
591 public void write (int oneByte)
592 {
593 try
594 {
595 out.write (oneByte & 0xff);
596
597 if (auto_flush && (oneByte == '\n'))
598 flush ();
599 }
600 catch (InterruptedIOException iioe)
601 {
602 Thread.currentThread ().interrupt ();
603 }
604 catch (IOException e)
605 {
606 setError ();
607 }
608 }
609
610 /**
611 * This method writes <code>len</code> bytes from the specified array
612 * starting at index <code>offset</code> into the array.
613 *
614 * @param buffer The array of bytes to write
615 * @param offset The index into the array to start writing from
616 * @param len The number of bytes to write
617 */
618 public void write (byte[] buffer, int offset, int len)
619 {
620 try
621 {
622 out.write (buffer, offset, len);
623
624 if (auto_flush)
625 flush ();
626 }
627 catch (InterruptedIOException iioe)
628 {
629 Thread.currentThread ().interrupt ();
630 }
631 catch (IOException e)
632 {
633 setError ();
634 }
635 }
636
637 /** @since 1.5 */
638 public PrintStream append(char c)
639 {
640 print(c);
641 return this;
642 }
643
644 /** @since 1.5 */
645 public PrintStream append(CharSequence cs)
646 {
647 print(cs == null ? "null" : cs.toString());
648 return this;
649 }
650
651 /** @since 1.5 */
652 public PrintStream append(CharSequence cs, int start, int end)
653 {
654 print(cs == null ? "null" : cs.subSequence(start, end).toString());
655 return this;
656 }
657
658 /** @since 1.5 */
659 public PrintStream printf(String format, Object... args)
660 {
661 return format(format, args);
662 }
663
664 /** @since 1.5 */
665 public PrintStream printf(Locale locale, String format, Object... args)
666 {
667 return format(locale, format, args);
668 }
669
670 /** @since 1.5 */
671 public PrintStream format(String format, Object... args)
672 {
673 return format(Locale.getDefault(), format, args);
674 }
675
676 /** @since 1.5 */
677 public PrintStream format(Locale locale, String format, Object... args)
678 {
679 Formatter f = new Formatter(this, locale);
680 f.format(format, args);
681 return this;
682 }
683 } // class PrintStream
684