Source for java.io.PrintStream

   1: /* PrintStream.java -- OutputStream for printing output
   2:    Copyright (C) 1998, 1999, 2001, 2003, 2004, 2005  Free Software Foundation, Inc.
   3: 
   4: This file is part of GNU Classpath.
   5: 
   6: GNU Classpath is free software; you can redistribute it and/or modify
   7: it under the terms of the GNU General Public License as published by
   8: the Free Software Foundation; either version 2, or (at your option)
   9: any later version.
  10:  
  11: GNU Classpath is distributed in the hope that it will be useful, but
  12: WITHOUT ANY WARRANTY; without even the implied warranty of
  13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14: General Public License for more details.
  15: 
  16: You should have received a copy of the GNU General Public License
  17: along with GNU Classpath; see the file COPYING.  If not, write to the
  18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19: 02110-1301 USA.
  20: 
  21: Linking this library statically or dynamically with other modules is
  22: making a combined work based on this library.  Thus, the terms and
  23: conditions of the GNU General Public License cover the whole
  24: combination.
  25: 
  26: As a special exception, the copyright holders of this library give you
  27: permission to link this library with independent modules to produce an
  28: executable, regardless of the license terms of these independent
  29: modules, and to copy and distribute the resulting executable under
  30: terms of your choice, provided that you also meet, for each linked
  31: independent module, the terms and conditions of the license of that
  32: module.  An independent module is a module which is not derived from
  33: or based on this library.  If you modify this library, you may extend
  34: this exception to your version of the library, but you are not
  35: obligated to do so.  If you do not wish to do so, delete this
  36: exception statement from your version. */
  37: 
  38: 
  39: package java.io;
  40: 
  41: import gnu.gcj.convert.UnicodeToBytes;
  42: 
  43: /* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
  44:  * "The Java Language Specification", ISBN 0-201-63451-1
  45:  * Status:  Believed complete and correct to 1.3
  46:  */
  47: 
  48: /**
  49:  * This class prints Java primitive values and object to a stream as
  50:  * text.  None of the methods in this class throw an exception.  However,
  51:  * errors can be detected by calling the <code>checkError()</code> method.
  52:  * Additionally, this stream can be designated as "autoflush" when 
  53:  * created so that any writes are automatically flushed to the underlying
  54:  * output sink when the current line is terminated.
  55:  * <p>
  56:  * This class converts char's into byte's using the system default encoding.
  57:  *
  58:  * @author Aaron M. Renn (arenn@urbanophile.com)
  59:  * @author Tom Tromey (tromey@cygnus.com)
  60:  */
  61: public class PrintStream extends FilterOutputStream
  62: {
  63:   /* Notice the implementation is quite similar to OutputStreamWriter.
  64:    * This leads to some minor duplication, because neither inherits
  65:    * from the other, and we want to maximize performance. */
  66: 
  67:   // Line separator string.
  68:   private static final char[] line_separator
  69:     = System.getProperty("line.separator").toCharArray();
  70:   
  71:   UnicodeToBytes converter;
  72: 
  73:   // Work buffer of characters for converter.
  74:   char[] work = new char[100];
  75:   // Work buffer of bytes where we temporarily keep converter output.
  76:   byte[] work_bytes = new byte[100];
  77: 
  78:   /**
  79:    * This boolean indicates whether or not an error has ever occurred
  80:    * on this stream.
  81:    */
  82:   private boolean error_occurred = false;
  83: 
  84:   /**
  85:    * This is <code>true</code> if auto-flush is enabled, 
  86:    * <code>false</code> otherwise
  87:    */
  88:   private boolean auto_flush;
  89: 
  90:   /**
  91:    * This method intializes a new <code>PrintStream</code> object to write
  92:    * to the specified output sink.
  93:    *
  94:    * @param out The <code>OutputStream</code> to write to.
  95:    */
  96:   public PrintStream (OutputStream out)
  97:   {
  98:     this (out, false);
  99:   }
 100: 
 101:   /**
 102:    * This method intializes a new <code>PrintStream</code> object to write
 103:    * to the specified output sink.  This constructor also allows "auto-flush"
 104:    * functionality to be specified where the stream will be flushed after
 105:    * every <code>print</code> or <code>println</code> call, when the 
 106:    * <code>write</code> methods with array arguments are called, or when a 
 107:    * single new-line character is written.
 108:    * <p>
 109:    *
 110:    * @param out The <code>OutputStream</code> to write to.
 111:    * @param auto_flush <code>true</code> to flush the stream after every 
 112:    * line, <code>false</code> otherwise
 113:    */
 114:   public PrintStream (OutputStream out, boolean auto_flush)
 115:   {
 116:     super (out);
 117: 
 118:     converter = UnicodeToBytes.getDefaultEncoder();
 119:     this.auto_flush = auto_flush;
 120:   }
 121: 
 122:   /**
 123:    * This method intializes a new <code>PrintStream</code> object to write
 124:    * to the specified output sink.  This constructor also allows "auto-flush"
 125:    * functionality to be specified where the stream will be flushed after
 126:    * every <code>print</code> or <code>println</code> call, when the 
 127:    * <code>write</code> methods with array arguments are called, or when a 
 128:    * single new-line character is written.
 129:    * <p>
 130:    *
 131:    * @param out The <code>OutputStream</code> to write to.
 132:    * @param auto_flush <code>true</code> to flush the stream after every 
 133:    * line, <code>false</code> otherwise
 134:    * @param encoding The name of the character encoding to use for this
 135:    * object.
 136:    */
 137:   public PrintStream (OutputStream out, boolean auto_flush, String encoding)
 138:     throws UnsupportedEncodingException
 139:   {
 140:     super (out);
 141: 
 142:     converter = UnicodeToBytes.getEncoder (encoding);
 143:     this.auto_flush = auto_flush;
 144:   }
 145: 
 146:   /**
 147:    * This method checks to see if an error has occurred on this stream.  Note
 148:    * that once an error has occurred, this method will continue to report
 149:    * <code>true</code> forever for this stream.  Before checking for an
 150:    * error condition, this method flushes the stream.
 151:    *
 152:    * @return <code>true</code> if an error has occurred, 
 153:    * <code>false</code> otherwise
 154:    */
 155:   public boolean checkError ()
 156:   {
 157:     flush ();
 158:     return error_occurred;
 159:   }
 160: 
 161:   /**
 162:    * This method can be called by subclasses to indicate that an error
 163:    * has occurred and should be reported by <code>checkError</code>.
 164:    */
 165:   protected void setError ()
 166:   {
 167:     error_occurred = true;
 168:   }
 169: 
 170:   /**
 171:    * This method closes this stream and all underlying streams.
 172:    */
 173:   public void close ()
 174:   {
 175:     try
 176:       {
 177:     flush();
 178:     out.close();
 179:       }
 180:     catch (InterruptedIOException iioe)
 181:       {
 182:     Thread.currentThread().interrupt();
 183:       }
 184:     catch (IOException e)
 185:       {
 186:     setError ();
 187:       }
 188:   }
 189: 
 190:   /**
 191:    * This method flushes any buffered bytes to the underlying stream and
 192:    * then flushes that stream as well.
 193:    */
 194:   public void flush ()
 195:   {
 196:     try
 197:       {
 198:     out.flush();
 199:       }
 200:     catch (InterruptedIOException iioe)
 201:       {
 202:     Thread.currentThread().interrupt();
 203:       }
 204:     catch (IOException e)
 205:       {
 206:     setError ();
 207:       }
 208:   }
 209: 
 210:   private synchronized void print (String str, boolean println)
 211:   {
 212:     try
 213:       {
 214:         writeChars(str, 0, str.length());
 215:     if (println)
 216:       writeChars(line_separator, 0, line_separator.length);
 217:     if (auto_flush)
 218:       flush();
 219:       }
 220:     catch (InterruptedIOException iioe)
 221:       {
 222:     Thread.currentThread().interrupt();
 223:       }
 224:     catch (IOException e)
 225:       {
 226:     setError ();
 227:       }
 228:   }
 229: 
 230:   private synchronized void print (char[] chars, int pos, int len,
 231:                    boolean println)
 232:   {
 233:     try
 234:       {
 235:         writeChars(chars, pos, len);
 236:     if (println)
 237:       writeChars(line_separator, 0, line_separator.length);
 238:     if (auto_flush)
 239:       flush();
 240:       }
 241:     catch (InterruptedIOException iioe)
 242:       {
 243:     Thread.currentThread().interrupt();
 244:       }
 245:     catch (IOException e)
 246:       {
 247:     setError ();
 248:       }
 249:   }
 250: 
 251:   private void writeChars(char[] buf, int offset, int count)
 252:     throws IOException
 253:   {
 254:     while (count > 0 || converter.havePendingBytes())
 255:       {
 256:     converter.setOutput(work_bytes, 0);
 257:     int converted = converter.write(buf, offset, count);
 258:     offset += converted;
 259:     count -= converted;
 260:     out.write(work_bytes, 0, converter.count);
 261:       }
 262:   }
 263: 
 264:   private void writeChars(String str, int offset, int count)
 265:     throws IOException
 266:   {
 267:     while (count > 0 || converter.havePendingBytes())
 268:       {
 269:     converter.setOutput(work_bytes, 0);
 270:     int converted = converter.write(str, offset, count, work);
 271:     offset += converted;
 272:     count -= converted;
 273:     out.write(work_bytes, 0, converter.count);
 274:       }
 275:   }
 276: 
 277:   /**
 278:    * This methods prints a boolean value to the stream.  <code>true</code>
 279:    * values are printed as "true" and <code>false</code> values are printed
 280:    * as "false".
 281:    *
 282:    * @param bool The <code>boolean</code> value to print
 283:    */
 284:   public void print (boolean bool)
 285:   {
 286:     print(String.valueOf(bool), false);
 287:   }
 288: 
 289:   /**
 290:    * This method prints an integer to the stream.  The value printed is
 291:    * determined using the <code>String.valueOf()</code> method.
 292:    *
 293:    * @param inum The <code>int</code> value to be printed
 294:    */
 295:   public void print (int inum)
 296:   {
 297:     print(String.valueOf(inum), false);
 298:   }
 299: 
 300:   /**
 301:    * This method prints a long to the stream.  The value printed is
 302:    * determined using the <code>String.valueOf()</code> method.
 303:    *
 304:    * @param lnum The <code>long</code> value to be printed
 305:    */
 306:   public void print (long lnum)
 307:   {
 308:     print(String.valueOf(lnum), false);
 309:   }
 310: 
 311:   /**
 312:    * This method prints a float to the stream.  The value printed is
 313:    * determined using the <code>String.valueOf()</code> method.
 314:    *
 315:    * @param fnum The <code>float</code> value to be printed
 316:    */
 317:   public void print (float fnum)
 318:   {
 319:     print(String.valueOf(fnum), false);
 320:   }
 321: 
 322:   /**
 323:    * This method prints a double to the stream.  The value printed is
 324:    * determined using the <code>String.valueOf()</code> method.
 325:    *
 326:    * @param dnum The <code>double</code> value to be printed
 327:    */
 328:   public void print (double dnum)
 329:   {
 330:     print(String.valueOf(dnum), false);
 331:   }
 332: 
 333:   /**
 334:    * This method prints an <code>Object</code> to the stream.  The actual
 335:    * value printed is determined by calling the <code>String.valueOf()</code>
 336:    * method.
 337:    *
 338:    * @param obj The <code>Object</code> to print.
 339:    */
 340:   public void print (Object obj)
 341:   {
 342:     print(obj == null ? "null" : obj.toString(), false);
 343:   }
 344: 
 345:   /**
 346:    * This method prints a <code>String</code> to the stream.  The actual
 347:    * value printed depends on the system default encoding.
 348:    *
 349:    * @param str The <code>String</code> to print.
 350:    */
 351:   public void print (String str)
 352:   {
 353:     print(str == null ? "null" : str, false);
 354:   }
 355: 
 356:   /**
 357:    * This method prints a char to the stream.  The actual value printed is
 358:    * determined by the character encoding in use.
 359:    *
 360:    * @param ch The <code>char</code> value to be printed
 361:    */
 362:   public synchronized void print (char ch)
 363:   {
 364:     work[0] = ch;
 365:     print(work, 0, 1, false);
 366:   }
 367: 
 368:   /**
 369:    * This method prints an array of characters to the stream.  The actual
 370:    * value printed depends on the system default encoding.
 371:    *
 372:    * @param charArray The array of characters to print.
 373:    */
 374:   public void print (char[] charArray)
 375:   {
 376:     print(charArray, 0, charArray.length, false);
 377:   }
 378: 
 379:   /**
 380:    * This method prints a line separator sequence to the stream.  The value
 381:    * printed is determined by the system property <xmp>line.separator</xmp>
 382:    * and is not necessarily the Unix '\n' newline character.
 383:    */
 384:   public void println ()
 385:   {
 386:     print(line_separator, 0, line_separator.length, false);
 387:   }
 388: 
 389:   /**
 390:    * This methods prints a boolean value to the stream.  <code>true</code>
 391:    * values are printed as "true" and <code>false</code> values are printed
 392:    * as "false".
 393:    * <p>
 394:    * This method prints a line termination sequence after printing the value.
 395:    *
 396:    * @param bool The <code>boolean</code> value to print
 397:    */
 398:   public void println (boolean bool)
 399:   {
 400:     print(String.valueOf(bool), true);
 401:   }
 402: 
 403:   /**
 404:    * This method prints an integer to the stream.  The value printed is
 405:    * determined using the <code>String.valueOf()</code> method.
 406:    * <p>
 407:    * This method prints a line termination sequence after printing the value.
 408:    *
 409:    * @param inum The <code>int</code> value to be printed
 410:    */
 411:   public void println (int inum)
 412:   {
 413:     print(String.valueOf(inum), true);
 414:   }
 415: 
 416:   /**
 417:    * This method prints a long to the stream.  The value printed is
 418:    * determined using the <code>String.valueOf()</code> method.
 419:    * <p>
 420:    * This method prints a line termination sequence after printing the value.
 421:    *
 422:    * @param lnum The <code>long</code> value to be printed
 423:    */
 424:   public void println (long lnum)
 425:   {
 426:     print(String.valueOf(lnum), true);
 427:   }
 428: 
 429:   /**
 430:    * This method prints a float to the stream.  The value printed is
 431:    * determined using the <code>String.valueOf()</code> method.
 432:    * <p>
 433:    * This method prints a line termination sequence after printing the value.
 434:    *
 435:    * @param fnum The <code>float</code> value to be printed
 436:    */
 437:   public void println (float fnum)
 438:   {
 439:     print(String.valueOf(fnum), true);
 440:   }
 441: 
 442:   /**
 443:    * This method prints a double to the stream.  The value printed is
 444:    * determined using the <code>String.valueOf()</code> method.
 445:    * <p>
 446:    * This method prints a line termination sequence after printing the value.
 447:    *
 448:    * @param dnum The <code>double</code> value to be printed
 449:    */
 450:   public void println (double dnum)
 451:   {
 452:     print(String.valueOf(dnum), true);
 453:   }
 454: 
 455:   /**
 456:    * This method prints an <code>Object</code> to the stream.  The actual
 457:    * value printed is determined by calling the <code>String.valueOf()</code>
 458:    * method.
 459:    * <p>
 460:    * This method prints a line termination sequence after printing the value.
 461:    *
 462:    * @param obj The <code>Object</code> to print.
 463:    */
 464:   public void println (Object obj)
 465:   {
 466:     print(obj == null ? "null" : obj.toString(), true);
 467:   }
 468: 
 469:   /**
 470:    * This method prints a <code>String</code> to the stream.  The actual
 471:    * value printed depends on the system default encoding.
 472:    * <p>
 473:    * This method prints a line termination sequence after printing the value.
 474:    *
 475:    * @param str The <code>String</code> to print.
 476:    */
 477:   public void println (String str)
 478:   {
 479:     print (str == null ? "null" : str, true);
 480:   }
 481: 
 482:   /**
 483:    * This method prints a char to the stream.  The actual value printed is
 484:    * determined by the character encoding in use.
 485:    * <p>
 486:    * This method prints a line termination sequence after printing the value.
 487:    *
 488:    * @param ch The <code>char</code> value to be printed
 489:    */
 490:   public synchronized void println (char ch)
 491:   {
 492:     work[0] = ch;
 493:     print(work, 0, 1, true);
 494:   }
 495: 
 496:   /**
 497:    * This method prints an array of characters to the stream.  The actual
 498:    * value printed depends on the system default encoding.
 499:    * <p>
 500:    * This method prints a line termination sequence after printing the value.
 501:    *
 502:    * @param charArray The array of characters to print.
 503:    */
 504:   public void println (char[] charArray)
 505:   {
 506:     print(charArray, 0, charArray.length, true);
 507:   }
 508: 
 509:   /**
 510:    * This method writes a byte of data to the stream.  If auto-flush is
 511:    * enabled, printing a newline character will cause the stream to be
 512:    * flushed after the character is written.
 513:    * 
 514:    * @param oneByte The byte to be written
 515:    */
 516:   public void write (int oneByte)
 517:   {
 518:     try
 519:       {
 520:         out.write (oneByte & 0xff);
 521:         
 522:         if (auto_flush && (oneByte == '\n'))
 523:           flush ();
 524:       }
 525:     catch (InterruptedIOException iioe)
 526:       {
 527:     Thread.currentThread ().interrupt ();
 528:       }
 529:     catch (IOException e)
 530:       {
 531:         setError ();
 532:       }
 533:   }
 534: 
 535:   /**
 536:    * This method writes <code>len</code> bytes from the specified array
 537:    * starting at index <code>offset</code> into the array.
 538:    *
 539:    * @param buffer The array of bytes to write
 540:    * @param offset The index into the array to start writing from
 541:    * @param len The number of bytes to write
 542:    */
 543:   public void write (byte[] buffer, int offset, int len)
 544:   {
 545:     try
 546:       {
 547:         out.write (buffer, offset, len);
 548:         
 549:         if (auto_flush)
 550:           flush ();
 551:       }
 552:     catch (InterruptedIOException iioe)
 553:       {
 554:     Thread.currentThread ().interrupt ();
 555:       }
 556:     catch (IOException e)
 557:       {
 558:         setError ();
 559:       }
 560:   }
 561: } // class PrintStream