1 /*
2 * Copyright (c) 1996, 2013, 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 java.io;
27
28 import java.util.Formatter;
29 import java.util.Locale;
30 import java.nio.charset.Charset;
31 import java.nio.charset.IllegalCharsetNameException;
32 import java.nio.charset.UnsupportedCharsetException;
33
34 /**
35 * A {@code PrintStream} adds functionality to another output stream,
36 * namely the ability to print representations of various data values
37 * conveniently. Two other features are provided as well. Unlike other output
38 * streams, a {@code PrintStream} never throws an
39 * {@code IOException}; instead, exceptional situations merely set an
40 * internal flag that can be tested via the {@code checkError} method.
41 * Optionally, a {@code PrintStream} can be created so as to flush
42 * automatically; this means that the {@code flush} method is
43 * automatically invoked after a byte array is written, one of the
44 * {@code println} methods is invoked, or a newline character or byte
45 * ({@code '\n'}) is written.
46 *
47 * <p> All characters printed by a {@code PrintStream} are converted into
48 * bytes using the platform's default character encoding.
49 * The {@link PrintWriter} class should be used in situations that require
50 * writing characters rather than bytes.
51 *
52 * @author Frank Yellin
53 * @author Mark Reinhold
54 * @since 1.0
55 */
56
57 public class PrintStream extends FilterOutputStream
58 implements Appendable, Closeable
59 {
60
61 private final boolean autoFlush;
62 private boolean trouble = false;
63 private Formatter formatter;
64
65 /**
66 * Track both the text- and character-output streams, so that their buffers
67 * can be flushed without flushing the entire stream.
68 */
69 private BufferedWriter textOut;
70 private OutputStreamWriter charOut;
71
72 /**
73 * requireNonNull is explicitly declared here so as not to create an extra
74 * dependency on java.util.Objects.requireNonNull. PrintStream is loaded
75 * early during system initialization.
76 */
77 private static <T> T requireNonNull(T obj, String message) {
78 if (obj == null)
79 throw new NullPointerException(message);
80 return obj;
81 }
82
83 /**
84 * Returns a charset object for the given charset name.
85 * @throws NullPointerException is csn is null
86 * @throws UnsupportedEncodingException if the charset is not supported
87 */
88 private static Charset toCharset(String csn)
89 throws UnsupportedEncodingException
90 {
91 requireNonNull(csn, "charsetName");
92 try {
93 return Charset.forName(csn);
94 } catch (IllegalCharsetNameException|UnsupportedCharsetException unused) {
95 // UnsupportedEncodingException should be thrown
96 throw new UnsupportedEncodingException(csn);
97 }
98 }
99
100 /* Private constructors */
101 private PrintStream(boolean autoFlush, OutputStream out) {
102 super(out);
103 this.autoFlush = autoFlush;
104 this.charOut = new OutputStreamWriter(this);
105 this.textOut = new BufferedWriter(charOut);
106 }
107
108 private PrintStream(boolean autoFlush, OutputStream out, Charset charset) {
109 super(out);
110 this.autoFlush = autoFlush;
111 this.charOut = new OutputStreamWriter(this, charset);
112 this.textOut = new BufferedWriter(charOut);
113 }
114
115 /* Variant of the private constructor so that the given charset name
116 * can be verified before evaluating the OutputStream argument. Used
117 * by constructors creating a FileOutputStream that also take a
118 * charset name.
119 */
120 private PrintStream(boolean autoFlush, Charset charset, OutputStream out)
121 throws UnsupportedEncodingException
122 {
123 this(autoFlush, out, charset);
124 }
125
126 /**
127 * Creates a new print stream. This stream will not flush automatically.
128 *
129 * @param out The output stream to which values and objects will be
130 * printed
131 *
132 * @see java.io.PrintWriter#PrintWriter(java.io.OutputStream)
133 */
134 public PrintStream(OutputStream out) {
135 this(out, false);
136 }
137
138 /**
139 * Creates a new print stream.
140 *
141 * @param out The output stream to which values and objects will be
142 * printed
143 * @param autoFlush A boolean; if true, the output buffer will be flushed
144 * whenever a byte array is written, one of the
145 * {@code println} methods is invoked, or a newline
146 * character or byte ({@code '\n'}) is written
147 *
148 * @see java.io.PrintWriter#PrintWriter(java.io.OutputStream, boolean)
149 */
150 public PrintStream(OutputStream out, boolean autoFlush) {
151 this(autoFlush, requireNonNull(out, "Null output stream"));
152 }
153
154 /**
155 * Creates a new print stream.
156 *
157 * @param out The output stream to which values and objects will be
158 * printed
159 * @param autoFlush A boolean; if true, the output buffer will be flushed
160 * whenever a byte array is written, one of the
161 * {@code println} methods is invoked, or a newline
162 * character or byte ({@code '\n'}) is written
163 * @param encoding The name of a supported
164 * <a href="../lang/package-summary.html#charenc">
165 * character encoding</a>
166 *
167 * @throws UnsupportedEncodingException
168 * If the named encoding is not supported
169 *
170 * @since 1.4
171 */
172 public PrintStream(OutputStream out, boolean autoFlush, String encoding)
173 throws UnsupportedEncodingException
174 {
175 this(autoFlush,
176 requireNonNull(out, "Null output stream"),
177 toCharset(encoding));
178 }
179
180 /**
181 * Creates a new print stream, without automatic line flushing, with the
182 * specified file name. This convenience constructor creates
183 * the necessary intermediate {@link java.io.OutputStreamWriter
184 * OutputStreamWriter}, which will encode characters using the
185 * {@linkplain java.nio.charset.Charset#defaultCharset() default charset}
186 * for this instance of the Java virtual machine.
187 *
188 * @param fileName
189 * The name of the file to use as the destination of this print
190 * stream. If the file exists, then it will be truncated to
191 * zero size; otherwise, a new file will be created. The output
192 * will be written to the file and is buffered.
193 *
194 * @throws FileNotFoundException
195 * If the given file object does not denote an existing, writable
196 * regular file and a new regular file of that name cannot be
197 * created, or if some other error occurs while opening or
198 * creating the file
199 *
200 * @throws SecurityException
201 * If a security manager is present and {@link
202 * SecurityManager#checkWrite checkWrite(fileName)} denies write
203 * access to the file
204 *
205 * @since 1.5
206 */
207 public PrintStream(String fileName) throws FileNotFoundException {
208 this(false, new FileOutputStream(fileName));
209 }
210
211 /**
212 * Creates a new print stream, without automatic line flushing, with the
213 * specified file name and charset. This convenience constructor creates
214 * the necessary intermediate {@link java.io.OutputStreamWriter
215 * OutputStreamWriter}, which will encode characters using the provided
216 * charset.
217 *
218 * @param fileName
219 * The name of the file to use as the destination of this print
220 * stream. If the file exists, then it will be truncated to
221 * zero size; otherwise, a new file will be created. The output
222 * will be written to the file and is buffered.
223 *
224 * @param csn
225 * The name of a supported {@linkplain java.nio.charset.Charset
226 * charset}
227 *
228 * @throws FileNotFoundException
229 * If the given file object does not denote an existing, writable
230 * regular file and a new regular file of that name cannot be
231 * created, or if some other error occurs while opening or
232 * creating the file
233 *
234 * @throws SecurityException
235 * If a security manager is present and {@link
236 * SecurityManager#checkWrite checkWrite(fileName)} denies write
237 * access to the file
238 *
239 * @throws UnsupportedEncodingException
240 * If the named charset is not supported
241 *
242 * @since 1.5
243 */
244 public PrintStream(String fileName, String csn)
245 throws FileNotFoundException, UnsupportedEncodingException
246 {
247 // ensure charset is checked before the file is opened
248 this(false, toCharset(csn), new FileOutputStream(fileName));
249 }
250
251 /**
252 * Creates a new print stream, without automatic line flushing, with the
253 * specified file. This convenience constructor creates the necessary
254 * intermediate {@link java.io.OutputStreamWriter OutputStreamWriter},
255 * which will encode characters using the {@linkplain
256 * java.nio.charset.Charset#defaultCharset() default charset} for this
257 * instance of the Java virtual machine.
258 *
259 * @param file
260 * The file to use as the destination of this print stream. If the
261 * file exists, then it will be truncated to zero size; otherwise,
262 * a new file will be created. The output will be written to the
263 * file and is buffered.
264 *
265 * @throws FileNotFoundException
266 * If the given file object does not denote an existing, writable
267 * regular file and a new regular file of that name cannot be
268 * created, or if some other error occurs while opening or
269 * creating the file
270 *
271 * @throws SecurityException
272 * If a security manager is present and {@link
273 * SecurityManager#checkWrite checkWrite(file.getPath())}
274 * denies write access to the file
275 *
276 * @since 1.5
277 */
278 public PrintStream(File file) throws FileNotFoundException {
279 this(false, new FileOutputStream(file));
280 }
281
282 /**
283 * Creates a new print stream, without automatic line flushing, with the
284 * specified file and charset. This convenience constructor creates
285 * the necessary intermediate {@link java.io.OutputStreamWriter
286 * OutputStreamWriter}, which will encode characters using the provided
287 * charset.
288 *
289 * @param file
290 * The file to use as the destination of this print stream. If the
291 * file exists, then it will be truncated to zero size; otherwise,
292 * a new file will be created. The output will be written to the
293 * file and is buffered.
294 *
295 * @param csn
296 * The name of a supported {@linkplain java.nio.charset.Charset
297 * charset}
298 *
299 * @throws FileNotFoundException
300 * If the given file object does not denote an existing, writable
301 * regular file and a new regular file of that name cannot be
302 * created, or if some other error occurs while opening or
303 * creating the file
304 *
305 * @throws SecurityException
306 * If a security manager is present and {@link
307 * SecurityManager#checkWrite checkWrite(file.getPath())}
308 * denies write access to the file
309 *
310 * @throws UnsupportedEncodingException
311 * If the named charset is not supported
312 *
313 * @since 1.5
314 */
315 public PrintStream(File file, String csn)
316 throws FileNotFoundException, UnsupportedEncodingException
317 {
318 // ensure charset is checked before the file is opened
319 this(false, toCharset(csn), new FileOutputStream(file));
320 }
321
322 /** Check to make sure that the stream has not been closed */
323 private void ensureOpen() throws IOException {
324 if (out == null)
325 throw new IOException("Stream closed");
326 }
327
328 /**
329 * Flushes the stream. This is done by writing any buffered output bytes to
330 * the underlying output stream and then flushing that stream.
331 *
332 * @see java.io.OutputStream#flush()
333 */
334 public void flush() {
335 synchronized (this) {
336 try {
337 ensureOpen();
338 out.flush();
339 }
340 catch (IOException x) {
341 trouble = true;
342 }
343 }
344 }
345
346 private boolean closing = false; /* To avoid recursive closing */
347
348 /**
349 * Closes the stream. This is done by flushing the stream and then closing
350 * the underlying output stream.
351 *
352 * @see java.io.OutputStream#close()
353 */
354 public void close() {
355 synchronized (this) {
356 if (! closing) {
357 closing = true;
358 try {
359 textOut.close();
360 out.close();
361 }
362 catch (IOException x) {
363 trouble = true;
364 }
365 textOut = null;
366 charOut = null;
367 out = null;
368 }
369 }
370 }
371
372 /**
373 * Flushes the stream and checks its error state. The internal error state
374 * is set to {@code true} when the underlying output stream throws an
375 * {@code IOException} other than {@code InterruptedIOException},
376 * and when the {@code setError} method is invoked. If an operation
377 * on the underlying output stream throws an
378 * {@code InterruptedIOException}, then the {@code PrintStream}
379 * converts the exception back into an interrupt by doing:
380 * <pre>{@code
381 * Thread.currentThread().interrupt();
382 * }</pre>
383 * or the equivalent.
384 *
385 * @return {@code true} if and only if this stream has encountered an
386 * {@code IOException} other than
387 * {@code InterruptedIOException}, or the
388 * {@code setError} method has been invoked
389 */
390 public boolean checkError() {
391 if (out != null)
392 flush();
393 if (out instanceof java.io.PrintStream) {
394 PrintStream ps = (PrintStream) out;
395 return ps.checkError();
396 }
397 return trouble;
398 }
399
400 /**
401 * Sets the error state of the stream to {@code true}.
402 *
403 * <p> This method will cause subsequent invocations of {@link
404 * #checkError()} to return {@code true} until
405 * {@link #clearError()} is invoked.
406 *
407 * @since 1.1
408 */
409 protected void setError() {
410 trouble = true;
411 }
412
413 /**
414 * Clears the internal error state of this stream.
415 *
416 * <p> This method will cause subsequent invocations of {@link
417 * #checkError()} to return {@code false} until another write
418 * operation fails and invokes {@link #setError()}.
419 *
420 * @since 1.6
421 */
422 protected void clearError() {
423 trouble = false;
424 }
425
426 /*
427 * Exception-catching, synchronized output operations,
428 * which also implement the write() methods of OutputStream
429 */
430
431 /**
432 * Writes the specified byte to this stream. If the byte is a newline and
433 * automatic flushing is enabled then the {@code flush} method will be
434 * invoked.
435 *
436 * <p> Note that the byte is written as given; to write a character that
437 * will be translated according to the platform's default character
438 * encoding, use the {@code print(char)} or {@code println(char)}
439 * methods.
440 *
441 * @param b The byte to be written
442 * @see #print(char)
443 * @see #println(char)
444 */
445 public void write(int b) {
446 try {
447 synchronized (this) {
448 ensureOpen();
449 out.write(b);
450 if ((b == '\n') && autoFlush)
451 out.flush();
452 }
453 }
454 catch (InterruptedIOException x) {
455 Thread.currentThread().interrupt();
456 }
457 catch (IOException x) {
458 trouble = true;
459 }
460 }
461
462 /**
463 * Writes {@code len} bytes from the specified byte array starting at
464 * offset {@code off} to this stream. If automatic flushing is
465 * enabled then the {@code flush} method will be invoked.
466 *
467 * <p> Note that the bytes will be written as given; to write characters
468 * that will be translated according to the platform's default character
469 * encoding, use the {@code print(char)} or {@code println(char)}
470 * methods.
471 *
472 * @param buf A byte array
473 * @param off Offset from which to start taking bytes
474 * @param len Number of bytes to write
475 */
476 public void write(byte buf[], int off, int len) {
477 try {
478 synchronized (this) {
479 ensureOpen();
480 out.write(buf, off, len);
481 if (autoFlush)
482 out.flush();
483 }
484 }
485 catch (InterruptedIOException x) {
486 Thread.currentThread().interrupt();
487 }
488 catch (IOException x) {
489 trouble = true;
490 }
491 }
492
493 /*
494 * The following private methods on the text- and character-output streams
495 * always flush the stream buffers, so that writes to the underlying byte
496 * stream occur as promptly as with the original PrintStream.
497 */
498
499 private void write(char buf[]) {
500 try {
501 synchronized (this) {
502 ensureOpen();
503 textOut.write(buf);
504 textOut.flushBuffer();
505 charOut.flushBuffer();
506 if (autoFlush) {
507 for (int i = 0; i < buf.length; i++)
508 if (buf[i] == '\n')
509 out.flush();
510 }
511 }
512 }
513 catch (InterruptedIOException x) {
514 Thread.currentThread().interrupt();
515 }
516 catch (IOException x) {
517 trouble = true;
518 }
519 }
520
521 private void write(String s) {
522 try {
523 synchronized (this) {
524 ensureOpen();
525 textOut.write(s);
526 textOut.flushBuffer();
527 charOut.flushBuffer();
528 if (autoFlush && (s.indexOf('\n') >= 0))
529 out.flush();
530 }
531 }
532 catch (InterruptedIOException x) {
533 Thread.currentThread().interrupt();
534 }
535 catch (IOException x) {
536 trouble = true;
537 }
538 }
539
540 private void newLine() {
541 try {
542 synchronized (this) {
543 ensureOpen();
544 textOut.newLine();
545 textOut.flushBuffer();
546 charOut.flushBuffer();
547 if (autoFlush)
548 out.flush();
549 }
550 }
551 catch (InterruptedIOException x) {
552 Thread.currentThread().interrupt();
553 }
554 catch (IOException x) {
555 trouble = true;
556 }
557 }
558
559 /* Methods that do not terminate lines */
560
561 /**
562 * Prints a boolean value. The string produced by {@link
563 * java.lang.String#valueOf(boolean)} is translated into bytes
564 * according to the platform's default character encoding, and these bytes
565 * are written in exactly the manner of the
566 * {@link #write(int)} method.
567 *
568 * @param b The {@code boolean} to be printed
569 */
570 public void print(boolean b) {
571 write(String.valueOf(b));
572 }
573
574 /**
575 * Prints a character. The character is translated into one or more bytes
576 * according to the platform's default character encoding, and these bytes
577 * are written in exactly the manner of the
578 * {@link #write(int)} method.
579 *
580 * @param c The {@code char} to be printed
581 */
582 public void print(char c) {
583 write(String.valueOf(c));
584 }
585
586 /**
587 * Prints an integer. The string produced by {@link
588 * java.lang.String#valueOf(int)} is translated into bytes
589 * according to the platform's default character encoding, and these bytes
590 * are written in exactly the manner of the
591 * {@link #write(int)} method.
592 *
593 * @param i The {@code int} to be printed
594 * @see java.lang.Integer#toString(int)
595 */
596 public void print(int i) {
597 write(String.valueOf(i));
598 }
599
600 /**
601 * Prints a long integer. The string produced by {@link
602 * java.lang.String#valueOf(long)} is translated into bytes
603 * according to the platform's default character encoding, and these bytes
604 * are written in exactly the manner of the
605 * {@link #write(int)} method.
606 *
607 * @param l The {@code long} to be printed
608 * @see java.lang.Long#toString(long)
609 */
610 public void print(long l) {
611 write(String.valueOf(l));
612 }
613
614 /**
615 * Prints a floating-point number. The string produced by {@link
616 * java.lang.String#valueOf(float)} is translated into bytes
617 * according to the platform's default character encoding, and these bytes
618 * are written in exactly the manner of the
619 * {@link #write(int)} method.
620 *
621 * @param f The {@code float} to be printed
622 * @see java.lang.Float#toString(float)
623 */
624 public void print(float f) {
625 write(String.valueOf(f));
626 }
627
628 /**
629 * Prints a double-precision floating-point number. The string produced by
630 * {@link java.lang.String#valueOf(double)} is translated into
631 * bytes according to the platform's default character encoding, and these
632 * bytes are written in exactly the manner of the {@link
633 * #write(int)} method.
634 *
635 * @param d The {@code double} to be printed
636 * @see java.lang.Double#toString(double)
637 */
638 public void print(double d) {
639 write(String.valueOf(d));
640 }
641
642 /**
643 * Prints an array of characters. The characters are converted into bytes
644 * according to the platform's default character encoding, and these bytes
645 * are written in exactly the manner of the
646 * {@link #write(int)} method.
647 *
648 * @param s The array of chars to be printed
649 *
650 * @throws NullPointerException If {@code s} is {@code null}
651 */
652 public void print(char s[]) {
653 write(s);
654 }
655
656 /**
657 * Prints a string. If the argument is {@code null} then the string
658 * {@code "null"} is printed. Otherwise, the string's characters are
659 * converted into bytes according to the platform's default character
660 * encoding, and these bytes are written in exactly the manner of the
661 * {@link #write(int)} method.
662 *
663 * @param s The {@code String} to be printed
664 */
665 public void print(String s) {
666 write(String.valueOf(s));
667 }
668
669 /**
670 * Prints an object. The string produced by the {@link
671 * java.lang.String#valueOf(Object)} method is translated into bytes
672 * according to the platform's default character encoding, and these bytes
673 * are written in exactly the manner of the
674 * {@link #write(int)} method.
675 *
676 * @param obj The {@code Object} to be printed
677 * @see java.lang.Object#toString()
678 */
679 public void print(Object obj) {
680 write(String.valueOf(obj));
681 }
682
683
684 /* Methods that do terminate lines */
685
686 /**
687 * Terminates the current line by writing the line separator string. The
688 * line separator string is defined by the system property
689 * {@code line.separator}, and is not necessarily a single newline
690 * character ({@code '\n'}).
691 */
692 public void println() {
693 newLine();
694 }
695
696 /**
697 * Prints a boolean and then terminate the line. This method behaves as
698 * though it invokes {@link #print(boolean)} and then
699 * {@link #println()}.
700 *
701 * @param x The {@code boolean} to be printed
702 */
703 public void println(boolean x) {
704 synchronized (this) {
705 print(x);
706 newLine();
707 }
708 }
709
710 /**
711 * Prints a character and then terminate the line. This method behaves as
712 * though it invokes {@link #print(char)} and then
713 * {@link #println()}.
714 *
715 * @param x The {@code char} to be printed.
716 */
717 public void println(char x) {
718 synchronized (this) {
719 print(x);
720 newLine();
721 }
722 }
723
724 /**
725 * Prints an integer and then terminate the line. This method behaves as
726 * though it invokes {@link #print(int)} and then
727 * {@link #println()}.
728 *
729 * @param x The {@code int} to be printed.
730 */
731 public void println(int x) {
732 synchronized (this) {
733 print(x);
734 newLine();
735 }
736 }
737
738 /**
739 * Prints a long and then terminate the line. This method behaves as
740 * though it invokes {@link #print(long)} and then
741 * {@link #println()}.
742 *
743 * @param x a The {@code long} to be printed.
744 */
745 public void println(long x) {
746 synchronized (this) {
747 print(x);
748 newLine();
749 }
750 }
751
752 /**
753 * Prints a float and then terminate the line. This method behaves as
754 * though it invokes {@link #print(float)} and then
755 * {@link #println()}.
756 *
757 * @param x The {@code float} to be printed.
758 */
759 public void println(float x) {
760 synchronized (this) {
761 print(x);
762 newLine();
763 }
764 }
765
766 /**
767 * Prints a double and then terminate the line. This method behaves as
768 * though it invokes {@link #print(double)} and then
769 * {@link #println()}.
770 *
771 * @param x The {@code double} to be printed.
772 */
773 public void println(double x) {
774 synchronized (this) {
775 print(x);
776 newLine();
777 }
778 }
779
780 /**
781 * Prints an array of characters and then terminate the line. This method
782 * behaves as though it invokes {@link #print(char[])} and
783 * then {@link #println()}.
784 *
785 * @param x an array of chars to print.
786 */
787 public void println(char x[]) {
788 synchronized (this) {
789 print(x);
790 newLine();
791 }
792 }
793
794 /**
795 * Prints a String and then terminate the line. This method behaves as
796 * though it invokes {@link #print(String)} and then
797 * {@link #println()}.
798 *
799 * @param x The {@code String} to be printed.
800 */
801 public void println(String x) {
802 synchronized (this) {
803 print(x);
804 newLine();
805 }
806 }
807
808 /**
809 * Prints an Object and then terminate the line. This method calls
810 * at first String.valueOf(x) to get the printed object's string value,
811 * then behaves as
812 * though it invokes {@link #print(String)} and then
813 * {@link #println()}.
814 *
815 * @param x The {@code Object} to be printed.
816 */
817 public void println(Object x) {
818 String s = String.valueOf(x);
819 synchronized (this) {
820 print(s);
821 newLine();
822 }
823 }
824
825
826 /**
827 * A convenience method to write a formatted string to this output stream
828 * using the specified format string and arguments.
829 *
830 * <p> An invocation of this method of the form
831 * {@code out.printf(format, args)} behaves
832 * in exactly the same way as the invocation
833 *
834 * <pre>{@code
835 * out.format(format, args)
836 * }</pre>
837 *
838 * @param format
839 * A format string as described in <a
840 * href="../util/Formatter.html#syntax">Format string syntax</a>
841 *
842 * @param args
843 * Arguments referenced by the format specifiers in the format
844 * string. If there are more arguments than format specifiers, the
845 * extra arguments are ignored. The number of arguments is
846 * variable and may be zero. The maximum number of arguments is
847 * limited by the maximum dimension of a Java array as defined by
848 * <cite>The Java™ Virtual Machine Specification</cite>.
849 * The behaviour on a
850 * {@code null} argument depends on the <a
851 * href="../util/Formatter.html#syntax">conversion</a>.
852 *
853 * @throws java.util.IllegalFormatException
854 * If a format string contains an illegal syntax, a format
855 * specifier that is incompatible with the given arguments,
856 * insufficient arguments given the format string, or other
857 * illegal conditions. For specification of all possible
858 * formatting errors, see the <a
859 * href="../util/Formatter.html#detail">Details</a> section of the
860 * formatter class specification.
861 *
862 * @throws NullPointerException
863 * If the {@code format} is {@code null}
864 *
865 * @return This output stream
866 *
867 * @since 1.5
868 */
869 public PrintStream printf(String format, Object ... args) {
870 return format(format, args);
871 }
872
873 /**
874 * A convenience method to write a formatted string to this output stream
875 * using the specified format string and arguments.
876 *
877 * <p> An invocation of this method of the form
878 * {@code out.printf(l, format, args)} behaves
879 * in exactly the same way as the invocation
880 *
881 * <pre>{@code
882 * out.format(l, format, args)
883 * }</pre>
884 *
885 * @param l
886 * The {@linkplain java.util.Locale locale} to apply during
887 * formatting. If {@code l} is {@code null} then no localization
888 * is applied.
889 *
890 * @param format
891 * A format string as described in <a
892 * href="../util/Formatter.html#syntax">Format string syntax</a>
893 *
894 * @param args
895 * Arguments referenced by the format specifiers in the format
896 * string. If there are more arguments than format specifiers, the
897 * extra arguments are ignored. The number of arguments is
898 * variable and may be zero. The maximum number of arguments is
899 * limited by the maximum dimension of a Java array as defined by
900 * <cite>The Java™ Virtual Machine Specification</cite>.
901 * The behaviour on a
902 * {@code null} argument depends on the <a
903 * href="../util/Formatter.html#syntax">conversion</a>.
904 *
905 * @throws java.util.IllegalFormatException
906 * If a format string contains an illegal syntax, a format
907 * specifier that is incompatible with the given arguments,
908 * insufficient arguments given the format string, or other
909 * illegal conditions. For specification of all possible
910 * formatting errors, see the <a
911 * href="../util/Formatter.html#detail">Details</a> section of the
912 * formatter class specification.
913 *
914 * @throws NullPointerException
915 * If the {@code format} is {@code null}
916 *
917 * @return This output stream
918 *
919 * @since 1.5
920 */
921 public PrintStream printf(Locale l, String format, Object ... args) {
922 return format(l, format, args);
923 }
924
925 /**
926 * Writes a formatted string to this output stream using the specified
927 * format string and arguments.
928 *
929 * <p> The locale always used is the one returned by {@link
930 * java.util.Locale#getDefault(Locale.Category)} with
931 * {@link java.util.Locale.Category#FORMAT FORMAT} category specified,
932 * regardless of any previous invocations of other formatting methods on
933 * this object.
934 *
935 * @param format
936 * A format string as described in <a
937 * href="../util/Formatter.html#syntax">Format string syntax</a>
938 *
939 * @param args
940 * Arguments referenced by the format specifiers in the format
941 * string. If there are more arguments than format specifiers, the
942 * extra arguments are ignored. The number of arguments is
943 * variable and may be zero. The maximum number of arguments is
944 * limited by the maximum dimension of a Java array as defined by
945 * <cite>The Java™ Virtual Machine Specification</cite>.
946 * The behaviour on a
947 * {@code null} argument depends on the <a
948 * href="../util/Formatter.html#syntax">conversion</a>.
949 *
950 * @throws java.util.IllegalFormatException
951 * If a format string contains an illegal syntax, a format
952 * specifier that is incompatible with the given arguments,
953 * insufficient arguments given the format string, or other
954 * illegal conditions. For specification of all possible
955 * formatting errors, see the <a
956 * href="../util/Formatter.html#detail">Details</a> section of the
957 * formatter class specification.
958 *
959 * @throws NullPointerException
960 * If the {@code format} is {@code null}
961 *
962 * @return This output stream
963 *
964 * @since 1.5
965 */
966 public PrintStream format(String format, Object ... args) {
967 try {
968 synchronized (this) {
969 ensureOpen();
970 if ((formatter == null)
971 || (formatter.locale() !=
972 Locale.getDefault(Locale.Category.FORMAT)))
973 formatter = new Formatter((Appendable) this);
974 formatter.format(Locale.getDefault(Locale.Category.FORMAT),
975 format, args);
976 }
977 } catch (InterruptedIOException x) {
978 Thread.currentThread().interrupt();
979 } catch (IOException x) {
980 trouble = true;
981 }
982 return this;
983 }
984
985 /**
986 * Writes a formatted string to this output stream using the specified
987 * format string and arguments.
988 *
989 * @param l
990 * The {@linkplain java.util.Locale locale} to apply during
991 * formatting. If {@code l} is {@code null} then no localization
992 * is applied.
993 *
994 * @param format
995 * A format string as described in <a
996 * href="../util/Formatter.html#syntax">Format string syntax</a>
997 *
998 * @param args
999 * Arguments referenced by the format specifiers in the format
1000 * string. If there are more arguments than format specifiers, the
1001 * extra arguments are ignored. The number of arguments is
1002 * variable and may be zero. The maximum number of arguments is
1003 * limited by the maximum dimension of a Java array as defined by
1004 * <cite>The Java™ Virtual Machine Specification</cite>.
1005 * The behaviour on a
1006 * {@code null} argument depends on the <a
1007 * href="../util/Formatter.html#syntax">conversion</a>.
1008 *
1009 * @throws java.util.IllegalFormatException
1010 * If a format string contains an illegal syntax, a format
1011 * specifier that is incompatible with the given arguments,
1012 * insufficient arguments given the format string, or other
1013 * illegal conditions. For specification of all possible
1014 * formatting errors, see the <a
1015 * href="../util/Formatter.html#detail">Details</a> section of the
1016 * formatter class specification.
1017 *
1018 * @throws NullPointerException
1019 * If the {@code format} is {@code null}
1020 *
1021 * @return This output stream
1022 *
1023 * @since 1.5
1024 */
1025 public PrintStream format(Locale l, String format, Object ... args) {
1026 try {
1027 synchronized (this) {
1028 ensureOpen();
1029 if ((formatter == null)
1030 || (formatter.locale() != l))
1031 formatter = new Formatter(this, l);
1032 formatter.format(l, format, args);
1033 }
1034 } catch (InterruptedIOException x) {
1035 Thread.currentThread().interrupt();
1036 } catch (IOException x) {
1037 trouble = true;
1038 }
1039 return this;
1040 }
1041
1042 /**
1043 * Appends the specified character sequence to this output stream.
1044 *
1045 * <p> An invocation of this method of the form {@code out.append(csq)}
1046 * behaves in exactly the same way as the invocation
1047 *
1048 * <pre>{@code
1049 * out.print(csq.toString())
1050 * }</pre>
1051 *
1052 * <p> Depending on the specification of {@code toString} for the
1053 * character sequence {@code csq}, the entire sequence may not be
1054 * appended. For instance, invoking then {@code toString} method of a
1055 * character buffer will return a subsequence whose content depends upon
1056 * the buffer's position and limit.
1057 *
1058 * @param csq
1059 * The character sequence to append. If {@code csq} is
1060 * {@code null}, then the four characters {@code "null"} are
1061 * appended to this output stream.
1062 *
1063 * @return This output stream
1064 *
1065 * @since 1.5
1066 */
1067 public PrintStream append(CharSequence csq) {
1068 print(String.valueOf(csq));
1069 return this;
1070 }
1071
1072 /**
1073 * Appends a subsequence of the specified character sequence to this output
1074 * stream.
1075 *
1076 * <p> An invocation of this method of the form
1077 * {@code out.append(csq, start, end)} when
1078 * {@code csq} is not {@code null}, behaves in
1079 * exactly the same way as the invocation
1080 *
1081 * <pre>{@code
1082 * out.print(csq.subSequence(start, end).toString())
1083 * }</pre>
1084 *
1085 * @param csq
1086 * The character sequence from which a subsequence will be
1087 * appended. If {@code csq} is {@code null}, then characters
1088 * will be appended as if {@code csq} contained the four
1089 * characters {@code "null"}.
1090 *
1091 * @param start
1092 * The index of the first character in the subsequence
1093 *
1094 * @param end
1095 * The index of the character following the last character in the
1096 * subsequence
1097 *
1098 * @return This output stream
1099 *
1100 * @throws IndexOutOfBoundsException
1101 * If {@code start} or {@code end} are negative, {@code start}
1102 * is greater than {@code end}, or {@code end} is greater than
1103 * {@code csq.length()}
1104 *
1105 * @since 1.5
1106 */
1107 public PrintStream append(CharSequence csq, int start, int end) {
1108 if (csq == null) csq = "null";
1109 return append(csq.subSequence(start, end));
1110 }
1111
1112 /**
1113 * Appends the specified character to this output stream.
1114 *
1115 * <p> An invocation of this method of the form {@code out.append(c)}
1116 * behaves in exactly the same way as the invocation
1117 *
1118 * <pre>{@code
1119 * out.print(c)
1120 * }</pre>
1121 *
1122 * @param c
1123 * The 16-bit character to append
1124 *
1125 * @return This output stream
1126 *
1127 * @since 1.5
1128 */
1129 public PrintStream append(char c) {
1130 print(c);
1131 return this;
1132 }
1133
1134 }