1 /* 2 * Copyright (c) 1996, 2017, 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 given encoding or charset, or platform's default character 49 * encoding if not specified. 50 * The {@link PrintWriter} class should be used in situations that require 51 * writing characters rather than bytes. 52 * 53 * <p> This class always replaces malformed and unmappable character sequences with 54 * the charset's default replacement string. 55 * The {@linkplain java.nio.charset.CharsetEncoder} class should be used when more 56 * control over the encoding process is required. 57 * 58 * @author Frank Yellin 59 * @author Mark Reinhold 60 * @since 1.0 61 */ 62 63 public class PrintStream extends FilterOutputStream 64 implements Appendable, Closeable 65 { 66 67 private final boolean autoFlush; 68 private boolean trouble = false; 69 private Formatter formatter; 70 71 /** 72 * Track both the text- and character-output streams, so that their buffers 73 * can be flushed without flushing the entire stream. 74 */ 75 private BufferedWriter textOut; 76 private OutputStreamWriter charOut; 77 78 /** 79 * requireNonNull is explicitly declared here so as not to create an extra 80 * dependency on java.util.Objects.requireNonNull. PrintStream is loaded 81 * early during system initialization. 82 */ 83 private static <T> T requireNonNull(T obj, String message) { 84 if (obj == null) 85 throw new NullPointerException(message); 86 return obj; 87 } 88 89 /** 90 * Returns a charset object for the given charset name. 91 * @throws NullPointerException is csn is null 92 * @throws UnsupportedEncodingException if the charset is not supported 93 */ 94 private static Charset toCharset(String csn) 95 throws UnsupportedEncodingException 96 { 97 requireNonNull(csn, "charsetName"); 98 try { 99 return Charset.forName(csn); 100 } catch (IllegalCharsetNameException|UnsupportedCharsetException unused) { 101 // UnsupportedEncodingException should be thrown 102 throw new UnsupportedEncodingException(csn); 103 } 104 } 105 106 /* Private constructors */ 107 private PrintStream(boolean autoFlush, OutputStream out) { 108 super(out); 109 this.autoFlush = autoFlush; 110 this.charOut = new OutputStreamWriter(this); 111 this.textOut = new BufferedWriter(charOut); 112 } 113 114 /* Variant of the private constructor so that the given charset name 115 * can be verified before evaluating the OutputStream argument. Used 116 * by constructors creating a FileOutputStream that also take a 117 * charset name. 118 */ 119 private PrintStream(boolean autoFlush, Charset charset, OutputStream out) { 120 this(out, autoFlush, charset); 121 } 122 123 /** 124 * Creates a new print stream. This stream will not flush automatically. 125 * 126 * @param out The output stream to which values and objects will be 127 * printed 128 * 129 * @see java.io.PrintWriter#PrintWriter(java.io.OutputStream) 130 */ 131 public PrintStream(OutputStream out) { 132 this(out, false); 133 } 134 135 /** 136 * Creates a new print stream. 137 * 138 * @param out The output stream to which values and objects will be 139 * printed 140 * @param autoFlush A boolean; if true, the output buffer will be flushed 141 * whenever a byte array is written, one of the 142 * {@code println} methods is invoked, or a newline 143 * character or byte ({@code '\n'}) is written 144 * 145 * @see java.io.PrintWriter#PrintWriter(java.io.OutputStream, boolean) 146 */ 147 public PrintStream(OutputStream out, boolean autoFlush) { 148 this(autoFlush, requireNonNull(out, "Null output stream")); 149 } 150 151 /** 152 * Creates a new print stream. 153 * 154 * @param out The output stream to which values and objects will be 155 * printed 156 * @param autoFlush A boolean; if true, the output buffer will be flushed 157 * whenever a byte array is written, one of the 158 * {@code println} methods is invoked, or a newline 159 * character or byte ({@code '\n'}) is written 160 * @param encoding The name of a supported 161 * <a href="../lang/package-summary.html#charenc"> 162 * character encoding</a> 163 * 164 * @throws UnsupportedEncodingException 165 * If the named encoding is not supported 166 * 167 * @since 1.4 168 */ 169 public PrintStream(OutputStream out, boolean autoFlush, String encoding) 170 throws UnsupportedEncodingException 171 { 172 this(requireNonNull(out, "Null output stream"), autoFlush, toCharset(encoding)); 173 } 174 175 /** 176 * Creates a new print stream, with the specified OutputStream, automatic line 177 * flushing and charset. This convenience constructor creates the necessary 178 * intermediate {@link java.io.OutputStreamWriter OutputStreamWriter}, 179 * which will encode characters using the provided charset. 180 * 181 * @param out The output stream to which values and objects will be 182 * printed 183 * @param autoFlush A boolean; if true, the output buffer will be flushed 184 * whenever a byte array is written, one of the 185 * {@code println} methods is invoked, or a newline 186 * character or byte ({@code '\n'}) is written 187 * @param charset A {@linkplain java.nio.charset.Charset charset} 188 * 189 * @since 10 190 */ 191 public PrintStream(OutputStream out, boolean autoFlush, Charset charset) { 192 super(out); 193 this.autoFlush = autoFlush; 194 this.charOut = new OutputStreamWriter(this, charset); 195 this.textOut = new BufferedWriter(charOut); 196 } 197 198 /** 199 * Creates a new print stream, without automatic line flushing, with the 200 * specified file name. This convenience constructor creates 201 * the necessary intermediate {@link java.io.OutputStreamWriter 202 * OutputStreamWriter}, which will encode characters using the 203 * {@linkplain java.nio.charset.Charset#defaultCharset() default charset} 204 * for this instance of the Java virtual machine. 205 * 206 * @param fileName 207 * The name of the file to use as the destination of this print 208 * stream. If the file exists, then it will be truncated to 209 * zero size; otherwise, a new file will be created. The output 210 * will be written to the file and is buffered. 211 * 212 * @throws FileNotFoundException 213 * If the given file object does not denote an existing, writable 214 * regular file and a new regular file of that name cannot be 215 * created, or if some other error occurs while opening or 216 * creating the file 217 * 218 * @throws SecurityException 219 * If a security manager is present and {@link 220 * SecurityManager#checkWrite checkWrite(fileName)} denies write 221 * access to the file 222 * 223 * @since 1.5 224 */ 225 public PrintStream(String fileName) throws FileNotFoundException { 226 this(false, new FileOutputStream(fileName)); 227 } 228 229 /** 230 * Creates a new print stream, without automatic line flushing, with the 231 * specified file name and charset. This convenience constructor creates 232 * the necessary intermediate {@link java.io.OutputStreamWriter 233 * OutputStreamWriter}, which will encode characters using the provided 234 * charset. 235 * 236 * @param fileName 237 * The name of the file to use as the destination of this print 238 * stream. If the file exists, then it will be truncated to 239 * zero size; otherwise, a new file will be created. The output 240 * will be written to the file and is buffered. 241 * 242 * @param csn 243 * The name of a supported {@linkplain java.nio.charset.Charset 244 * charset} 245 * 246 * @throws FileNotFoundException 247 * If the given file object does not denote an existing, writable 248 * regular file and a new regular file of that name cannot be 249 * created, or if some other error occurs while opening or 250 * creating the file 251 * 252 * @throws SecurityException 253 * If a security manager is present and {@link 254 * SecurityManager#checkWrite checkWrite(fileName)} denies write 255 * access to the file 256 * 257 * @throws UnsupportedEncodingException 258 * If the named charset is not supported 259 * 260 * @since 1.5 261 */ 262 public PrintStream(String fileName, String csn) 263 throws FileNotFoundException, UnsupportedEncodingException 264 { 265 // ensure charset is checked before the file is opened 266 this(false, toCharset(csn), new FileOutputStream(fileName)); 267 } 268 269 /** 270 * Creates a new print stream, without automatic line flushing, with the 271 * specified file name and charset. This convenience constructor creates 272 * the necessary intermediate {@link java.io.OutputStreamWriter 273 * OutputStreamWriter}, which will encode characters using the provided 274 * charset. 275 * 276 * @param fileName 277 * The name of the file to use as the destination of this print 278 * stream. If the file exists, then it will be truncated to 279 * zero size; otherwise, a new file will be created. The output 280 * will be written to the file and is buffered. 281 * 282 * @param charset 283 * A {@linkplain java.nio.charset.Charset charset} 284 * 285 * @throws IOException 286 * if an I/O error occurs while opening or creating the file 287 * 288 * @throws SecurityException 289 * If a security manager is present and {@link 290 * SecurityManager#checkWrite checkWrite(fileName)} denies write 291 * access to the file 292 * 293 * @since 10 294 */ 295 public PrintStream(String fileName, Charset charset) throws IOException { 296 this(false, requireNonNull(charset, "charset"), new FileOutputStream(fileName)); 297 } 298 299 /** 300 * Creates a new print stream, without automatic line flushing, with the 301 * specified file. This convenience constructor creates the necessary 302 * intermediate {@link java.io.OutputStreamWriter OutputStreamWriter}, 303 * which will encode characters using the {@linkplain 304 * java.nio.charset.Charset#defaultCharset() default charset} for this 305 * instance of the Java virtual machine. 306 * 307 * @param file 308 * The file to use as the destination of this print stream. If the 309 * file exists, then it will be truncated to zero size; otherwise, 310 * a new file will be created. The output will be written to the 311 * file and is buffered. 312 * 313 * @throws FileNotFoundException 314 * If the given file object does not denote an existing, writable 315 * regular file and a new regular file of that name cannot be 316 * created, or if some other error occurs while opening or 317 * creating the file 318 * 319 * @throws SecurityException 320 * If a security manager is present and {@link 321 * SecurityManager#checkWrite checkWrite(file.getPath())} 322 * denies write access to the file 323 * 324 * @since 1.5 325 */ 326 public PrintStream(File file) throws FileNotFoundException { 327 this(false, new FileOutputStream(file)); 328 } 329 330 /** 331 * Creates a new print stream, without automatic line flushing, with the 332 * specified file and charset. This convenience constructor creates 333 * the necessary intermediate {@link java.io.OutputStreamWriter 334 * OutputStreamWriter}, which will encode characters using the provided 335 * charset. 336 * 337 * @param file 338 * The file to use as the destination of this print stream. If the 339 * file exists, then it will be truncated to zero size; otherwise, 340 * a new file will be created. The output will be written to the 341 * file and is buffered. 342 * 343 * @param csn 344 * The name of a supported {@linkplain java.nio.charset.Charset 345 * charset} 346 * 347 * @throws FileNotFoundException 348 * If the given file object does not denote an existing, writable 349 * regular file and a new regular file of that name cannot be 350 * created, or if some other error occurs while opening or 351 * creating the file 352 * 353 * @throws SecurityException 354 * If a security manager is present and {@link 355 * SecurityManager#checkWrite checkWrite(file.getPath())} 356 * denies write access to the file 357 * 358 * @throws UnsupportedEncodingException 359 * If the named charset is not supported 360 * 361 * @since 1.5 362 */ 363 public PrintStream(File file, String csn) 364 throws FileNotFoundException, UnsupportedEncodingException 365 { 366 // ensure charset is checked before the file is opened 367 this(false, toCharset(csn), new FileOutputStream(file)); 368 } 369 370 371 /** 372 * Creates a new print stream, without automatic line flushing, with the 373 * specified file and charset. This convenience constructor creates 374 * the necessary intermediate {@link java.io.OutputStreamWriter 375 * OutputStreamWriter}, which will encode characters using the provided 376 * charset. 377 * 378 * @param file 379 * The file to use as the destination of this print stream. If the 380 * file exists, then it will be truncated to zero size; otherwise, 381 * a new file will be created. The output will be written to the 382 * file and is buffered. 383 * 384 * @param charset 385 * A {@linkplain java.nio.charset.Charset charset} 386 * 387 * @throws IOException 388 * if an I/O error occurs while opening or creating the file 389 * 390 * @throws SecurityException 391 * If a security manager is present and {@link 392 * SecurityManager#checkWrite checkWrite(file.getPath())} 393 * denies write access to the file 394 * 395 * @since 10 396 */ 397 public PrintStream(File file, Charset charset) throws IOException { 398 this(false, requireNonNull(charset, "charset"), new FileOutputStream(file)); 399 } 400 401 /** Check to make sure that the stream has not been closed */ 402 private void ensureOpen() throws IOException { 403 if (out == null) 404 throw new IOException("Stream closed"); 405 } 406 407 /** 408 * Flushes the stream. This is done by writing any buffered output bytes to 409 * the underlying output stream and then flushing that stream. 410 * 411 * @see java.io.OutputStream#flush() 412 */ 413 public void flush() { 414 synchronized (this) { 415 try { 416 ensureOpen(); 417 out.flush(); 418 } 419 catch (IOException x) { 420 trouble = true; 421 } 422 } 423 } 424 425 private boolean closing = false; /* To avoid recursive closing */ 426 427 /** 428 * Closes the stream. This is done by flushing the stream and then closing 429 * the underlying output stream. 430 * 431 * @see java.io.OutputStream#close() 432 */ 433 public void close() { 434 synchronized (this) { 435 if (! closing) { 436 closing = true; 437 try { 438 textOut.close(); 439 out.close(); 440 } 441 catch (IOException x) { 442 trouble = true; 443 } 444 textOut = null; 445 charOut = null; 446 out = null; 447 } 448 } 449 } 450 451 /** 452 * Flushes the stream and checks its error state. The internal error state 453 * is set to {@code true} when the underlying output stream throws an 454 * {@code IOException} other than {@code InterruptedIOException}, 455 * and when the {@code setError} method is invoked. If an operation 456 * on the underlying output stream throws an 457 * {@code InterruptedIOException}, then the {@code PrintStream} 458 * converts the exception back into an interrupt by doing: 459 * <pre>{@code 460 * Thread.currentThread().interrupt(); 461 * }</pre> 462 * or the equivalent. 463 * 464 * @return {@code true} if and only if this stream has encountered an 465 * {@code IOException} other than 466 * {@code InterruptedIOException}, or the 467 * {@code setError} method has been invoked 468 */ 469 public boolean checkError() { 470 if (out != null) 471 flush(); 472 if (out instanceof java.io.PrintStream) { 473 PrintStream ps = (PrintStream) out; 474 return ps.checkError(); 475 } 476 return trouble; 477 } 478 479 /** 480 * Sets the error state of the stream to {@code true}. 481 * 482 * <p> This method will cause subsequent invocations of {@link 483 * #checkError()} to return {@code true} until 484 * {@link #clearError()} is invoked. 485 * 486 * @since 1.1 487 */ 488 protected void setError() { 489 trouble = true; 490 } 491 492 /** 493 * Clears the internal error state of this stream. 494 * 495 * <p> This method will cause subsequent invocations of {@link 496 * #checkError()} to return {@code false} until another write 497 * operation fails and invokes {@link #setError()}. 498 * 499 * @since 1.6 500 */ 501 protected void clearError() { 502 trouble = false; 503 } 504 505 /* 506 * Exception-catching, synchronized output operations, 507 * which also implement the write() methods of OutputStream 508 */ 509 510 /** 511 * Writes the specified byte to this stream. If the byte is a newline and 512 * automatic flushing is enabled then the {@code flush} method will be 513 * invoked. 514 * 515 * <p> Note that the byte is written as given; to write a character that 516 * will be translated according to the platform's default character 517 * encoding, use the {@code print(char)} or {@code println(char)} 518 * methods. 519 * 520 * @param b The byte to be written 521 * @see #print(char) 522 * @see #println(char) 523 */ 524 public void write(int b) { 525 try { 526 synchronized (this) { 527 ensureOpen(); 528 out.write(b); 529 if ((b == '\n') && autoFlush) 530 out.flush(); 531 } 532 } 533 catch (InterruptedIOException x) { 534 Thread.currentThread().interrupt(); 535 } 536 catch (IOException x) { 537 trouble = true; 538 } 539 } 540 541 /** 542 * Writes {@code len} bytes from the specified byte array starting at 543 * offset {@code off} to this stream. If automatic flushing is 544 * enabled then the {@code flush} method will be invoked. 545 * 546 * <p> Note that the bytes will be written as given; to write characters 547 * that will be translated according to the platform's default character 548 * encoding, use the {@code print(char)} or {@code println(char)} 549 * methods. 550 * 551 * @param buf A byte array 552 * @param off Offset from which to start taking bytes 553 * @param len Number of bytes to write 554 */ 555 public void write(byte buf[], int off, int len) { 556 try { 557 synchronized (this) { 558 ensureOpen(); 559 out.write(buf, off, len); 560 if (autoFlush) 561 out.flush(); 562 } 563 } 564 catch (InterruptedIOException x) { 565 Thread.currentThread().interrupt(); 566 } 567 catch (IOException x) { 568 trouble = true; 569 } 570 } 571 572 /* 573 * The following private methods on the text- and character-output streams 574 * always flush the stream buffers, so that writes to the underlying byte 575 * stream occur as promptly as with the original PrintStream. 576 */ 577 578 private void write(char[] buf) { 579 try { 580 synchronized (this) { 581 ensureOpen(); 582 textOut.write(buf); 583 textOut.flushBuffer(); 584 charOut.flushBuffer(); 585 if (autoFlush) { 586 for (int i = 0; i < buf.length; i++) 587 if (buf[i] == '\n') { 588 out.flush(); 589 break; 590 } 591 } 592 } 593 } catch (InterruptedIOException x) { 594 Thread.currentThread().interrupt(); 595 } catch (IOException x) { 596 trouble = true; 597 } 598 } 599 600 // Used to optimize away back-to-back flushing and synchronization when 601 // using println, but since subclasses could exist which depend on 602 // observing a call to print followed by newLine() we only use this if 603 // getClass() == PrintStream.class to avoid compatibility issues. 604 private void writeln(char[] buf) { 605 try { 606 synchronized (this) { 607 ensureOpen(); 608 textOut.write(buf); 609 textOut.newLine(); 610 textOut.flushBuffer(); 611 charOut.flushBuffer(); 612 if (autoFlush) 613 out.flush(); 614 } 615 } 616 catch (InterruptedIOException x) { 617 Thread.currentThread().interrupt(); 618 } 619 catch (IOException x) { 620 trouble = true; 621 } 622 } 623 624 private void write(String s) { 625 try { 626 synchronized (this) { 627 ensureOpen(); 628 textOut.write(s); 629 textOut.flushBuffer(); 630 charOut.flushBuffer(); 631 if (autoFlush && (s.indexOf('\n') >= 0)) 632 out.flush(); 633 } 634 } 635 catch (InterruptedIOException x) { 636 Thread.currentThread().interrupt(); 637 } 638 catch (IOException x) { 639 trouble = true; 640 } 641 } 642 643 // Used to optimize away back-to-back flushing and synchronization when 644 // using println, but since subclasses could exist which depend on 645 // observing a call to print followed by newLine we only use this if 646 // getClass() == PrintStream.class to avoid compatibility issues. 647 private void writeln(String s) { 648 try { 649 synchronized (this) { 650 ensureOpen(); 651 textOut.write(s); 652 textOut.newLine(); 653 textOut.flushBuffer(); 654 charOut.flushBuffer(); 655 if (autoFlush) 656 out.flush(); 657 } 658 } 659 catch (InterruptedIOException x) { 660 Thread.currentThread().interrupt(); 661 } 662 catch (IOException x) { 663 trouble = true; 664 } 665 } 666 667 private void newLine() { 668 try { 669 synchronized (this) { 670 ensureOpen(); 671 textOut.newLine(); 672 textOut.flushBuffer(); 673 charOut.flushBuffer(); 674 if (autoFlush) 675 out.flush(); 676 } 677 } 678 catch (InterruptedIOException x) { 679 Thread.currentThread().interrupt(); 680 } 681 catch (IOException x) { 682 trouble = true; 683 } 684 } 685 686 /* Methods that do not terminate lines */ 687 688 /** 689 * Prints a boolean value. The string produced by {@link 690 * java.lang.String#valueOf(boolean)} is translated into bytes 691 * according to the platform's default character encoding, and these bytes 692 * are written in exactly the manner of the 693 * {@link #write(int)} method. 694 * 695 * @param b The {@code boolean} to be printed 696 */ 697 public void print(boolean b) { 698 write(String.valueOf(b)); 699 } 700 701 /** 702 * Prints a character. The character is translated into one or more bytes 703 * according to the platform's default character encoding, and these bytes 704 * are written in exactly the manner of the 705 * {@link #write(int)} method. 706 * 707 * @param c The {@code char} to be printed 708 */ 709 public void print(char c) { 710 write(String.valueOf(c)); 711 } 712 713 /** 714 * Prints an integer. The string produced by {@link 715 * java.lang.String#valueOf(int)} is translated into bytes 716 * according to the platform's default character encoding, and these bytes 717 * are written in exactly the manner of the 718 * {@link #write(int)} method. 719 * 720 * @param i The {@code int} to be printed 721 * @see java.lang.Integer#toString(int) 722 */ 723 public void print(int i) { 724 write(String.valueOf(i)); 725 } 726 727 /** 728 * Prints a long integer. The string produced by {@link 729 * java.lang.String#valueOf(long)} is translated into bytes 730 * according to the platform's default character encoding, and these bytes 731 * are written in exactly the manner of the 732 * {@link #write(int)} method. 733 * 734 * @param l The {@code long} to be printed 735 * @see java.lang.Long#toString(long) 736 */ 737 public void print(long l) { 738 write(String.valueOf(l)); 739 } 740 741 /** 742 * Prints a floating-point number. The string produced by {@link 743 * java.lang.String#valueOf(float)} is translated into bytes 744 * according to the platform's default character encoding, and these bytes 745 * are written in exactly the manner of the 746 * {@link #write(int)} method. 747 * 748 * @param f The {@code float} to be printed 749 * @see java.lang.Float#toString(float) 750 */ 751 public void print(float f) { 752 write(String.valueOf(f)); 753 } 754 755 /** 756 * Prints a double-precision floating-point number. The string produced by 757 * {@link java.lang.String#valueOf(double)} is translated into 758 * bytes according to the platform's default character encoding, and these 759 * bytes are written in exactly the manner of the {@link 760 * #write(int)} method. 761 * 762 * @param d The {@code double} to be printed 763 * @see java.lang.Double#toString(double) 764 */ 765 public void print(double d) { 766 write(String.valueOf(d)); 767 } 768 769 /** 770 * Prints an array of characters. The characters are converted into bytes 771 * according to the platform's default character encoding, and these bytes 772 * are written in exactly the manner of the 773 * {@link #write(int)} method. 774 * 775 * @param s The array of chars to be printed 776 * 777 * @throws NullPointerException If {@code s} is {@code null} 778 */ 779 public void print(char s[]) { 780 write(s); 781 } 782 783 /** 784 * Prints a string. If the argument is {@code null} then the string 785 * {@code "null"} is printed. Otherwise, the string's characters are 786 * converted into bytes according to the platform's default character 787 * encoding, and these bytes are written in exactly the manner of the 788 * {@link #write(int)} method. 789 * 790 * @param s The {@code String} to be printed 791 */ 792 public void print(String s) { 793 write(String.valueOf(s)); 794 } 795 796 /** 797 * Prints an object. The string produced by the {@link 798 * java.lang.String#valueOf(Object)} method is translated into bytes 799 * according to the platform's default character encoding, and these bytes 800 * are written in exactly the manner of the 801 * {@link #write(int)} method. 802 * 803 * @param obj The {@code Object} to be printed 804 * @see java.lang.Object#toString() 805 */ 806 public void print(Object obj) { 807 write(String.valueOf(obj)); 808 } 809 810 811 /* Methods that do terminate lines */ 812 813 /** 814 * Terminates the current line by writing the line separator string. The 815 * line separator string is defined by the system property 816 * {@code line.separator}, and is not necessarily a single newline 817 * character ({@code '\n'}). 818 */ 819 public void println() { 820 newLine(); 821 } 822 823 /** 824 * Prints a boolean and then terminate the line. This method behaves as 825 * though it invokes {@link #print(boolean)} and then 826 * {@link #println()}. 827 * 828 * @param x The {@code boolean} to be printed 829 */ 830 public void println(boolean x) { 831 if (getClass() == PrintStream.class) { 832 writeln(String.valueOf(x)); 833 } else { 834 synchronized (this) { 835 print(x); 836 newLine(); 837 } 838 } 839 } 840 841 /** 842 * Prints a character and then terminate the line. This method behaves as 843 * though it invokes {@link #print(char)} and then 844 * {@link #println()}. 845 * 846 * @param x The {@code char} to be printed. 847 */ 848 public void println(char x) { 849 if (getClass() == PrintStream.class) { 850 writeln(String.valueOf(x)); 851 } else { 852 synchronized (this) { 853 print(x); 854 newLine(); 855 } 856 } 857 } 858 859 /** 860 * Prints an integer and then terminate the line. This method behaves as 861 * though it invokes {@link #print(int)} and then 862 * {@link #println()}. 863 * 864 * @param x The {@code int} to be printed. 865 */ 866 public void println(int x) { 867 if (getClass() == PrintStream.class) { 868 writeln(String.valueOf(x)); 869 } else { 870 synchronized (this) { 871 print(x); 872 newLine(); 873 } 874 } 875 } 876 877 /** 878 * Prints a long and then terminate the line. This method behaves as 879 * though it invokes {@link #print(long)} and then 880 * {@link #println()}. 881 * 882 * @param x a The {@code long} to be printed. 883 */ 884 public void println(long x) { 885 if (getClass() == PrintStream.class) { 886 writeln(String.valueOf(x)); 887 } else { 888 synchronized (this) { 889 print(x); 890 newLine(); 891 } 892 } 893 } 894 895 /** 896 * Prints a float and then terminate the line. This method behaves as 897 * though it invokes {@link #print(float)} and then 898 * {@link #println()}. 899 * 900 * @param x The {@code float} to be printed. 901 */ 902 public void println(float x) { 903 if (getClass() == PrintStream.class) { 904 writeln(String.valueOf(x)); 905 } else { 906 synchronized (this) { 907 print(x); 908 newLine(); 909 } 910 } 911 } 912 913 /** 914 * Prints a double and then terminate the line. This method behaves as 915 * though it invokes {@link #print(double)} and then 916 * {@link #println()}. 917 * 918 * @param x The {@code double} to be printed. 919 */ 920 public void println(double x) { 921 if (getClass() == PrintStream.class) { 922 writeln(String.valueOf(x)); 923 } else { 924 synchronized (this) { 925 print(x); 926 newLine(); 927 } 928 } 929 } 930 931 /** 932 * Prints an array of characters and then terminate the line. This method 933 * behaves as though it invokes {@link #print(char[])} and 934 * then {@link #println()}. 935 * 936 * @param x an array of chars to print. 937 */ 938 public void println(char[] x) { 939 if (getClass() == PrintStream.class) { 940 writeln(x); 941 } else { 942 synchronized (this) { 943 print(x); 944 newLine(); 945 } 946 } 947 } 948 949 /** 950 * Prints a String and then terminate the line. This method behaves as 951 * though it invokes {@link #print(String)} and then 952 * {@link #println()}. 953 * 954 * @param x The {@code String} to be printed. 955 */ 956 public void println(String x) { 957 if (getClass() == PrintStream.class) { 958 writeln(String.valueOf(x)); 959 } else { 960 synchronized (this) { 961 print(x); 962 newLine(); 963 } 964 } 965 } 966 967 /** 968 * Prints an Object and then terminate the line. This method calls 969 * at first String.valueOf(x) to get the printed object's string value, 970 * then behaves as 971 * though it invokes {@link #print(String)} and then 972 * {@link #println()}. 973 * 974 * @param x The {@code Object} to be printed. 975 */ 976 public void println(Object x) { 977 String s = String.valueOf(x); 978 if (getClass() == PrintStream.class) { 979 // need to apply String.valueOf again since first invocation 980 // might return null 981 writeln(String.valueOf(s)); 982 } else { 983 synchronized (this) { 984 print(s); 985 newLine(); 986 } 987 } 988 } 989 990 991 /** 992 * A convenience method to write a formatted string to this output stream 993 * using the specified format string and arguments. 994 * 995 * <p> An invocation of this method of the form 996 * {@code out.printf(format, args)} behaves 997 * in exactly the same way as the invocation 998 * 999 * <pre>{@code 1000 * out.format(format, args) 1001 * }</pre> 1002 * 1003 * @param format 1004 * A format string as described in <a 1005 * href="../util/Formatter.html#syntax">Format string syntax</a> 1006 * 1007 * @param args 1008 * Arguments referenced by the format specifiers in the format 1009 * string. If there are more arguments than format specifiers, the 1010 * extra arguments are ignored. The number of arguments is 1011 * variable and may be zero. The maximum number of arguments is 1012 * limited by the maximum dimension of a Java array as defined by 1013 * <cite>The Java™ Virtual Machine Specification</cite>. 1014 * The behaviour on a 1015 * {@code null} argument depends on the <a 1016 * href="../util/Formatter.html#syntax">conversion</a>. 1017 * 1018 * @throws java.util.IllegalFormatException 1019 * If a format string contains an illegal syntax, a format 1020 * specifier that is incompatible with the given arguments, 1021 * insufficient arguments given the format string, or other 1022 * illegal conditions. For specification of all possible 1023 * formatting errors, see the <a 1024 * href="../util/Formatter.html#detail">Details</a> section of the 1025 * formatter class specification. 1026 * 1027 * @throws NullPointerException 1028 * If the {@code format} is {@code null} 1029 * 1030 * @return This output stream 1031 * 1032 * @since 1.5 1033 */ 1034 public PrintStream printf(String format, Object ... args) { 1035 return format(format, args); 1036 } 1037 1038 /** 1039 * A convenience method to write a formatted string to this output stream 1040 * using the specified format string and arguments. 1041 * 1042 * <p> An invocation of this method of the form 1043 * {@code out.printf(l, format, args)} behaves 1044 * in exactly the same way as the invocation 1045 * 1046 * <pre>{@code 1047 * out.format(l, format, args) 1048 * }</pre> 1049 * 1050 * @param l 1051 * The {@linkplain java.util.Locale locale} to apply during 1052 * formatting. If {@code l} is {@code null} then no localization 1053 * is applied. 1054 * 1055 * @param format 1056 * A format string as described in <a 1057 * href="../util/Formatter.html#syntax">Format string syntax</a> 1058 * 1059 * @param args 1060 * Arguments referenced by the format specifiers in the format 1061 * string. If there are more arguments than format specifiers, the 1062 * extra arguments are ignored. The number of arguments is 1063 * variable and may be zero. The maximum number of arguments is 1064 * limited by the maximum dimension of a Java array as defined by 1065 * <cite>The Java™ Virtual Machine Specification</cite>. 1066 * The behaviour on a 1067 * {@code null} argument depends on the <a 1068 * href="../util/Formatter.html#syntax">conversion</a>. 1069 * 1070 * @throws java.util.IllegalFormatException 1071 * If a format string contains an illegal syntax, a format 1072 * specifier that is incompatible with the given arguments, 1073 * insufficient arguments given the format string, or other 1074 * illegal conditions. For specification of all possible 1075 * formatting errors, see the <a 1076 * href="../util/Formatter.html#detail">Details</a> section of the 1077 * formatter class specification. 1078 * 1079 * @throws NullPointerException 1080 * If the {@code format} is {@code null} 1081 * 1082 * @return This output stream 1083 * 1084 * @since 1.5 1085 */ 1086 public PrintStream printf(Locale l, String format, Object ... args) { 1087 return format(l, format, args); 1088 } 1089 1090 /** 1091 * Writes a formatted string to this output stream using the specified 1092 * format string and arguments. 1093 * 1094 * <p> The locale always used is the one returned by {@link 1095 * java.util.Locale#getDefault(Locale.Category)} with 1096 * {@link java.util.Locale.Category#FORMAT FORMAT} category specified, 1097 * regardless of any previous invocations of other formatting methods on 1098 * this object. 1099 * 1100 * @param format 1101 * A format string as described in <a 1102 * href="../util/Formatter.html#syntax">Format string syntax</a> 1103 * 1104 * @param args 1105 * Arguments referenced by the format specifiers in the format 1106 * string. If there are more arguments than format specifiers, the 1107 * extra arguments are ignored. The number of arguments is 1108 * variable and may be zero. The maximum number of arguments is 1109 * limited by the maximum dimension of a Java array as defined by 1110 * <cite>The Java™ Virtual Machine Specification</cite>. 1111 * The behaviour on a 1112 * {@code null} argument depends on the <a 1113 * href="../util/Formatter.html#syntax">conversion</a>. 1114 * 1115 * @throws java.util.IllegalFormatException 1116 * If a format string contains an illegal syntax, a format 1117 * specifier that is incompatible with the given arguments, 1118 * insufficient arguments given the format string, or other 1119 * illegal conditions. For specification of all possible 1120 * formatting errors, see the <a 1121 * href="../util/Formatter.html#detail">Details</a> section of the 1122 * formatter class specification. 1123 * 1124 * @throws NullPointerException 1125 * If the {@code format} is {@code null} 1126 * 1127 * @return This output stream 1128 * 1129 * @since 1.5 1130 */ 1131 public PrintStream format(String format, Object ... args) { 1132 try { 1133 synchronized (this) { 1134 ensureOpen(); 1135 if ((formatter == null) 1136 || (formatter.locale() != 1137 Locale.getDefault(Locale.Category.FORMAT))) 1138 formatter = new Formatter((Appendable) this); 1139 formatter.format(Locale.getDefault(Locale.Category.FORMAT), 1140 format, args); 1141 } 1142 } catch (InterruptedIOException x) { 1143 Thread.currentThread().interrupt(); 1144 } catch (IOException x) { 1145 trouble = true; 1146 } 1147 return this; 1148 } 1149 1150 /** 1151 * Writes a formatted string to this output stream using the specified 1152 * format string and arguments. 1153 * 1154 * @param l 1155 * The {@linkplain java.util.Locale locale} to apply during 1156 * formatting. If {@code l} is {@code null} then no localization 1157 * is applied. 1158 * 1159 * @param format 1160 * A format string as described in <a 1161 * href="../util/Formatter.html#syntax">Format string syntax</a> 1162 * 1163 * @param args 1164 * Arguments referenced by the format specifiers in the format 1165 * string. If there are more arguments than format specifiers, the 1166 * extra arguments are ignored. The number of arguments is 1167 * variable and may be zero. The maximum number of arguments is 1168 * limited by the maximum dimension of a Java array as defined by 1169 * <cite>The Java™ Virtual Machine Specification</cite>. 1170 * The behaviour on a 1171 * {@code null} argument depends on the <a 1172 * href="../util/Formatter.html#syntax">conversion</a>. 1173 * 1174 * @throws java.util.IllegalFormatException 1175 * If a format string contains an illegal syntax, a format 1176 * specifier that is incompatible with the given arguments, 1177 * insufficient arguments given the format string, or other 1178 * illegal conditions. For specification of all possible 1179 * formatting errors, see the <a 1180 * href="../util/Formatter.html#detail">Details</a> section of the 1181 * formatter class specification. 1182 * 1183 * @throws NullPointerException 1184 * If the {@code format} is {@code null} 1185 * 1186 * @return This output stream 1187 * 1188 * @since 1.5 1189 */ 1190 public PrintStream format(Locale l, String format, Object ... args) { 1191 try { 1192 synchronized (this) { 1193 ensureOpen(); 1194 if ((formatter == null) 1195 || (formatter.locale() != l)) 1196 formatter = new Formatter(this, l); 1197 formatter.format(l, format, args); 1198 } 1199 } catch (InterruptedIOException x) { 1200 Thread.currentThread().interrupt(); 1201 } catch (IOException x) { 1202 trouble = true; 1203 } 1204 return this; 1205 } 1206 1207 /** 1208 * Appends the specified character sequence to this output stream. 1209 * 1210 * <p> An invocation of this method of the form {@code out.append(csq)} 1211 * behaves in exactly the same way as the invocation 1212 * 1213 * <pre>{@code 1214 * out.print(csq.toString()) 1215 * }</pre> 1216 * 1217 * <p> Depending on the specification of {@code toString} for the 1218 * character sequence {@code csq}, the entire sequence may not be 1219 * appended. For instance, invoking then {@code toString} method of a 1220 * character buffer will return a subsequence whose content depends upon 1221 * the buffer's position and limit. 1222 * 1223 * @param csq 1224 * The character sequence to append. If {@code csq} is 1225 * {@code null}, then the four characters {@code "null"} are 1226 * appended to this output stream. 1227 * 1228 * @return This output stream 1229 * 1230 * @since 1.5 1231 */ 1232 public PrintStream append(CharSequence csq) { 1233 print(String.valueOf(csq)); 1234 return this; 1235 } 1236 1237 /** 1238 * Appends a subsequence of the specified character sequence to this output 1239 * stream. 1240 * 1241 * <p> An invocation of this method of the form 1242 * {@code out.append(csq, start, end)} when 1243 * {@code csq} is not {@code null}, behaves in 1244 * exactly the same way as the invocation 1245 * 1246 * <pre>{@code 1247 * out.print(csq.subSequence(start, end).toString()) 1248 * }</pre> 1249 * 1250 * @param csq 1251 * The character sequence from which a subsequence will be 1252 * appended. If {@code csq} is {@code null}, then characters 1253 * will be appended as if {@code csq} contained the four 1254 * characters {@code "null"}. 1255 * 1256 * @param start 1257 * The index of the first character in the subsequence 1258 * 1259 * @param end 1260 * The index of the character following the last character in the 1261 * subsequence 1262 * 1263 * @return This output stream 1264 * 1265 * @throws IndexOutOfBoundsException 1266 * If {@code start} or {@code end} are negative, {@code start} 1267 * is greater than {@code end}, or {@code end} is greater than 1268 * {@code csq.length()} 1269 * 1270 * @since 1.5 1271 */ 1272 public PrintStream append(CharSequence csq, int start, int end) { 1273 if (csq == null) csq = "null"; 1274 return append(csq.subSequence(start, end)); 1275 } 1276 1277 /** 1278 * Appends the specified character to this output stream. 1279 * 1280 * <p> An invocation of this method of the form {@code out.append(c)} 1281 * behaves in exactly the same way as the invocation 1282 * 1283 * <pre>{@code 1284 * out.print(c) 1285 * }</pre> 1286 * 1287 * @param c 1288 * The 16-bit character to append 1289 * 1290 * @return This output stream 1291 * 1292 * @since 1.5 1293 */ 1294 public PrintStream append(char c) { 1295 print(c); 1296 return this; 1297 } 1298 1299 }