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<URI>, 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:         && (c <= 127))
 492:       {
 493:         sb.append('%');
 494:         sb.append(HEX.charAt(c / 16));
 495:         sb.append(HEX.charAt(c % 16));
 496:       }
 497:           else
 498:       sb.append(c);
 499:       }
 500:     return sb.toString();
 501:   }
 502: 
 503:   /**
 504:    * Quote characters illegal in URI hosts in given string.
 505:    *
 506:    * Replace illegal characters by encoding their UTF-8
 507:    * representation as "%" + hex code for each resulting
 508:    * UTF-8 character.
 509:    *
 510:    * @param str The string to quote
 511:    *
 512:    * @return The quoted string.
 513:    */
 514:   private static String quoteHost(String str)
 515:   {
 516:     return quote(str, RFC3986_HOST);
 517:   }
 518: 
 519:   /**
 520:    * Quote characters illegal in URI paths in given string.
 521:    *
 522:    * Replace illegal characters by encoding their UTF-8
 523:    * representation as "%" + hex code for each resulting
 524:    * UTF-8 character.
 525:    *
 526:    * @param str The string to quote
 527:    *
 528:    * @return The quoted string.
 529:    */
 530:   private static String quotePath(String str)
 531:   {
 532:     // Technically, we should be using RFC2396_PATH, but
 533:     // it contains no additional characters.
 534:     return quote(str, RFC3986_PATH_SEGMENTS);
 535:   }
 536: 
 537:   /**
 538:    * Quote characters illegal in URI user infos in given string.
 539:    *
 540:    * Replace illegal characters by encoding their UTF-8
 541:    * representation as "%" + hex code for each resulting
 542:    * UTF-8 character.
 543:    *
 544:    * @param str The string to quote
 545:    *
 546:    * @return The quoted string.
 547:    */
 548:   private static String quoteUserInfo(String str)
 549:   {
 550:     return quote(str, RFC3986_USERINFO);
 551:   }
 552: 
 553:   /**
 554:    * Creates an URI from the given string
 555:    *
 556:    * @param str The string to create the URI from
 557:    *
 558:    * @exception URISyntaxException If the given string violates RFC 2396
 559:    * @exception NullPointerException If str is null
 560:    */
 561:   public URI(String str) throws URISyntaxException
 562:   {
 563:     this.string = str;
 564:     parseURI(str);
 565:   }
 566: 
 567:   /**
 568:    * Create an URI from the given components
 569:    *
 570:    * @param scheme The scheme name
 571:    * @param userInfo The username and authorization info
 572:    * @param host The hostname
 573:    * @param port The port number
 574:    * @param path The path
 575:    * @param query The query
 576:    * @param fragment The fragment
 577:    *
 578:    * @exception URISyntaxException If the given string violates RFC 2396
 579:    */
 580:   public URI(String scheme, String userInfo, String host, int port,
 581:              String path, String query, String fragment)
 582:     throws URISyntaxException
 583:   {
 584:     this((scheme == null ? "" : scheme + ":")
 585:          + (userInfo == null && host == null && port == -1 ? "" : "//")
 586:          + (userInfo == null ? "" : quoteUserInfo(userInfo) + "@")
 587:          + (host == null ? "" : quoteHost(host))
 588:          + (port == -1 ? "" : ":" + String.valueOf(port))
 589:          + (path == null ? "" : quotePath(path))
 590:          + (query == null ? "" : "?" + quote(query))
 591:          + (fragment == null ? "" : "#" + quote(fragment)));
 592:   }
 593: 
 594:   /**
 595:    * Create an URI from the given components
 596:    *
 597:    * @param scheme The scheme name
 598:    * @param authority The authority
 599:    * @param path The apth
 600:    * @param query The query
 601:    * @param fragment The fragment
 602:    *
 603:    * @exception URISyntaxException If the given string violates RFC 2396
 604:    */
 605:   public URI(String scheme, String authority, String path, String query,
 606:              String fragment) throws URISyntaxException
 607:   {
 608:     this((scheme == null ? "" : scheme + ":")
 609:          + (authority == null ? "" : "//" + quoteAuthority(authority))
 610:          + (path == null ? "" : quotePath(path))
 611:          + (query == null ? "" : "?" + quote(query))
 612:          + (fragment == null ? "" : "#" + quote(fragment)));
 613:   }
 614: 
 615:   /**
 616:    * Create an URI from the given components
 617:    *
 618:    * @param scheme The scheme name
 619:    * @param host The hostname
 620:    * @param path The path
 621:    * @param fragment The fragment
 622:    *
 623:    * @exception URISyntaxException If the given string violates RFC 2396
 624:    */
 625:   public URI(String scheme, String host, String path, String fragment)
 626:     throws URISyntaxException
 627:   {
 628:     this(scheme, null, host, -1, path, null, fragment);
 629:   }
 630: 
 631:   /**
 632:    * Create an URI from the given components
 633:    *
 634:    * @param scheme The scheme name
 635:    * @param ssp The scheme specific part
 636:    * @param fragment The fragment
 637:    *
 638:    * @exception URISyntaxException If the given string violates RFC 2396
 639:    */
 640:   public URI(String scheme, String ssp, String fragment)
 641:     throws URISyntaxException
 642:   {
 643:     this((scheme == null ? "" : scheme + ":")
 644:          + (ssp == null ? "" : quote(ssp))
 645:          + (fragment == null ? "" : "#" + quote(fragment)));
 646:   }
 647: 
 648:   /**
 649:    * Create an URI from the given string
 650:    *
 651:    * @param str The string to create the URI from
 652:    *
 653:    * @exception IllegalArgumentException If the given string violates RFC 2396
 654:    * @exception NullPointerException If str is null
 655:    */
 656:   public static URI create(String str)
 657:   {
 658:     try
 659:       {
 660:     return new URI(str);
 661:       }
 662:     catch (URISyntaxException e)
 663:       {
 664:     throw (IllegalArgumentException) new IllegalArgumentException()
 665:           .initCause(e);
 666:       }
 667:   }
 668: 
 669:   /**
 670:    * Attempts to parse this URI's authority component, if defined,
 671:    * into user-information, host, and port components.  The purpose
 672:    * of this method was to disambiguate between some authority sections,
 673:    * which form invalid server-based authories, but valid registry
 674:    * based authorities.  In the updated RFC 3986, the authority section
 675:    * is defined differently, with registry-based authorities part of
 676:    * the host section.  Thus, this method is now simply an explicit
 677:    * way of parsing any authority section.
 678:    *
 679:    * @return the URI, with the authority section parsed into user
 680:    *         information, host and port components.
 681:    * @throws URISyntaxException if the given string violates RFC 2396
 682:    */
 683:   public URI parseServerAuthority() throws URISyntaxException
 684:   {
 685:     if (rawAuthority != null)
 686:       {
 687:     Matcher matcher = AUTHORITY_PATTERN.matcher(rawAuthority);
 688: 
 689:     if (matcher.matches())
 690:       {
 691:         rawUserInfo = getURIGroup(matcher, AUTHORITY_USERINFO_GROUP);
 692:         rawHost = getURIGroup(matcher, AUTHORITY_HOST_GROUP);
 693:         
 694:         String portStr = getURIGroup(matcher, AUTHORITY_PORT_GROUP);
 695:         
 696:         if (portStr != null && ! portStr.isEmpty())
 697:           try
 698:         {
 699:           port = Integer.parseInt(portStr);
 700:         }
 701:           catch (NumberFormatException e)
 702:         {
 703:           URISyntaxException use =
 704:             new URISyntaxException
 705:               (string, "doesn't match URI regular expression");
 706:           use.initCause(e);
 707:           throw use;
 708:         }
 709:       }
 710:     else
 711:       throw new URISyntaxException(string,
 712:                        "doesn't match URI regular expression");
 713:       }
 714:     return this;
 715:   }
 716: 
 717:   /**
 718:    * <p>
 719:    * Returns a normalized version of the URI.  If the URI is opaque,
 720:    * or its path is already in normal form, then this URI is simply
 721:    * returned.  Otherwise, the following transformation of the path
 722:    * element takes place:
 723:    * </p>
 724:    * <ol>
 725:    * <li>All `.' segments are removed.</li>
 726:    * <li>Each `..' segment which can be paired with a prior non-`..' segment
 727:    * is removed along with the preceding segment.</li>
 728:    * <li>A `.' segment is added to the front if the first segment contains
 729:    * a colon (`:').  This is a deviation from the RFC, which prevents
 730:    * confusion between the path and the scheme.</li>
 731:    * </ol>
 732:    * <p>
 733:    * The resulting URI will be free of `.' and `..' segments, barring those
 734:    * that were prepended or which couldn't be paired, respectively.
 735:    * </p>
 736:    *
 737:    * @return the normalized URI.
 738:    */
 739:   public URI normalize()
 740:   {
 741:     if (isOpaque() || path.indexOf("/./") == -1 && path.indexOf("/../") == -1)
 742:       return this;
 743:     try
 744:       {
 745:     return new URI(scheme, authority, normalizePath(path), query,
 746:                fragment);
 747:       }
 748:     catch (URISyntaxException e)
 749:       {
 750:     throw (Error) new InternalError("Normalized URI variant could not "+
 751:                     "be constructed").initCause(e);
 752:       }
 753:   }
 754: 
 755:   /**
 756:    * <p>
 757:    * Normalize the given path.  The following transformation takes place:
 758:    * </p>
 759:    * <ol>
 760:    * <li>All `.' segments are removed.</li>
 761:    * <li>Each `..' segment which can be paired with a prior non-`..' segment
 762:    * is removed along with the preceding segment.</li>
 763:    * <li>A `.' segment is added to the front if the first segment contains
 764:    * a colon (`:').  This is a deviation from the RFC, which prevents
 765:    * confusion between the path and the scheme.</li>
 766:    * </ol>
 767:    * <p>
 768:    * The resulting URI will be free of `.' and `..' segments, barring those
 769:    * that were prepended or which couldn't be paired, respectively.
 770:    * </p>
 771:    * 
 772:    * @param relativePath the relative path to be normalized.
 773:    * @return the normalized path.
 774:    */
 775:   private String normalizePath(String relativePath)
 776:   {
 777:     /* 
 778:        This follows the algorithm in section 5.2.4. of RFC3986,
 779:        but doesn't modify the input buffer.
 780:     */
 781:     StringBuffer input = new StringBuffer(relativePath);
 782:     StringBuffer output = new StringBuffer();
 783:     int start = 0;
 784:     while (start < input.length())
 785:       {
 786:     /* A */
 787:     if (input.indexOf("../",start) == start)
 788:       {
 789:         start += 3;
 790:         continue;
 791:       }
 792:     if (input.indexOf("./",start) == start)
 793:       {
 794:         start += 2;
 795:         continue;
 796:       }
 797:     /* B */
 798:     if (input.indexOf("/./",start) == start)
 799:       {
 800:         start += 2;
 801:         continue;
 802:       }
 803:     if (input.indexOf("/.",start) == start
 804:         && input.charAt(start + 2) != '.')
 805:       {
 806:         start += 1;
 807:         input.setCharAt(start,'/');
 808:         continue;
 809:       }
 810:     /* C */
 811:     if (input.indexOf("/../",start) == start)
 812:       {
 813:         start += 3;
 814:         removeLastSegment(output);
 815:         continue;
 816:       }
 817:     if (input.indexOf("/..",start) == start)
 818:       {
 819:         start += 2;
 820:         input.setCharAt(start,'/');
 821:         removeLastSegment(output);
 822:         continue;
 823:       }
 824:     /* D */
 825:     if (start == input.length() - 1 && input.indexOf(".",start) == start)
 826:       {
 827:         input.delete(0,1);
 828:         continue;
 829:       }
 830:     if (start == input.length() - 2 && input.indexOf("..",start) == start)
 831:       {
 832:         input.delete(0,2);
 833:         continue;
 834:       }
 835:     /* E */
 836:     int indexOfSlash = input.indexOf("/",start);
 837:     while (indexOfSlash == start)
 838:       {
 839:         output.append("/");
 840:         ++start;
 841:         indexOfSlash = input.indexOf("/",start);
 842:       }
 843:     if (indexOfSlash == -1)
 844:       indexOfSlash = input.length();
 845:     output.append(input.substring(start, indexOfSlash));
 846:         start = indexOfSlash;
 847:       }
 848:     return output.toString();
 849:   }
 850: 
 851:   /**
 852:    * Removes the last segment of the path from the specified buffer.
 853:    *
 854:    * @param buffer the buffer containing the path.
 855:    */
 856:   private void removeLastSegment(StringBuffer buffer)
 857:   {
 858:     int lastSlash = buffer.lastIndexOf("/");
 859:     if (lastSlash == -1)
 860:       buffer.setLength(0);
 861:     else
 862:       buffer.setLength(lastSlash);
 863:   }
 864: 
 865:   /**
 866:    * Resolves the given URI against this URI
 867:    *
 868:    * @param uri The URI to resolve against this URI
 869:    *
 870:    * @return The resulting URI, or null when it couldn't be resolved
 871:    * for some reason.
 872:    *
 873:    * @throws NullPointerException if uri is null
 874:    */
 875:   public URI resolve(URI uri)
 876:   {
 877:     if (uri.isAbsolute())
 878:       return uri;
 879:     if (uri.isOpaque())
 880:       return uri;
 881: 
 882:     String scheme = uri.getScheme();
 883:     String schemeSpecificPart = uri.getSchemeSpecificPart();
 884:     String authority = uri.getAuthority();
 885:     String path = uri.getPath();
 886:     String query = uri.getQuery();
 887:     String fragment = uri.getFragment();
 888: 
 889:     try
 890:       {
 891:     if (fragment != null && path != null && path.equals("")
 892:         && scheme == null && authority == null && query == null)
 893:       return new URI(this.scheme, this.schemeSpecificPart, fragment);
 894: 
 895:     if (authority == null)
 896:       {
 897:         authority = this.authority;
 898:         if (path == null)
 899:           path = "";
 900:         if (! (path.startsWith("/")))
 901:           {
 902:         StringBuffer basepath = new StringBuffer(this.path);
 903:         int i = this.path.lastIndexOf('/');
 904: 
 905:         if (i >= 0)
 906:           basepath.delete(i + 1, basepath.length());
 907: 
 908:         basepath.append(path);
 909:         path = normalizePath(basepath.toString());
 910:           }
 911:       }
 912:     return new URI(this.scheme, authority, path, query, fragment);
 913:       }
 914:     catch (URISyntaxException e)
 915:       {
 916:     throw (Error) new InternalError("Resolved URI variant could not "+
 917:                     "be constructed").initCause(e);
 918:       }
 919:   }
 920: 
 921:   /**
 922:    * Resolves the given URI string against this URI
 923:    *
 924:    * @param str The URI as string to resolve against this URI
 925:    *
 926:    * @return The resulting URI
 927:    *
 928:    * @throws IllegalArgumentException If the given URI string
 929:    * violates RFC 2396
 930:    * @throws NullPointerException If uri is null
 931:    */
 932:   public URI resolve(String str) throws IllegalArgumentException
 933:   {
 934:     return resolve(create(str));
 935:   }
 936: 
 937:   /**
 938:    * <p>
 939:    * Relativizes the given URI against this URI.  The following
 940:    * algorithm is used:
 941:    * </p>
 942:    * <ul>
 943:    * <li>If either URI is opaque, the given URI is returned.</li>
 944:    * <li>If the schemes of the URIs differ, the given URI is returned.</li>
 945:    * <li>If the authority components of the URIs differ, then the given
 946:    * URI is returned.</li>
 947:    * <li>If the path of this URI is not a prefix of the supplied URI,
 948:    * then the given URI is returned.</li>
 949:    * <li>If all the above conditions hold, a new URI is created using the
 950:    * query and fragment components of the given URI, along with a path
 951:    * computed by removing the path of this URI from the start of the path
 952:    * of the supplied URI.</li>
 953:    * </ul>
 954:    *
 955:    * @param uri the URI to relativize agsint this URI
 956:    * @return the resulting URI
 957:    * @throws NullPointerException if the uri is null
 958:    */
 959:   public URI relativize(URI uri)
 960:   {
 961:     if (isOpaque() || uri.isOpaque())
 962:       return uri;
 963:     if (scheme == null && uri.getScheme() != null)
 964:       return uri;
 965:     if (scheme != null && !(scheme.equals(uri.getScheme())))
 966:       return uri;
 967:     if (rawAuthority == null && uri.getRawAuthority() != null)
 968:       return uri;
 969:     if (rawAuthority != null && !(rawAuthority.equals(uri.getRawAuthority())))
 970:       return uri;
 971:     if (!(uri.getRawPath().startsWith(rawPath)))
 972:       return uri;
 973:     try
 974:       {
 975:     return new URI(null, null, 
 976:                uri.getRawPath().substring(rawPath.length()),
 977:                uri.getRawQuery(), uri.getRawFragment());
 978:       }
 979:     catch (URISyntaxException e)
 980:       {
 981:     throw (Error) new InternalError("Relativized URI variant could not "+
 982:                     "be constructed").initCause(e);       
 983:       }
 984:   }
 985: 
 986:   /**
 987:    * Creates an URL from an URI
 988:    *
 989:    * @throws MalformedURLException If a protocol handler for the URL could
 990:    * not be found, or if some other error occurred while constructing the URL
 991:    * @throws IllegalArgumentException If the URI is not absolute
 992:    */
 993:   public URL toURL() throws IllegalArgumentException, MalformedURLException
 994:   {
 995:     if (isAbsolute())
 996:       return new URL(this.toString());
 997: 
 998:     throw new IllegalArgumentException("not absolute");
 999:   }
1000: 
1001:   /**
1002:    * Returns the scheme of the URI
1003:    */
1004:   public String getScheme()
1005:   {
1006:     return scheme;
1007:   }
1008: 
1009:   /**
1010:    * Tells whether this URI is absolute or not
1011:    */
1012:   public boolean isAbsolute()
1013:   {
1014:     return scheme != null;
1015:   }
1016: 
1017:   /**
1018:    * Tell whether this URI is opaque or not
1019:    */
1020:   public boolean isOpaque()
1021:   {
1022:     return ((scheme != null) && ! (schemeSpecificPart.startsWith("/")));
1023:   }
1024: 
1025:   /**
1026:    * Returns the raw scheme specific part of this URI.
1027:    * The scheme-specific part is never undefined, though it may be empty
1028:    */
1029:   public String getRawSchemeSpecificPart()
1030:   {
1031:     return rawSchemeSpecificPart;
1032:   }
1033: 
1034:   /**
1035:    * Returns the decoded scheme specific part of this URI.
1036:    */
1037:   public String getSchemeSpecificPart()
1038:   {
1039:     return schemeSpecificPart;
1040:   }
1041: 
1042:   /**
1043:    * Returns the raw authority part of this URI
1044:    */
1045:   public String getRawAuthority()
1046:   {
1047:     return rawAuthority;
1048:   }
1049: 
1050:   /**
1051:    * Returns the decoded authority part of this URI
1052:    */
1053:   public String getAuthority()
1054:   {
1055:     return authority;
1056:   }
1057: 
1058:   /**
1059:    * Returns the raw user info part of this URI
1060:    */
1061:   public String getRawUserInfo()
1062:   {
1063:     return rawUserInfo;
1064:   }
1065: 
1066:   /**
1067:    * Returns the decoded user info part of this URI
1068:    */
1069:   public String getUserInfo()
1070:   {
1071:     return userInfo;
1072:   }
1073: 
1074:   /**
1075:    * Returns the hostname of the URI
1076:    */
1077:   public String getHost()
1078:   {
1079:     return host;
1080:   }
1081: 
1082:   /**
1083:    * Returns the port number of the URI
1084:    */
1085:   public int getPort()
1086:   {
1087:     return port;
1088:   }
1089: 
1090:   /**
1091:    * Returns the raw path part of this URI
1092:    */
1093:   public String getRawPath()
1094:   {
1095:     return rawPath;
1096:   }
1097: 
1098:   /**
1099:    * Returns the path of the URI
1100:    */
1101:   public String getPath()
1102:   {
1103:     return path;
1104:   }
1105: 
1106:   /**
1107:    * Returns the raw query part of this URI
1108:    */
1109:   public String getRawQuery()
1110:   {
1111:     return rawQuery;
1112:   }
1113: 
1114:   /**
1115:    * Returns the query of the URI
1116:    */
1117:   public String getQuery()
1118:   {
1119:     return query;
1120:   }
1121: 
1122:   /**
1123:    * Return the raw fragment part of this URI
1124:    */
1125:   public String getRawFragment()
1126:   {
1127:     return rawFragment;
1128:   }
1129: 
1130:   /**
1131:    * Returns the fragment of the URI
1132:    */
1133:   public String getFragment()
1134:   {
1135:     return fragment;
1136:   }
1137: 
1138:   /**
1139:    * <p> 
1140:    * Compares the URI with the given object for equality.  If the
1141:    * object is not a <code>URI</code>, then the method returns false.
1142:    * Otherwise, the following criteria are observed:
1143:    * </p>
1144:    * <ul>
1145:    * <li>The scheme of the URIs must either be null (undefined) in both cases,
1146:    * or equal, ignorant of case.</li>
1147:    * <li>The raw fragment of the URIs must either be null (undefined) in both
1148:    * cases, or equal, ignorant of case.</li>
1149:    * <li>Both URIs must be of the same type (opaque or hierarchial)</li>
1150:    * <li><strong>For opaque URIs:</strong></li>
1151:    * <ul>
1152:    * <li>The raw scheme-specific parts must be equal.</li>
1153:    * </ul>
1154:    * <li>For hierarchical URIs:</li>
1155:    * <ul>
1156:    * <li>The raw paths must be equal, ignorant of case.</li>
1157:    * <li>The raw queries are either both undefined or both equal, ignorant
1158:    * of case.</li>
1159:    * <li>The raw authority sections are either both undefined or:</li>
1160:    * <li><strong>For registry-based authorities:</strong></li>
1161:    * <ul><li>they are equal.</li></ul>
1162:    * <li><strong>For server-based authorities:</strong></li>
1163:    * <ul>
1164:    * <li>the hosts are equal, ignoring case</li>
1165:    * <li>the ports are equal</li>
1166:    * <li>the user information components are equal</li>
1167:    * </ul>
1168:    * </ul>
1169:    * </ul>
1170:    *
1171:    * @param obj the obj to compare the URI with.
1172:    * @return <code>true</code> if the objects are equal, according to
1173:    *         the specification above.
1174:    */
1175:   public boolean equals(Object obj)
1176:   {
1177:     if (!(obj instanceof URI))
1178:       return false;
1179:     URI uriObj = (URI) obj;
1180:     if (scheme == null)
1181:       {
1182:     if (uriObj.getScheme() != null)
1183:       return false;
1184:       }
1185:     else
1186:       if (!(scheme.equalsIgnoreCase(uriObj.getScheme())))
1187:     return false;
1188:     if (rawFragment == null)
1189:       {
1190:     if (uriObj.getRawFragment() != null)
1191:       return false;
1192:       }
1193:     else
1194:       if (!(rawFragment.equalsIgnoreCase(uriObj.getRawFragment())))
1195:     return false;
1196:     boolean opaqueThis = isOpaque();
1197:     boolean opaqueObj = uriObj.isOpaque();
1198:     if (opaqueThis && opaqueObj)
1199:       return rawSchemeSpecificPart.equals(uriObj.getRawSchemeSpecificPart());
1200:     else if (!opaqueThis && !opaqueObj)
1201:       {
1202:     boolean common = rawPath.equalsIgnoreCase(uriObj.getRawPath())
1203:       && ((rawQuery == null && uriObj.getRawQuery() == null)
1204:           || rawQuery.equalsIgnoreCase(uriObj.getRawQuery()));
1205:     if (rawAuthority == null && uriObj.getRawAuthority() == null)
1206:       return common;
1207:     if (host == null)
1208:       return common 
1209:         && rawAuthority.equalsIgnoreCase(uriObj.getRawAuthority());
1210:     return common 
1211:       && host.equalsIgnoreCase(uriObj.getHost())
1212:       && port == uriObj.getPort()
1213:       && (rawUserInfo == null ?
1214:           uriObj.getRawUserInfo() == null :
1215:           rawUserInfo.equalsIgnoreCase(uriObj.getRawUserInfo()));
1216:       }
1217:     else
1218:       return false;
1219:   }
1220: 
1221:   /**
1222:    * Computes the hashcode of the URI
1223:    */
1224:   public int hashCode()
1225:   {
1226:     return (getScheme() == null ? 0 : 13 * getScheme().hashCode())
1227:       + 17 * getRawSchemeSpecificPart().hashCode()
1228:       + (getRawFragment() == null ? 0 : 21 + getRawFragment().hashCode());
1229:   }
1230: 
1231:   /**
1232:    * Compare the URI with another URI.
1233:    * Undefined components are taken to be less than any other component.
1234:    * The following criteria are observed:
1235:    * </p>
1236:    * <ul>
1237:    * <li>Two URIs with different schemes are compared according to their
1238:    * scheme, regardless of case.</li>
1239:    * <li>A hierarchical URI is less than an opaque URI with the same
1240:    * scheme.</li>
1241:    * <li><strong>For opaque URIs:</strong></li>
1242:    * <ul>
1243:    * <li>URIs with differing scheme-specific parts are ordered according
1244:    * to the ordering of the scheme-specific part.</li>
1245:    * <li>URIs with the same scheme-specific part are ordered by the
1246:    * raw fragment.</li>
1247:    * </ul>
1248:    * <li>For hierarchical URIs:</li>
1249:    * <ul>
1250:    * <li>URIs are ordered according to their raw authority sections,
1251:    * if they are unequal.</li>
1252:    * <li><strong>For registry-based authorities:</strong></li>
1253:    * <ul><li>they are ordered according to the ordering of the authority
1254:    * component.</li></ul>
1255:    * <li><strong>For server-based authorities:</strong></li>
1256:    * <ul>
1257:    * <li>URIs are ordered according to the raw user information.</li>
1258:    * <li>URIs with the same user information are ordered by the host,
1259:    * ignoring case.</li>
1260:    * <lI>URIs with the same host are ordered by the port.</li>
1261:    * </ul>
1262:    * <li>URIs with the same authority section are ordered by the raw path.</li>
1263:    * <li>URIs with the same path are ordered by their raw query.</li>
1264:    * <li>URIs with the same query are ordered by their raw fragments.</li>
1265:    * </ul>
1266:    * </ul>
1267:    *
1268:    * @param uri The other URI to compare this URI with
1269:    * @return a negative integer, zero or a positive integer depending
1270:    *         on whether this URI is less than, equal to or greater
1271:    *         than that supplied, respectively.
1272:    */
1273:   public int compareTo(URI uri) 
1274:     throws ClassCastException
1275:   {
1276:     if (scheme == null && uri.getScheme() != null)
1277:       return -1;
1278:     if (scheme != null)
1279:       {
1280:     int sCompare = scheme.compareToIgnoreCase(uri.getScheme()); 
1281:     if (sCompare != 0)
1282:       return sCompare;
1283:       }
1284:     boolean opaqueThis = isOpaque();
1285:     boolean opaqueObj = uri.isOpaque();
1286:     if (opaqueThis && !opaqueObj)
1287:       return 1;
1288:     if (!opaqueThis && opaqueObj)
1289:       return -1;
1290:     if (opaqueThis)
1291:       {
1292:     int ssCompare = 
1293:       rawSchemeSpecificPart.compareTo(uri.getRawSchemeSpecificPart());
1294:     if (ssCompare == 0)
1295:       return compareFragments(uri);
1296:     else
1297:       return ssCompare;
1298:       }
1299:     if (rawAuthority == null && uri.getRawAuthority() != null)
1300:       return -1;
1301:     if (rawAuthority != null)
1302:       {
1303:     int aCompare = rawAuthority.compareTo(uri.getRawAuthority());
1304:     if (aCompare != 0)
1305:       {
1306:         if (host == null)
1307:           return aCompare;
1308:         if (rawUserInfo == null && uri.getRawUserInfo() != null)
1309:           return -1;
1310:         int uCompare = rawUserInfo.compareTo(uri.getRawUserInfo());
1311:         if (uCompare != 0)
1312:           return uCompare;
1313:         if (host == null && uri.getHost() != null)
1314:           return -1;
1315:         int hCompare = host.compareTo(uri.getHost());
1316:         if (hCompare != 0)
1317:           return hCompare;
1318:         return new Integer(port).compareTo(new Integer(uri.getPort()));
1319:       }
1320:       }
1321:     if (rawPath == null && uri.getRawPath() != null)
1322:       return -1;
1323:     if (rawPath != null)
1324:       {
1325:     int pCompare = rawPath.compareTo(uri.getRawPath()); 
1326:     if (pCompare != 0)
1327:       return pCompare;
1328:       }
1329:     if (rawQuery == null && uri.getRawQuery() != null)
1330:       return -1;
1331:     if (rawQuery != null)
1332:       {
1333:     int qCompare = rawQuery.compareTo(uri.getRawQuery());
1334:     if (qCompare != 0)
1335:       return qCompare;
1336:       }
1337:     return compareFragments(uri);
1338:   }
1339: 
1340:   /**
1341:    * Compares the fragment of this URI with that of the supplied URI.
1342:    *
1343:    * @param uri the URI to compare with this one.
1344:    * @return a negative integer, zero or a positive integer depending
1345:    *         on whether this uri's fragment is less than, equal to
1346:    *         or greater than the fragment of the uri supplied, respectively.
1347:    */
1348:   private int compareFragments(URI uri)
1349:   {
1350:     if (rawFragment == null && uri.getRawFragment() != null)
1351:       return -1;
1352:     else if (rawFragment == null)
1353:       return 0;
1354:     else
1355:       return rawFragment.compareTo(uri.getRawFragment());
1356:   }
1357: 
1358:   /**
1359:    * Returns the URI as a String.  If the URI was created using a constructor,
1360:    * then this will be the same as the original input string.
1361:    *
1362:    * @return a string representation of the URI.
1363:    */
1364:   public String toString()
1365:   {
1366:     return (scheme == null ? "" : scheme + ":")
1367:       + rawSchemeSpecificPart
1368:       + (rawFragment == null ? "" : "#" + rawFragment);
1369:   }
1370: 
1371:   /**
1372:    * Returns the URI as US-ASCII string.  This is the same as the result
1373:    * from <code>toString()</code> for URIs that don't contain any non-US-ASCII
1374:    * characters.  Otherwise, the non-US-ASCII characters are replaced
1375:    * by their percent-encoded representations.
1376:    *
1377:    * @return a string representation of the URI, containing only US-ASCII
1378:    *         characters.
1379:    */
1380:   public String toASCIIString()
1381:   {
1382:     String strRep = toString();
1383:     boolean inNonAsciiBlock = false;
1384:     StringBuffer buffer = new StringBuffer();
1385:     StringBuffer encBuffer = null;
1386:     for (int i = 0; i < strRep.length(); i++)
1387:       {
1388:     char c = strRep.charAt(i);
1389:     if (c <= 127)
1390:       {
1391:         if (inNonAsciiBlock)
1392:           {
1393:         buffer.append(escapeCharacters(encBuffer.toString()));
1394:         inNonAsciiBlock = false;
1395:           }
1396:         buffer.append(c);
1397:       }
1398:     else
1399:       {
1400:         if (!inNonAsciiBlock)
1401:           {
1402:         encBuffer = new StringBuffer();
1403:         inNonAsciiBlock = true;
1404:           }
1405:         encBuffer.append(c);
1406:       }
1407:       }
1408:     return buffer.toString();
1409:   }
1410: 
1411:   /**
1412:    * Converts the non-ASCII characters in the supplied string
1413:    * to their equivalent percent-encoded representations.
1414:    * That is, they are replaced by "%" followed by their hexadecimal value.
1415:    *
1416:    * @param str a string including non-ASCII characters.
1417:    * @return the string with the non-ASCII characters converted to their
1418:    *         percent-encoded representations.
1419:    */
1420:   private static String escapeCharacters(String str)
1421:   {
1422:     try
1423:       {
1424:     StringBuffer sb = new StringBuffer(); 
1425:     // this is far from optimal, but it works
1426:     byte[] utf8 = str.getBytes("utf-8");
1427:     for (int j = 0; j < utf8.length; j++)
1428:       {
1429:         sb.append('%');
1430:         sb.append(HEX.charAt((utf8[j] & 0xff) / 16));
1431:         sb.append(HEX.charAt((utf8[j] & 0xff) % 16));
1432:       }
1433:     return sb.toString();
1434:       }
1435:     catch (java.io.UnsupportedEncodingException x)
1436:       {
1437:     throw (Error) new InternalError("Escaping error").initCause(x);
1438:       }
1439:   }
1440: 
1441: }