Source for java.net.URI

   1: /* URI.java -- An URI class
   2:    Copyright (C) 2002, 2004, 2005, 2006  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.net;
  40: 
  41: import java.io.IOException;
  42: import java.io.ObjectInputStream;
  43: import java.io.ObjectOutputStream;
  44: import java.io.Serializable;
  45: import java.util.regex.Matcher;
  46: import java.util.regex.Pattern;
  47: 
  48: /**
  49:  * <p>
  50:  * A URI instance represents that defined by 
  51:  * <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC3986</a>,
  52:  * with some deviations.
  53:  * </p>
  54:  * <p>
  55:  * At its highest level, a URI consists of:
  56:  * </p>
  57:  * <code>[<em>scheme</em><strong>:</strong>]<em>scheme-specific-part</em>
  58:  * [<strong>#</strong><em>fragment</em>]</code>
  59:  * </p>
  60:  * <p>
  61:  * where <strong>#</strong> and <strong>:</strong> are literal characters,
  62:  * and those parts enclosed in square brackets are optional.
  63:  * </p>
  64:  * <p>
  65:  * There are two main types of URI.  An <em>opaque</em> URI is one
  66:  * which just consists of the above three parts, and is not further
  67:  * defined.  An example of such a URI would be <em>mailto:</em> URI.
  68:  * In contrast, <em>hierarchical</em> URIs give further definition
  69:  * to the scheme-specific part, so as represent some part of a hierarchical
  70:  * structure.
  71:  * </p>
  72:  * <p>
  73:  * <code>[<strong>//</strong><em>authority</em>][<em>path</em>]
  74:  * [<strong>?</strong><em>query</em>]</code>
  75:  * </p>
  76:  * <p>
  77:  * with <strong>/</strong> and <strong>?</strong> being literal characters.
  78:  * When server-based, the authority section is further subdivided into:
  79:  * </p>
  80:  * <p>
  81:  * <code>[<em>user-info</em><strong>@</strong>]<em>host</em>
  82:  * [<strong>:</strong><em>port</em>]</code>
  83:  * </p>
  84:  * <p>
  85:  * with <strong>@</strong> and <strong>:</strong> as literal characters.
  86:  * Authority sections that are not server-based are said to be registry-based.
  87:  * </p>
  88:  * <p>
  89:  * Hierarchical URIs can be either relative or absolute.  Absolute URIs
  90:  * always start with a `<strong>/</strong>', while relative URIs don't
  91:  * specify a scheme.  Opaque URIs are always absolute.
  92:  * </p>
  93:  * <p>
  94:  * Each part of the URI may have one of three states: undefined, empty
  95:  * or containing some content.  The former two of these are represented
  96:  * by <code>null</code> and the empty string in Java, respectively.
  97:  * The scheme-specific part may never be undefined.  It also follows from
  98:  * this that the path sub-part may also not be undefined, so as to ensure
  99:  * the former.
 100:  * </p>
 101:  * <h2>Character Escaping and Quoting</h2>
 102:  * <p>
 103:  * The characters that can be used within a valid URI are restricted.
 104:  * There are two main classes of characters which can't be used as is
 105:  * within the URI:
 106:  * </p>
 107:  * <ol>
 108:  * <li><strong>Characters outside the US-ASCII character set</strong>.
 109:  * These have to be <strong>escaped</strong> in order to create
 110:  * an RFC-compliant URI; this means replacing the character with the
 111:  * appropriate hexadecimal value, preceded by a `%'.</li>
 112:  * <li><strong>Illegal characters</strong> (e.g. space characters,
 113:  * control characters) are quoted, which results in them being encoded
 114:  * in the same way as non-US-ASCII characters.</li>
 115:  * </ol>
 116:  * <p>
 117:  * The set of valid characters differs depending on the section of the URI:
 118:  * </p>
 119:  * <ul>
 120:  * <li><strong>Scheme</strong>: Must be an alphanumeric, `-', `.' or '+'.</li>
 121:  * <li><strong>Authority</strong>:Composed of the username, host, port, `@'
 122:  * and `:'.</li>
 123:  * <li><strong>Username</strong>: Allows unreserved or percent-encoded
 124:  * characters, sub-delimiters and `:'.</li>
 125:  * <li><strong>Host</strong>: Allows unreserved or percent-encoded
 126:  * characters, sub-delimiters and square brackets (`[' and `]') for IPv6
 127:  * addresses.</li>
 128:  * <li><strong>Port</strong>: Digits only.</li>
 129:  * <li><strong>Path</strong>: Allows the path characters and `/'.
 130:  * <li><strong>Query</strong>: Allows the path characters, `?' and '/'.
 131:  * <li><strong>Fragment</strong>: Allows the path characters, `?' and '/'.
 132:  * </ul>
 133:  * <p>
 134:  * These definitions reference the following sets of characters:
 135:  * </p>
 136:  * <ul>
 137:  * <li><strong>Unreserved characters</strong>: The alphanumerics plus
 138:  * `-', `.', `_', and `~'.</li>
 139:  * <li><strong>Sub-delimiters</strong>: `!', `$', `&', `(', `)', `*',
 140:  * `+', `,', `;', `=' and the single-quote itself.</li>
 141:  * <li><strong>Path characters</strong>: Unreserved and percent-encoded
 142:  * characters and the sub-delimiters along with `@' and `:'.</li>
 143:  * </ul>
 144:  * <p>
 145:  * The constructors and accessor methods allow the use and retrieval of
 146:  * URI components which contain non-US-ASCII characters directly.
 147:  * They are only escaped when the <code>toASCIIString()</code> method
 148:  * is used.  In contrast, illegal characters are always quoted, with the
 149:  * exception of the return values of the non-raw accessors.
 150:  * </p>
 151:  *
 152:  * @author Ito Kazumitsu (ito.kazumitsu@hitachi-cable.co.jp)
 153:  * @author Dalibor Topic (robilad@kaffe.org)
 154:  * @author Michael Koch (konqueror@gmx.de)
 155:  * @author Andrew John Hughes (gnu_andrew@member.fsf.org)
 156:  * @since 1.4
 157:  */
 158: public final class URI 
 159:   implements Comparable, Serializable
 160: {
 161:   /**
 162:    * For serialization compatability.
 163:    */
 164:   static final long serialVersionUID = -6052424284110960213L;
 165: 
 166:   /**
 167:    * Regular expression for parsing URIs.
 168:    *
 169:    * Taken from RFC 2396, Appendix B.
 170:    * This expression doesn't parse IPv6 addresses.
 171:    */
 172:   private static final String URI_REGEXP =
 173:     "^(([^:/?#]+):)?((//([^/?#]*))?([^?#]*)(\\?([^#]*))?)?(#(.*))?";
 174: 
 175:   /**
 176:    * Regular expression for parsing the authority segment.
 177:    */
 178:   private static final String AUTHORITY_REGEXP =
 179:     "(([^?#]*)@)?([^?#:]*)(:([0-9]*))?";
 180: 
 181:   /**
 182:    * Valid characters (taken from rfc2396/3986)
 183:    */
 184:   private static final String RFC2396_DIGIT = "0123456789";
 185:   private static final String RFC2396_LOWALPHA = "abcdefghijklmnopqrstuvwxyz";
 186:   private static final String RFC2396_UPALPHA = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 187:   private static final String RFC2396_ALPHA =
 188:     RFC2396_LOWALPHA + RFC2396_UPALPHA;
 189:   private static final String RFC2396_ALPHANUM = RFC2396_DIGIT + RFC2396_ALPHA;
 190:   private static final String RFC3986_UNRESERVED = RFC2396_ALPHANUM + "-._~";
 191:   private static final String RFC3986_SUBDELIMS = "!$&'()*+,;=";
 192:   private static final String RFC3986_REG_NAME =
 193:     RFC3986_UNRESERVED + RFC3986_SUBDELIMS + "%";
 194:   private static final String RFC3986_PCHAR = RFC3986_UNRESERVED + 
 195:     RFC3986_SUBDELIMS + ":@%";
 196:   private static final String RFC3986_SEGMENT = RFC3986_PCHAR;
 197:   private static final String RFC3986_PATH_SEGMENTS = RFC3986_SEGMENT + "/";
 198:   private static final String RFC3986_SSP = RFC3986_PCHAR + "?/";
 199:   private static final String RFC3986_HOST = RFC3986_REG_NAME + "[]";
 200:   private static final String RFC3986_USERINFO = RFC3986_REG_NAME + ":";
 201: 
 202:   /**
 203:    * Index of scheme component in parsed URI.
 204:    */
 205:   private static final int SCHEME_GROUP = 2;
 206: 
 207:   /**
 208:    * Index of scheme-specific-part in parsed URI.
 209:    */
 210:   private static final int SCHEME_SPEC_PART_GROUP = 3;
 211: 
 212:   /**
 213:    * Index of authority component in parsed URI.
 214:    */
 215:   private static final int AUTHORITY_GROUP = 5;
 216: 
 217:   /**
 218:    * Index of path component in parsed URI.
 219:    */
 220:   private static final int PATH_GROUP = 6;
 221: 
 222:   /**
 223:    * Index of query component in parsed URI.
 224:    */
 225:   private static final int QUERY_GROUP = 8;
 226: 
 227:   /**
 228:    * Index of fragment component in parsed URI.
 229:    */
 230:   private static final int FRAGMENT_GROUP = 10;
 231:   
 232:   /**
 233:    * Index of userinfo component in parsed authority section.
 234:    */
 235:   private static final int AUTHORITY_USERINFO_GROUP = 2;
 236: 
 237:   /**
 238:    * Index of host component in parsed authority section.
 239:    */
 240:   private static final int AUTHORITY_HOST_GROUP = 3;
 241: 
 242:   /**
 243:    * Index of port component in parsed authority section.
 244:    */
 245:   private static final int AUTHORITY_PORT_GROUP = 5;
 246: 
 247:   /**
 248:    * The compiled version of the URI regular expression.
 249:    */
 250:   private static final Pattern URI_PATTERN;
 251: 
 252:   /**
 253:    * The compiled version of the authority regular expression.
 254:    */
 255:   private static final Pattern AUTHORITY_PATTERN;
 256: 
 257:   /**
 258:    * The set of valid hexadecimal characters.
 259:    */
 260:   private static final String HEX = "0123456789ABCDEF";
 261: 
 262:   private transient String scheme;
 263:   private transient String rawSchemeSpecificPart;
 264:   private transient String schemeSpecificPart;
 265:   private transient String rawAuthority;
 266:   private transient String authority;
 267:   private transient String rawUserInfo;
 268:   private transient String userInfo;
 269:   private transient String rawHost;
 270:   private transient String host;
 271:   private transient int port = -1;
 272:   private transient String rawPath;
 273:   private transient String path;
 274:   private transient String rawQuery;
 275:   private transient String query;
 276:   private transient String rawFragment;
 277:   private transient String fragment;
 278:   private String string;
 279: 
 280:   /**
 281:    * Static initializer to pre-compile the regular expressions.
 282:    */
 283:   static
 284:   {
 285:     URI_PATTERN = Pattern.compile(URI_REGEXP);
 286:     AUTHORITY_PATTERN = Pattern.compile(AUTHORITY_REGEXP);
 287:   }
 288: 
 289:   private void readObject(ObjectInputStream is)
 290:     throws ClassNotFoundException, IOException
 291:   {
 292:     this.string = (String) is.readObject();
 293:     try
 294:       {
 295:     parseURI(this.string);
 296:       }
 297:     catch (URISyntaxException x)
 298:       {
 299:     // Should not happen.
 300:     throw new RuntimeException(x);
 301:       }
 302:   }
 303: 
 304:   private void writeObject(ObjectOutputStream os) throws IOException
 305:   {
 306:     if (string == null)
 307:       string = toString(); 
 308:     os.writeObject(string);
 309:   }
 310: 
 311:   /**
 312:    * <p>
 313:    * Returns the string content of the specified group of the supplied
 314:    * matcher.  The returned value is modified according to the following:
 315:    * </p>
 316:    * <ul>
 317:    * <li>If the resulting string has a length greater than 0, then
 318:    * that string is returned.</li>
 319:    * <li>If a string of zero length, is matched, then the content
 320:    * of the preceding group is considered.  If this is also an empty
 321:    * string, then <code>null</code> is returned to indicate an undefined
 322:    * value.  Otherwise, the value is truly the empty string and this is
 323:    * the returned value.</li>
 324:    * </ul>
 325:    * <p>
 326:    * This method is used for matching against all parts of the URI
 327:    * that may be either undefined or empty (i.e. all those but the
 328:    * scheme-specific part and the path).  In each case, the preceding
 329:    * group is the content of the original group, along with some
 330:    * additional distinguishing feature.  For example, the preceding
 331:    * group for the query includes the preceding question mark,
 332:    * while that of the fragment includes the hash symbol.  The presence
 333:    * of these features enables disambiguation between the two cases
 334:    * of a completely unspecified value and a simple non-existant value.
 335:    * The scheme differs in that it will never return an empty string;
 336:    * the delimiter follows the scheme rather than preceding it, so
 337:    * it becomes part of the following section.  The same is true
 338:    * of the user information.
 339:    * </p>
 340:    *
 341:    * @param match the matcher, which contains the results of the URI
 342:    *              matched against the URI regular expression.
 343:    * @return either the matched content, <code>null</code> for undefined
 344:    *         values, or an empty string for a URI part with empty content.
 345:    */
 346:   private static String getURIGroup(Matcher match, int group)
 347:   {
 348:     String matched = match.group(group);
 349:     if (matched == null || matched.length() == 0)
 350:       {
 351:     String prevMatched = match.group(group -1);
 352:     if (prevMatched == null || prevMatched.length() == 0)
 353:       return null;
 354:     else
 355:       return "";
 356:       }
 357:     return matched;
 358:   }
 359: 
 360:   /**
 361:    * Sets fields of this URI by parsing the given string.
 362:    *
 363:    * @param str The string to parse
 364:    *
 365:    * @exception URISyntaxException If the given string violates RFC 2396
 366:    */
 367:   private void parseURI(String str) throws URISyntaxException
 368:   {
 369:     Matcher matcher = URI_PATTERN.matcher(str);
 370:     
 371:     if (matcher.matches())
 372:       {
 373:     scheme = getURIGroup(matcher, SCHEME_GROUP);
 374:     rawSchemeSpecificPart = matcher.group(SCHEME_SPEC_PART_GROUP);
 375:     schemeSpecificPart = unquote(rawSchemeSpecificPart);
 376:     if (!isOpaque())
 377:       {
 378:         rawAuthority = getURIGroup(matcher, AUTHORITY_GROUP);
 379:         rawPath = matcher.group(PATH_GROUP);
 380:         rawQuery = getURIGroup(matcher, QUERY_GROUP);
 381:       }
 382:     rawFragment = getURIGroup(matcher, FRAGMENT_GROUP);
 383:       }
 384:     else
 385:       throw new URISyntaxException(str,
 386:                    "doesn't match URI regular expression");
 387:     parseServerAuthority();
 388: 
 389:     // We must eagerly unquote the parts, because this is the only time
 390:     // we may throw an exception.
 391:     authority = unquote(rawAuthority);
 392:     userInfo = unquote(rawUserInfo);
 393:     host = unquote(rawHost);
 394:     path = unquote(rawPath);
 395:     query = unquote(rawQuery);
 396:     fragment = unquote(rawFragment);
 397:   }
 398: 
 399:   /**
 400:    * Unquote "%" + hex quotes characters
 401:    *
 402:    * @param str The string to unquote or null.
 403:    *
 404:    * @return The unquoted string or null if str was null.
 405:    *
 406:    * @exception URISyntaxException If the given string contains invalid
 407:    * escape sequences.
 408:    */
 409:   private static String unquote(String str) throws URISyntaxException
 410:   {
 411:     if (str == null)
 412:       return null;
 413:     byte[] buf = new byte[str.length()];
 414:     int pos = 0;
 415:     for (int i = 0; i < str.length(); i++)
 416:       {
 417:     char c = str.charAt(i);
 418:     if (c == '%')
 419:       {
 420:         if (i + 2 >= str.length())
 421:           throw new URISyntaxException(str, "Invalid quoted character");
 422:         int hi = Character.digit(str.charAt(++i), 16);
 423:         int lo = Character.digit(str.charAt(++i), 16);
 424:         if (lo < 0 || hi < 0)
 425:           throw new URISyntaxException(str, "Invalid quoted character");
 426:         buf[pos++] = (byte) (hi * 16 + lo);
 427:       }
 428:     else
 429:       buf[pos++] = (byte) c;
 430:       }
 431:     try
 432:       {
 433:     return new String(buf, 0, pos, "utf-8");
 434:       }
 435:     catch (java.io.UnsupportedEncodingException x2)
 436:       {
 437:     throw (Error) new InternalError().initCause(x2);
 438:       }
 439:   }
 440: 
 441:   /**
 442:    * Quote characters illegal in URIs in given string.
 443:    *
 444:    * Replace illegal characters by encoding their UTF-8
 445:    * representation as "%" + hex code for each resulting
 446:    * UTF-8 character.
 447:    *
 448:    * @param str The string to quote
 449:    *
 450:    * @return The quoted string.
 451:    */
 452:   private static String quote(String str)
 453:   {
 454:     return quote(str, RFC3986_SSP);
 455:   }
 456: 
 457:   /**
 458:    * Quote characters illegal in URI authorities in given string.
 459:    *
 460:    * Replace illegal characters by encoding their UTF-8
 461:    * representation as "%" + hex code for each resulting
 462:    * UTF-8 character.
 463:    *
 464:    * @param str The string to quote
 465:    *
 466:    * @return The quoted string.
 467:    */
 468:   private static String quoteAuthority(String str)
 469:   {
 470:     // Technically, we should be using RFC2396_AUTHORITY, but
 471:     // it contains no additional characters.
 472:     return quote(str, RFC3986_REG_NAME);
 473:   }
 474: 
 475:   /**
 476:    * Quotes the characters in the supplied string that are not part of
 477:    * the specified set of legal characters.
 478:    *
 479:    * @param str the string to quote
 480:    * @param legalCharacters the set of legal characters
 481:    *
 482:    * @return the quoted string.
 483:    */
 484:   private static String quote(String str, String legalCharacters)
 485:   {
 486:     StringBuffer sb = new StringBuffer(str.length());
 487:     for (int i = 0; i < str.length(); i++)
 488:       {
 489:     char c = str.charAt(i);
 490:     if (legalCharacters.indexOf(c) == -1)
 491:       {
 492:         if (c <= 127)
 493:           {
 494:         sb.append('%');
 495:         sb.append(HEX.charAt(c / 16));
 496:         sb.append(HEX.charAt(c % 16));
 497:           }
 498:       }
 499:     else
 500:       sb.append(c);
 501:       }
 502:     return sb.toString();
 503:   }
 504: 
 505:   /**
 506:    * Quote characters illegal in URI hosts in given string.
 507:    *
 508:    * Replace illegal characters by encoding their UTF-8
 509:    * representation as "%" + hex code for each resulting
 510:    * UTF-8 character.
 511:    *
 512:    * @param str The string to quote
 513:    *
 514:    * @return The quoted string.
 515:    */
 516:   private static String quoteHost(String str)
 517:   {
 518:     return quote(str, RFC3986_HOST);
 519:   }
 520: 
 521:   /**
 522:    * Quote characters illegal in URI paths in given string.
 523:    *
 524:    * Replace illegal characters by encoding their UTF-8
 525:    * representation as "%" + hex code for each resulting
 526:    * UTF-8 character.
 527:    *
 528:    * @param str The string to quote
 529:    *
 530:    * @return The quoted string.
 531:    */
 532:   private static String quotePath(String str)
 533:   {
 534:     // Technically, we should be using RFC2396_PATH, but
 535:     // it contains no additional characters.
 536:     return quote(str, RFC3986_PATH_SEGMENTS);
 537:   }
 538: 
 539:   /**
 540:    * Quote characters illegal in URI user infos in given string.
 541:    *
 542:    * Replace illegal characters by encoding their UTF-8
 543:    * representation as "%" + hex code for each resulting
 544:    * UTF-8 character.
 545:    *
 546:    * @param str The string to quote
 547:    *
 548:    * @return The quoted string.
 549:    */
 550:   private static String quoteUserInfo(String str)
 551:   {
 552:     return quote(str, RFC3986_USERINFO);
 553:   }
 554: 
 555:   /**
 556:    * Creates an URI from the given string
 557:    *
 558:    * @param str The string to create the URI from
 559:    *
 560:    * @exception URISyntaxException If the given string violates RFC 2396
 561:    * @exception NullPointerException If str is null
 562:    */
 563:   public URI(String str) throws URISyntaxException
 564:   {
 565:     this.string = str;
 566:     parseURI(str);
 567:   }
 568: 
 569:   /**
 570:    * Create an URI from the given components
 571:    *
 572:    * @param scheme The scheme name
 573:    * @param userInfo The username and authorization info
 574:    * @param host The hostname
 575:    * @param port The port number
 576:    * @param path The path
 577:    * @param query The query
 578:    * @param fragment The fragment
 579:    *
 580:    * @exception URISyntaxException If the given string violates RFC 2396
 581:    */
 582:   public URI(String scheme, String userInfo, String host, int port,
 583:              String path, String query, String fragment)
 584:     throws URISyntaxException
 585:   {
 586:     this((scheme == null ? "" : scheme + ":")
 587:          + (userInfo == null && host == null && port == -1 ? "" : "//")
 588:          + (userInfo == null ? "" : quoteUserInfo(userInfo) + "@")
 589:          + (host == null ? "" : quoteHost(host))
 590:          + (port == -1 ? "" : ":" + String.valueOf(port))
 591:          + (path == null ? "" : quotePath(path))
 592:          + (query == null ? "" : "?" + quote(query))
 593:          + (fragment == null ? "" : "#" + quote(fragment)));
 594:   }
 595: 
 596:   /**
 597:    * Create an URI from the given components
 598:    *
 599:    * @param scheme The scheme name
 600:    * @param authority The authority
 601:    * @param path The apth
 602:    * @param query The query
 603:    * @param fragment The fragment
 604:    *
 605:    * @exception URISyntaxException If the given string violates RFC 2396
 606:    */
 607:   public URI(String scheme, String authority, String path, String query,
 608:              String fragment) throws URISyntaxException
 609:   {
 610:     this((scheme == null ? "" : scheme + ":")
 611:          + (authority == null ? "" : "//" + quoteAuthority(authority))
 612:          + (path == null ? "" : quotePath(path))
 613:          + (query == null ? "" : "?" + quote(query))
 614:          + (fragment == null ? "" : "#" + quote(fragment)));
 615:   }
 616: 
 617:   /**
 618:    * Create an URI from the given components
 619:    *
 620:    * @param scheme The scheme name
 621:    * @param host The hostname
 622:    * @param path The path
 623:    * @param fragment The fragment
 624:    *
 625:    * @exception URISyntaxException If the given string violates RFC 2396
 626:    */
 627:   public URI(String scheme, String host, String path, String fragment)
 628:     throws URISyntaxException
 629:   {
 630:     this(scheme, null, host, -1, path, null, fragment);
 631:   }
 632: 
 633:   /**
 634:    * Create an URI from the given components
 635:    *
 636:    * @param scheme The scheme name
 637:    * @param ssp The scheme specific part
 638:    * @param fragment The fragment
 639:    *
 640:    * @exception URISyntaxException If the given string violates RFC 2396
 641:    */
 642:   public URI(String scheme, String ssp, String fragment)
 643:     throws URISyntaxException
 644:   {
 645:     this((scheme == null ? "" : scheme + ":")
 646:          + (ssp == null ? "" : quote(ssp))
 647:          + (fragment == null ? "" : "#" + quote(fragment)));
 648:   }
 649: 
 650:   /**
 651:    * Create an URI from the given string
 652:    *
 653:    * @param str The string to create the URI from
 654:    *
 655:    * @exception IllegalArgumentException If the given string violates RFC 2396
 656:    * @exception NullPointerException If str is null
 657:    */
 658:   public static URI create(String str)
 659:   {
 660:     try
 661:       {
 662:     return new URI(str);
 663:       }
 664:     catch (URISyntaxException e)
 665:       {
 666:     throw (IllegalArgumentException) new IllegalArgumentException()
 667:           .initCause(e);
 668:       }
 669:   }
 670: 
 671:   /**
 672:    * Attempts to parse this URI's authority component, if defined,
 673:    * into user-information, host, and port components.  The purpose
 674:    * of this method was to disambiguate between some authority sections,
 675:    * which form invalid server-based authories, but valid registry
 676:    * based authorities.  In the updated RFC 3986, the authority section
 677:    * is defined differently, with registry-based authorities part of
 678:    * the host section.  Thus, this method is now simply an explicit
 679:    * way of parsing any authority section.
 680:    *
 681:    * @return the URI, with the authority section parsed into user
 682:    *         information, host and port components.
 683:    * @throws URISyntaxException if the given string violates RFC 2396
 684:    */
 685:   public URI parseServerAuthority() throws URISyntaxException
 686:   {
 687:     if (rawAuthority != null)
 688:       {
 689:     Matcher matcher = AUTHORITY_PATTERN.matcher(rawAuthority);
 690: 
 691:     if (matcher.matches())
 692:       {
 693:         rawUserInfo = getURIGroup(matcher, AUTHORITY_USERINFO_GROUP);
 694:         rawHost = getURIGroup(matcher, AUTHORITY_HOST_GROUP);
 695:         
 696:         String portStr = getURIGroup(matcher, AUTHORITY_PORT_GROUP);
 697:         
 698:         if (portStr != null)
 699:           try
 700:         {
 701:           port = Integer.parseInt(portStr);
 702:         }
 703:           catch (NumberFormatException e)
 704:         {
 705:           URISyntaxException use =
 706:             new URISyntaxException
 707:               (string, "doesn't match URI regular expression");
 708:           use.initCause(e);
 709:           throw use;
 710:         }
 711:       }
 712:     else
 713:       throw new URISyntaxException(string,
 714:                        "doesn't match URI regular expression");
 715:       }
 716:     return this;
 717:   }
 718: 
 719:   /**
 720:    * <p>
 721:    * Returns a normalized version of the URI.  If the URI is opaque,
 722:    * or its path is already in normal form, then this URI is simply
 723:    * returned.  Otherwise, the following transformation of the path
 724:    * element takes place:
 725:    * </p>
 726:    * <ol>
 727:    * <li>All `.' segments are removed.</li>
 728:    * <li>Each `..' segment which can be paired with a prior non-`..' segment
 729:    * is removed along with the preceding segment.</li>
 730:    * <li>A `.' segment is added to the front if the first segment contains
 731:    * a colon (`:').  This is a deviation from the RFC, which prevents
 732:    * confusion between the path and the scheme.</li>
 733:    * </ol>
 734:    * <p>
 735:    * The resulting URI will be free of `.' and `..' segments, barring those
 736:    * that were prepended or which couldn't be paired, respectively.
 737:    * </p>
 738:    *
 739:    * @return the normalized URI.
 740:    */
 741:   public URI normalize()
 742:   {
 743:     if (isOpaque() || path.indexOf("/./") == -1 && path.indexOf("/../") == -1)
 744:       return this;
 745:     try
 746:       {
 747:     return new URI(scheme, authority, normalizePath(path), query,
 748:                fragment);
 749:       }
 750:     catch (URISyntaxException e)
 751:       {
 752:     throw (Error) new InternalError("Normalized URI variant could not "+
 753:                     "be constructed").initCause(e);
 754:       }
 755:   }
 756: 
 757:   /**
 758:    * <p>
 759:    * Normalize the given path.  The following transformation takes place:
 760:    * </p>
 761:    * <ol>
 762:    * <li>All `.' segments are removed.</li>
 763:    * <li>Each `..' segment which can be paired with a prior non-`..' segment
 764:    * is removed along with the preceding segment.</li>
 765:    * <li>A `.' segment is added to the front if the first segment contains
 766:    * a colon (`:').  This is a deviation from the RFC, which prevents
 767:    * confusion between the path and the scheme.</li>
 768:    * </ol>
 769:    * <p>
 770:    * The resulting URI will be free of `.' and `..' segments, barring those
 771:    * that were prepended or which couldn't be paired, respectively.
 772:    * </p>
 773:    * 
 774:    * @param relativePath the relative path to be normalized.
 775:    * @return the normalized path.
 776:    */
 777:   private String normalizePath(String relativePath)
 778:   {
 779:     /* 
 780:        This follows the algorithm in section 5.2.4. of RFC3986,
 781:        but doesn't modify the input buffer.
 782:     */
 783:     StringBuffer input = new StringBuffer(relativePath);
 784:     StringBuffer output = new StringBuffer();
 785:     int start = 0;
 786:     while (start < input.length())
 787:       {
 788:     /* A */
 789:     if (input.indexOf("../",start) == start)
 790:       {
 791:         start += 3;
 792:         continue;
 793:       }
 794:     if (input.indexOf("./",start) == start)
 795:       {
 796:         start += 2;
 797:         continue;
 798:       }
 799:     /* B */
 800:     if (input.indexOf("/./",start) == start)
 801:       {
 802:         start += 2;
 803:         continue;
 804:       }
 805:     if (input.indexOf("/.",start) == start
 806:         && input.charAt(start + 2) != '.')
 807:       {
 808:         start += 1;
 809:         input.setCharAt(start,'/');
 810:         continue;
 811:       }
 812:     /* C */
 813:     if (input.indexOf("/../",start) == start)
 814:       {
 815:         start += 3;
 816:         removeLastSegment(output);
 817:         continue;
 818:       }
 819:     if (input.indexOf("/..",start) == start)
 820:       {
 821:         start += 2;
 822:         input.setCharAt(start,'/');
 823:         removeLastSegment(output);
 824:         continue;
 825:       }
 826:     /* D */
 827:     if (start == input.length() - 1 && input.indexOf(".",start) == start)
 828:       {
 829:         input.delete(0,1);
 830:         continue;
 831:       }
 832:     if (start == input.length() - 2 && input.indexOf("..",start) == start)
 833:       {
 834:         input.delete(0,2);
 835:         continue;
 836:       }
 837:     /* E */
 838:     int indexOfSlash = input.indexOf("/",start);
 839:     while (indexOfSlash == start)
 840:       {
 841:         output.append("/");
 842:         ++start;
 843:         indexOfSlash = input.indexOf("/",start);
 844:       }
 845:     if (indexOfSlash == -1)
 846:       indexOfSlash = input.length();
 847:     output.append(input.substring(start, indexOfSlash));
 848:         start = indexOfSlash;
 849:       }
 850:     return output.toString();
 851:   }
 852: 
 853:   /**
 854:    * Removes the last segment of the path from the specified buffer.
 855:    *
 856:    * @param buffer the buffer containing the path.
 857:    */
 858:   private void removeLastSegment(StringBuffer buffer)
 859:   {
 860:     int lastSlash = buffer.lastIndexOf("/");
 861:     if (lastSlash == -1)
 862:       buffer.setLength(0);
 863:     else
 864:       buffer.setLength(lastSlash);
 865:   }
 866: 
 867:   /**
 868:    * Resolves the given URI against this URI
 869:    *
 870:    * @param uri The URI to resolve against this URI
 871:    *
 872:    * @return The resulting URI, or null when it couldn't be resolved
 873:    * for some reason.
 874:    *
 875:    * @throws NullPointerException if uri is null
 876:    */
 877:   public URI resolve(URI uri)
 878:   {
 879:     if (uri.isAbsolute())
 880:       return uri;
 881:     if (uri.isOpaque())
 882:       return uri;
 883: 
 884:     String scheme = uri.getScheme();
 885:     String schemeSpecificPart = uri.getSchemeSpecificPart();
 886:     String authority = uri.getAuthority();
 887:     String path = uri.getPath();
 888:     String query = uri.getQuery();
 889:     String fragment = uri.getFragment();
 890: 
 891:     try
 892:       {
 893:     if (fragment != null && path != null && path.equals("")
 894:         && scheme == null && authority == null && query == null)
 895:       return new URI(this.scheme, this.schemeSpecificPart, fragment);
 896: 
 897:     if (authority == null)
 898:       {
 899:         authority = this.authority;
 900:         if (path == null)
 901:           path = "";
 902:         if (! (path.startsWith("/")))
 903:           {
 904:         StringBuffer basepath = new StringBuffer(this.path);
 905:         int i = this.path.lastIndexOf('/');
 906: 
 907:         if (i >= 0)
 908:           basepath.delete(i + 1, basepath.length());
 909: 
 910:         basepath.append(path);
 911:         path = normalizePath(basepath.toString());
 912:           }
 913:       }
 914:     return new URI(this.scheme, authority, path, query, fragment);
 915:       }
 916:     catch (URISyntaxException e)
 917:       {
 918:     throw (Error) new InternalError("Resolved URI variant could not "+
 919:                     "be constructed").initCause(e);
 920:       }
 921:   }
 922: 
 923:   /**
 924:    * Resolves the given URI string against this URI
 925:    *
 926:    * @param str The URI as string to resolve against this URI
 927:    *
 928:    * @return The resulting URI
 929:    *
 930:    * @throws IllegalArgumentException If the given URI string
 931:    * violates RFC 2396
 932:    * @throws NullPointerException If uri is null
 933:    */
 934:   public URI resolve(String str) throws IllegalArgumentException
 935:   {
 936:     return resolve(create(str));
 937:   }
 938: 
 939:   /**
 940:    * <p>
 941:    * Relativizes the given URI against this URI.  The following
 942:    * algorithm is used:
 943:    * </p>
 944:    * <ul>
 945:    * <li>If either URI is opaque, the given URI is returned.</li>
 946:    * <li>If the schemes of the URIs differ, the given URI is returned.</li>
 947:    * <li>If the authority components of the URIs differ, then the given
 948:    * URI is returned.</li>
 949:    * <li>If the path of this URI is not a prefix of the supplied URI,
 950:    * then the given URI is returned.</li>
 951:    * <li>If all the above conditions hold, a new URI is created using the
 952:    * query and fragment components of the given URI, along with a path
 953:    * computed by removing the path of this URI from the start of the path
 954:    * of the supplied URI.</li>
 955:    * </ul>
 956:    *
 957:    * @param uri the URI to relativize agsint this URI
 958:    * @return the resulting URI
 959:    * @throws NullPointerException if the uri is null
 960:    */
 961:   public URI relativize(URI uri)
 962:   {
 963:     if (isOpaque() || uri.isOpaque())
 964:       return uri;
 965:     if (scheme == null && uri.getScheme() != null)
 966:       return uri;
 967:     if (scheme != null && !(scheme.equals(uri.getScheme())))
 968:       return uri;
 969:     if (rawAuthority == null && uri.getRawAuthority() != null)
 970:       return uri;
 971:     if (rawAuthority != null && !(rawAuthority.equals(uri.getRawAuthority())))
 972:       return uri;
 973:     if (!(uri.getRawPath().startsWith(rawPath)))
 974:       return uri;
 975:     try
 976:       {
 977:     return new URI(null, null, 
 978:                uri.getRawPath().substring(rawPath.length()),
 979:                uri.getRawQuery(), uri.getRawFragment());
 980:       }
 981:     catch (URISyntaxException e)
 982:       {
 983:     throw (Error) new InternalError("Relativized URI variant could not "+
 984:                     "be constructed").initCause(e);       
 985:       }
 986:   }
 987: 
 988:   /**
 989:    * Creates an URL from an URI
 990:    *
 991:    * @throws MalformedURLException If a protocol handler for the URL could
 992:    * not be found, or if some other error occurred while constructing the URL
 993:    * @throws IllegalArgumentException If the URI is not absolute
 994:    */
 995:   public URL toURL() throws IllegalArgumentException, MalformedURLException
 996:   {
 997:     if (isAbsolute())
 998:       return new URL(this.toString());
 999: 
1000:     throw new IllegalArgumentException("not absolute");
1001:   }
1002: 
1003:   /**
1004:    * Returns the scheme of the URI
1005:    */
1006:   public String getScheme()
1007:   {
1008:     return scheme;
1009:   }
1010: 
1011:   /**
1012:    * Tells whether this URI is absolute or not
1013:    */
1014:   public boolean isAbsolute()
1015:   {
1016:     return scheme != null;
1017:   }
1018: 
1019:   /**
1020:    * Tell whether this URI is opaque or not
1021:    */
1022:   public boolean isOpaque()
1023:   {
1024:     return ((scheme != null) && ! (schemeSpecificPart.startsWith("/")));
1025:   }
1026: 
1027:   /**
1028:    * Returns the raw scheme specific part of this URI.
1029:    * The scheme-specific part is never undefined, though it may be empty
1030:    */
1031:   public String getRawSchemeSpecificPart()
1032:   {
1033:     return rawSchemeSpecificPart;
1034:   }
1035: 
1036:   /**
1037:    * Returns the decoded scheme specific part of this URI.
1038:    */
1039:   public String getSchemeSpecificPart()
1040:   {
1041:     return schemeSpecificPart;
1042:   }
1043: 
1044:   /**
1045:    * Returns the raw authority part of this URI
1046:    */
1047:   public String getRawAuthority()
1048:   {
1049:     return rawAuthority;
1050:   }
1051: 
1052:   /**
1053:    * Returns the decoded authority part of this URI
1054:    */
1055:   public String getAuthority()
1056:   {
1057:     return authority;
1058:   }
1059: 
1060:   /**
1061:    * Returns the raw user info part of this URI
1062:    */
1063:   public String getRawUserInfo()
1064:   {
1065:     return rawUserInfo;
1066:   }
1067: 
1068:   /**
1069:    * Returns the decoded user info part of this URI
1070:    */
1071:   public String getUserInfo()
1072:   {
1073:     return userInfo;
1074:   }
1075: 
1076:   /**
1077:    * Returns the hostname of the URI
1078:    */
1079:   public String getHost()
1080:   {
1081:     return host;
1082:   }
1083: 
1084:   /**
1085:    * Returns the port number of the URI
1086:    */
1087:   public int getPort()
1088:   {
1089:     return port;
1090:   }
1091: 
1092:   /**
1093:    * Returns the raw path part of this URI
1094:    */
1095:   public String getRawPath()
1096:   {
1097:     return rawPath;
1098:   }
1099: 
1100:   /**
1101:    * Returns the path of the URI
1102:    */
1103:   public String getPath()
1104:   {
1105:     return path;
1106:   }
1107: 
1108:   /**
1109:    * Returns the raw query part of this URI
1110:    */
1111:   public String getRawQuery()
1112:   {
1113:     return rawQuery;
1114:   }
1115: 
1116:   /**
1117:    * Returns the query of the URI
1118:    */
1119:   public String getQuery()
1120:   {
1121:     return query;
1122:   }
1123: 
1124:   /**
1125:    * Return the raw fragment part of this URI
1126:    */
1127:   public String getRawFragment()
1128:   {
1129:     return rawFragment;
1130:   }
1131: 
1132:   /**
1133:    * Returns the fragment of the URI
1134:    */
1135:   public String getFragment()
1136:   {
1137:     return fragment;
1138:   }
1139: 
1140:   /**
1141:    * <p> 
1142:    * Compares the URI with the given object for equality.  If the
1143:    * object is not a <code>URI</code>, then the method returns false.
1144:    * Otherwise, the following criteria are observed:
1145:    * </p>
1146:    * <ul>
1147:    * <li>The scheme of the URIs must either be null (undefined) in both cases,
1148:    * or equal, ignorant of case.</li>
1149:    * <li>The raw fragment of the URIs must either be null (undefined) in both
1150:    * cases, or equal, ignorant of case.</li>
1151:    * <li>Both URIs must be of the same type (opaque or hierarchial)</li>
1152:    * <li><strong>For opaque URIs:</strong></li>
1153:    * <ul>
1154:    * <li>The raw scheme-specific parts must be equal.</li>
1155:    * </ul>
1156:    * <li>For hierarchical URIs:</li>
1157:    * <ul>
1158:    * <li>The raw paths must be equal, ignorant of case.</li>
1159:    * <li>The raw queries are either both undefined or both equal, ignorant
1160:    * of case.</li>
1161:    * <li>The raw authority sections are either both undefined or:</li>
1162:    * <li><strong>For registry-based authorities:</strong></li>
1163:    * <ul><li>they are equal.</li></ul>
1164:    * <li><strong>For server-based authorities:</strong></li>
1165:    * <ul>
1166:    * <li>the hosts are equal, ignoring case</li>
1167:    * <li>the ports are equal</li>
1168:    * <li>the user information components are equal</li>
1169:    * </ul>
1170:    * </ul>
1171:    * </ul>
1172:    *
1173:    * @param obj the obj to compare the URI with.
1174:    * @return <code>true</code> if the objects are equal, according to
1175:    *         the specification above.
1176:    */
1177:   public boolean equals(Object obj)
1178:   {
1179:     if (!(obj instanceof URI))
1180:       return false;
1181:     URI uriObj = (URI) obj;
1182:     if (scheme == null)
1183:       {
1184:     if (uriObj.getScheme() != null)
1185:       return false;
1186:       }
1187:     else
1188:       if (!(scheme.equalsIgnoreCase(uriObj.getScheme())))
1189:     return false;
1190:     if (rawFragment == null)
1191:       {
1192:     if (uriObj.getRawFragment() != null)
1193:       return false;
1194:       }
1195:     else
1196:       if (!(rawFragment.equalsIgnoreCase(uriObj.getRawFragment())))
1197:     return false;
1198:     boolean opaqueThis = isOpaque();
1199:     boolean opaqueObj = uriObj.isOpaque();
1200:     if (opaqueThis && opaqueObj)
1201:       return rawSchemeSpecificPart.equals(uriObj.getRawSchemeSpecificPart());
1202:     else if (!opaqueThis && !opaqueObj)
1203:       {
1204:     boolean common = rawPath.equalsIgnoreCase(uriObj.getRawPath())
1205:       && ((rawQuery == null && uriObj.getRawQuery() == null)
1206:           || rawQuery.equalsIgnoreCase(uriObj.getRawQuery()));
1207:     if (rawAuthority == null && uriObj.getRawAuthority() == null)
1208:       return common;
1209:     if (host == null)
1210:       return common 
1211:         && rawAuthority.equalsIgnoreCase(uriObj.getRawAuthority());
1212:     return common 
1213:       && host.equalsIgnoreCase(uriObj.getHost())
1214:       && port == uriObj.getPort()
1215:       && (rawUserInfo == null ?
1216:           uriObj.getRawUserInfo() == null :
1217:           rawUserInfo.equalsIgnoreCase(uriObj.getRawUserInfo()));
1218:       }
1219:     else
1220:       return false;
1221:   }
1222: 
1223:   /**
1224:    * Computes the hashcode of the URI
1225:    */
1226:   public int hashCode()
1227:   {
1228:     return (getScheme() == null ? 0 : 13 * getScheme().hashCode())
1229:       + 17 * getRawSchemeSpecificPart().hashCode()
1230:       + (getRawFragment() == null ? 0 : 21 + getRawFragment().hashCode());
1231:   }
1232: 
1233:   /**
1234:    * Compare the URI with another object that must also be a URI.
1235:    * Undefined components are taken to be less than any other component.
1236:    * The following criteria are observed:
1237:    * </p>
1238:    * <ul>
1239:    * <li>Two URIs with different schemes are compared according to their
1240:    * scheme, regardless of case.</li>
1241:    * <li>A hierarchical URI is less than an opaque URI with the same
1242:    * scheme.</li>
1243:    * <li><strong>For opaque URIs:</strong></li>
1244:    * <ul>
1245:    * <li>URIs with differing scheme-specific parts are ordered according
1246:    * to the ordering of the scheme-specific part.</li>
1247:    * <li>URIs with the same scheme-specific part are ordered by the
1248:    * raw fragment.</li>
1249:    * </ul>
1250:    * <li>For hierarchical URIs:</li>
1251:    * <ul>
1252:    * <li>URIs are ordered according to their raw authority sections,
1253:    * if they are unequal.</li>
1254:    * <li><strong>For registry-based authorities:</strong></li>
1255:    * <ul><li>they are ordered according to the ordering of the authority
1256:    * component.</li></ul>
1257:    * <li><strong>For server-based authorities:</strong></li>
1258:    * <ul>
1259:    * <li>URIs are ordered according to the raw user information.</li>
1260:    * <li>URIs with the same user information are ordered by the host,
1261:    * ignoring case.</li>
1262:    * <lI>URIs with the same host are ordered by the port.</li>
1263:    * </ul>
1264:    * <li>URIs with the same authority section are ordered by the raw path.</li>
1265:    * <li>URIs with the same path are ordered by their raw query.</li>
1266:    * <li>URIs with the same query are ordered by their raw fragments.</li>
1267:    * </ul>
1268:    * </ul>
1269:    *
1270:    * @param obj This object to compare this URI with
1271:    * @return a negative integer, zero or a positive integer depending
1272:    *         on whether this URI is less than, equal to or greater
1273:    *         than that supplied, respectively.
1274:    * @throws ClassCastException if the given object is not a URI
1275:    */
1276:   public int compareTo(Object obj) 
1277:     throws ClassCastException
1278:   {
1279:     URI uri = (URI) obj;
1280:     if (scheme == null && uri.getScheme() != null)
1281:       return -1;
1282:     if (scheme != null)
1283:       {
1284:     int sCompare = scheme.compareToIgnoreCase(uri.getScheme()); 
1285:     if (sCompare != 0)
1286:       return sCompare;
1287:       }
1288:     boolean opaqueThis = isOpaque();
1289:     boolean opaqueObj = uri.isOpaque();
1290:     if (opaqueThis && !opaqueObj)
1291:       return 1;
1292:     if (!opaqueThis && opaqueObj)
1293:       return -1;
1294:     if (opaqueThis)
1295:       {
1296:     int ssCompare = 
1297:       rawSchemeSpecificPart.compareTo(uri.getRawSchemeSpecificPart());
1298:     if (ssCompare == 0)
1299:       return compareFragments(uri);
1300:     else
1301:       return ssCompare;
1302:       }
1303:     if (rawAuthority == null && uri.getRawAuthority() != null)
1304:       return -1;
1305:     if (rawAuthority != null)
1306:       {
1307:     int aCompare = rawAuthority.compareTo(uri.getRawAuthority());
1308:     if (aCompare != 0)
1309:       {
1310:         if (host == null)
1311:           return aCompare;
1312:         if (rawUserInfo == null && uri.getRawUserInfo() != null)
1313:           return -1;
1314:         int uCompare = rawUserInfo.compareTo(uri.getRawUserInfo());
1315:         if (uCompare != 0)
1316:           return uCompare;
1317:         if (host == null && uri.getHost() != null)
1318:           return -1;
1319:         int hCompare = host.compareTo(uri.getHost());
1320:         if (hCompare != 0)
1321:           return hCompare;
1322:         return new Integer(port).compareTo(new Integer(uri.getPort()));
1323:       }
1324:       }
1325:     if (rawPath == null && uri.getRawPath() != null)
1326:       return -1;
1327:     if (rawPath != null)
1328:       {
1329:     int pCompare = rawPath.compareTo(uri.getRawPath()); 
1330:     if (pCompare != 0)
1331:       return pCompare;
1332:       }
1333:     if (rawQuery == null && uri.getRawQuery() != null)
1334:       return -1;
1335:     if (rawQuery != null)
1336:       {
1337:     int qCompare = rawQuery.compareTo(uri.getRawQuery());
1338:     if (qCompare != 0)
1339:       return qCompare;
1340:       }
1341:     return compareFragments(uri);
1342:   }
1343: 
1344:   /**
1345:    * Compares the fragment of this URI with that of the supplied URI.
1346:    *
1347:    * @param uri the URI to compare with this one.
1348:    * @return a negative integer, zero or a positive integer depending
1349:    *         on whether this uri's fragment is less than, equal to
1350:    *         or greater than the fragment of the uri supplied, respectively.
1351:    */
1352:   private int compareFragments(URI uri)
1353:   {
1354:     if (rawFragment == null && uri.getRawFragment() != null)
1355:       return -1;
1356:     else if (rawFragment == null)
1357:       return 0;
1358:     else
1359:       return rawFragment.compareTo(uri.getRawFragment());
1360:   }
1361: 
1362:   /**
1363:    * Returns the URI as a String.  If the URI was created using a constructor,
1364:    * then this will be the same as the original input string.
1365:    *
1366:    * @return a string representation of the URI.
1367:    */
1368:   public String toString()
1369:   {
1370:     return (scheme == null ? "" : scheme + ":")
1371:       + rawSchemeSpecificPart
1372:       + (rawFragment == null ? "" : "#" + rawFragment);
1373:   }
1374: 
1375:   /**
1376:    * Returns the URI as US-ASCII string.  This is the same as the result
1377:    * from <code>toString()</code> for URIs that don't contain any non-US-ASCII
1378:    * characters.  Otherwise, the non-US-ASCII characters are replaced
1379:    * by their percent-encoded representations.
1380:    *
1381:    * @return a string representation of the URI, containing only US-ASCII
1382:    *         characters.
1383:    */
1384:   public String toASCIIString()
1385:   {
1386:     String strRep = toString();
1387:     boolean inNonAsciiBlock = false;
1388:     StringBuffer buffer = new StringBuffer();
1389:     StringBuffer encBuffer = null;
1390:     for (int i = 0; i < strRep.length(); i++)
1391:       {
1392:     char c = strRep.charAt(i);
1393:     if (c <= 127)
1394:       {
1395:         if (inNonAsciiBlock)
1396:           {
1397:         buffer.append(escapeCharacters(encBuffer.toString()));
1398:         inNonAsciiBlock = false;
1399:           }
1400:         buffer.append(c);
1401:       }
1402:     else
1403:       {
1404:         if (!inNonAsciiBlock)
1405:           {
1406:         encBuffer = new StringBuffer();
1407:         inNonAsciiBlock = true;
1408:           }
1409:         encBuffer.append(c);
1410:       }
1411:       }
1412:     return buffer.toString();
1413:   }
1414: 
1415:   /**
1416:    * Converts the non-ASCII characters in the supplied string
1417:    * to their equivalent percent-encoded representations.
1418:    * That is, they are replaced by "%" followed by their hexadecimal value.
1419:    *
1420:    * @param str a string including non-ASCII characters.
1421:    * @return the string with the non-ASCII characters converted to their
1422:    *         percent-encoded representations.
1423:    */
1424:   private static String escapeCharacters(String str)
1425:   {
1426:     try
1427:       {
1428:     StringBuffer sb = new StringBuffer(); 
1429:     // this is far from optimal, but it works
1430:     byte[] utf8 = str.getBytes("utf-8");
1431:     for (int j = 0; j < utf8.length; j++)
1432:       {
1433:         sb.append('%');
1434:         sb.append(HEX.charAt((utf8[j] & 0xff) / 16));
1435:         sb.append(HEX.charAt((utf8[j] & 0xff) % 16));
1436:       }
1437:     return sb.toString();
1438:       }
1439:     catch (java.io.UnsupportedEncodingException x)
1440:       {
1441:     throw (Error) new InternalError("Escaping error").initCause(x);
1442:       }
1443:   }
1444: 
1445: }