Shuyi Chen | d7955ce | 2013-05-22 14:51:55 -0700 | [diff] [blame] | 1 | // Copyright (c) 2002-2004 Brian Wellington (bwelling@xbill.org) |
| 2 | |
| 3 | package org.xbill.DNS; |
| 4 | |
| 5 | import java.util.*; |
| 6 | import java.io.*; |
| 7 | import java.net.*; |
| 8 | |
| 9 | /** |
| 10 | * The Lookup object issues queries to caching DNS servers. The input consists |
| 11 | * of a name, an optional type, and an optional class. Caching is enabled |
| 12 | * by default and used when possible to reduce the number of DNS requests. |
| 13 | * A Resolver, which defaults to an ExtendedResolver initialized with the |
| 14 | * resolvers located by the ResolverConfig class, performs the queries. A |
| 15 | * search path of domain suffixes is used to resolve relative names, and is |
| 16 | * also determined by the ResolverConfig class. |
| 17 | * |
| 18 | * A Lookup object may be reused, but should not be used by multiple threads. |
| 19 | * |
| 20 | * @see Cache |
| 21 | * @see Resolver |
| 22 | * @see ResolverConfig |
| 23 | * |
| 24 | * @author Brian Wellington |
| 25 | */ |
| 26 | |
| 27 | public final class Lookup { |
| 28 | |
| 29 | private static Resolver defaultResolver; |
| 30 | private static Name [] defaultSearchPath; |
| 31 | private static Map defaultCaches; |
| 32 | private static int defaultNdots; |
| 33 | |
| 34 | private Resolver resolver; |
| 35 | private Name [] searchPath; |
| 36 | private Cache cache; |
| 37 | private boolean temporary_cache; |
| 38 | private int credibility; |
| 39 | private Name name; |
| 40 | private int type; |
| 41 | private int dclass; |
| 42 | private boolean verbose; |
| 43 | private int iterations; |
| 44 | private boolean foundAlias; |
| 45 | private boolean done; |
| 46 | private boolean doneCurrent; |
| 47 | private List aliases; |
| 48 | private Record [] answers; |
| 49 | private int result; |
| 50 | private String error; |
| 51 | private boolean nxdomain; |
| 52 | private boolean badresponse; |
| 53 | private String badresponse_error; |
| 54 | private boolean networkerror; |
| 55 | private boolean timedout; |
| 56 | private boolean nametoolong; |
| 57 | private boolean referral; |
| 58 | |
| 59 | private static final Name [] noAliases = new Name[0]; |
| 60 | |
| 61 | /** The lookup was successful. */ |
| 62 | public static final int SUCCESSFUL = 0; |
| 63 | |
| 64 | /** |
| 65 | * The lookup failed due to a data or server error. Repeating the lookup |
| 66 | * would not be helpful. |
| 67 | */ |
| 68 | public static final int UNRECOVERABLE = 1; |
| 69 | |
| 70 | /** |
| 71 | * The lookup failed due to a network error. Repeating the lookup may be |
| 72 | * helpful. |
| 73 | */ |
| 74 | public static final int TRY_AGAIN = 2; |
| 75 | |
| 76 | /** The host does not exist. */ |
| 77 | public static final int HOST_NOT_FOUND = 3; |
| 78 | |
| 79 | /** The host exists, but has no records associated with the queried type. */ |
| 80 | public static final int TYPE_NOT_FOUND = 4; |
| 81 | |
| 82 | public static synchronized void |
| 83 | refreshDefault() { |
| 84 | |
| 85 | try { |
| 86 | defaultResolver = new ExtendedResolver(); |
| 87 | } |
| 88 | catch (UnknownHostException e) { |
| 89 | throw new RuntimeException("Failed to initialize resolver"); |
| 90 | } |
| 91 | defaultSearchPath = ResolverConfig.getCurrentConfig().searchPath(); |
| 92 | defaultCaches = new HashMap(); |
| 93 | defaultNdots = ResolverConfig.getCurrentConfig().ndots(); |
| 94 | } |
| 95 | |
| 96 | static { |
| 97 | refreshDefault(); |
| 98 | } |
| 99 | |
| 100 | /** |
| 101 | * Gets the Resolver that will be used as the default by future Lookups. |
| 102 | * @return The default resolver. |
| 103 | */ |
| 104 | public static synchronized Resolver |
| 105 | getDefaultResolver() { |
| 106 | return defaultResolver; |
| 107 | } |
| 108 | |
| 109 | /** |
| 110 | * Sets the default Resolver to be used as the default by future Lookups. |
| 111 | * @param resolver The default resolver. |
| 112 | */ |
| 113 | public static synchronized void |
| 114 | setDefaultResolver(Resolver resolver) { |
| 115 | defaultResolver = resolver; |
| 116 | } |
| 117 | |
| 118 | /** |
| 119 | * Gets the Cache that will be used as the default for the specified |
| 120 | * class by future Lookups. |
| 121 | * @param dclass The class whose cache is being retrieved. |
| 122 | * @return The default cache for the specified class. |
| 123 | */ |
| 124 | public static synchronized Cache |
| 125 | getDefaultCache(int dclass) { |
| 126 | DClass.check(dclass); |
| 127 | Cache c = (Cache) defaultCaches.get(Mnemonic.toInteger(dclass)); |
| 128 | if (c == null) { |
| 129 | c = new Cache(dclass); |
| 130 | defaultCaches.put(Mnemonic.toInteger(dclass), c); |
| 131 | } |
| 132 | return c; |
| 133 | } |
| 134 | |
| 135 | /** |
| 136 | * Sets the Cache to be used as the default for the specified class by future |
| 137 | * Lookups. |
| 138 | * @param cache The default cache for the specified class. |
| 139 | * @param dclass The class whose cache is being set. |
| 140 | */ |
| 141 | public static synchronized void |
| 142 | setDefaultCache(Cache cache, int dclass) { |
| 143 | DClass.check(dclass); |
| 144 | defaultCaches.put(Mnemonic.toInteger(dclass), cache); |
| 145 | } |
| 146 | |
| 147 | /** |
| 148 | * Gets the search path that will be used as the default by future Lookups. |
| 149 | * @return The default search path. |
| 150 | */ |
| 151 | public static synchronized Name [] |
| 152 | getDefaultSearchPath() { |
| 153 | return defaultSearchPath; |
| 154 | } |
| 155 | |
| 156 | /** |
| 157 | * Sets the search path to be used as the default by future Lookups. |
| 158 | * @param domains The default search path. |
| 159 | */ |
| 160 | public static synchronized void |
| 161 | setDefaultSearchPath(Name [] domains) { |
| 162 | defaultSearchPath = domains; |
| 163 | } |
| 164 | |
| 165 | /** |
| 166 | * Sets the search path that will be used as the default by future Lookups. |
| 167 | * @param domains The default search path. |
| 168 | * @throws TextParseException A name in the array is not a valid DNS name. |
| 169 | */ |
| 170 | public static synchronized void |
| 171 | setDefaultSearchPath(String [] domains) throws TextParseException { |
| 172 | if (domains == null) { |
| 173 | defaultSearchPath = null; |
| 174 | return; |
| 175 | } |
| 176 | Name [] newdomains = new Name[domains.length]; |
| 177 | for (int i = 0; i < domains.length; i++) |
| 178 | newdomains[i] = Name.fromString(domains[i], Name.root); |
| 179 | defaultSearchPath = newdomains; |
| 180 | } |
| 181 | |
| 182 | private final void |
| 183 | reset() { |
| 184 | iterations = 0; |
| 185 | foundAlias = false; |
| 186 | done = false; |
| 187 | doneCurrent = false; |
| 188 | aliases = null; |
| 189 | answers = null; |
| 190 | result = -1; |
| 191 | error = null; |
| 192 | nxdomain = false; |
| 193 | badresponse = false; |
| 194 | badresponse_error = null; |
| 195 | networkerror = false; |
| 196 | timedout = false; |
| 197 | nametoolong = false; |
| 198 | referral = false; |
| 199 | if (temporary_cache) |
| 200 | cache.clearCache(); |
| 201 | } |
| 202 | |
| 203 | /** |
| 204 | * Create a Lookup object that will find records of the given name, type, |
| 205 | * and class. The lookup will use the default cache, resolver, and search |
| 206 | * path, and look for records that are reasonably credible. |
| 207 | * @param name The name of the desired records |
| 208 | * @param type The type of the desired records |
| 209 | * @param dclass The class of the desired records |
| 210 | * @throws IllegalArgumentException The type is a meta type other than ANY. |
| 211 | * @see Cache |
| 212 | * @see Resolver |
| 213 | * @see Credibility |
| 214 | * @see Name |
| 215 | * @see Type |
| 216 | * @see DClass |
| 217 | */ |
| 218 | public |
| 219 | Lookup(Name name, int type, int dclass) { |
| 220 | Type.check(type); |
| 221 | DClass.check(dclass); |
| 222 | if (!Type.isRR(type) && type != Type.ANY) |
| 223 | throw new IllegalArgumentException("Cannot query for " + |
| 224 | "meta-types other than ANY"); |
| 225 | this.name = name; |
| 226 | this.type = type; |
| 227 | this.dclass = dclass; |
| 228 | synchronized (Lookup.class) { |
| 229 | this.resolver = getDefaultResolver(); |
| 230 | this.searchPath = getDefaultSearchPath(); |
| 231 | this.cache = getDefaultCache(dclass); |
| 232 | } |
| 233 | this.credibility = Credibility.NORMAL; |
| 234 | this.verbose = Options.check("verbose"); |
| 235 | this.result = -1; |
| 236 | } |
| 237 | |
| 238 | /** |
| 239 | * Create a Lookup object that will find records of the given name and type |
| 240 | * in the IN class. |
| 241 | * @param name The name of the desired records |
| 242 | * @param type The type of the desired records |
| 243 | * @throws IllegalArgumentException The type is a meta type other than ANY. |
| 244 | * @see #Lookup(Name,int,int) |
| 245 | */ |
| 246 | public |
| 247 | Lookup(Name name, int type) { |
| 248 | this(name, type, DClass.IN); |
| 249 | } |
| 250 | |
| 251 | /** |
| 252 | * Create a Lookup object that will find records of type A at the given name |
| 253 | * in the IN class. |
| 254 | * @param name The name of the desired records |
| 255 | * @see #Lookup(Name,int,int) |
| 256 | */ |
| 257 | public |
| 258 | Lookup(Name name) { |
| 259 | this(name, Type.A, DClass.IN); |
| 260 | } |
| 261 | |
| 262 | /** |
| 263 | * Create a Lookup object that will find records of the given name, type, |
| 264 | * and class. |
| 265 | * @param name The name of the desired records |
| 266 | * @param type The type of the desired records |
| 267 | * @param dclass The class of the desired records |
| 268 | * @throws TextParseException The name is not a valid DNS name |
| 269 | * @throws IllegalArgumentException The type is a meta type other than ANY. |
| 270 | * @see #Lookup(Name,int,int) |
| 271 | */ |
| 272 | public |
| 273 | Lookup(String name, int type, int dclass) throws TextParseException { |
| 274 | this(Name.fromString(name), type, dclass); |
| 275 | } |
| 276 | |
| 277 | /** |
| 278 | * Create a Lookup object that will find records of the given name and type |
| 279 | * in the IN class. |
| 280 | * @param name The name of the desired records |
| 281 | * @param type The type of the desired records |
| 282 | * @throws TextParseException The name is not a valid DNS name |
| 283 | * @throws IllegalArgumentException The type is a meta type other than ANY. |
| 284 | * @see #Lookup(Name,int,int) |
| 285 | */ |
| 286 | public |
| 287 | Lookup(String name, int type) throws TextParseException { |
| 288 | this(Name.fromString(name), type, DClass.IN); |
| 289 | } |
| 290 | |
| 291 | /** |
| 292 | * Create a Lookup object that will find records of type A at the given name |
| 293 | * in the IN class. |
| 294 | * @param name The name of the desired records |
| 295 | * @throws TextParseException The name is not a valid DNS name |
| 296 | * @see #Lookup(Name,int,int) |
| 297 | */ |
| 298 | public |
| 299 | Lookup(String name) throws TextParseException { |
| 300 | this(Name.fromString(name), Type.A, DClass.IN); |
| 301 | } |
| 302 | |
| 303 | /** |
| 304 | * Sets the resolver to use when performing this lookup. This overrides the |
| 305 | * default value. |
| 306 | * @param resolver The resolver to use. |
| 307 | */ |
| 308 | public void |
| 309 | setResolver(Resolver resolver) { |
| 310 | this.resolver = resolver; |
| 311 | } |
| 312 | |
| 313 | /** |
| 314 | * Sets the search path to use when performing this lookup. This overrides the |
| 315 | * default value. |
| 316 | * @param domains An array of names containing the search path. |
| 317 | */ |
| 318 | public void |
| 319 | setSearchPath(Name [] domains) { |
| 320 | this.searchPath = domains; |
| 321 | } |
| 322 | |
| 323 | /** |
| 324 | * Sets the search path to use when performing this lookup. This overrides the |
| 325 | * default value. |
| 326 | * @param domains An array of names containing the search path. |
| 327 | * @throws TextParseException A name in the array is not a valid DNS name. |
| 328 | */ |
| 329 | public void |
| 330 | setSearchPath(String [] domains) throws TextParseException { |
| 331 | if (domains == null) { |
| 332 | this.searchPath = null; |
| 333 | return; |
| 334 | } |
| 335 | Name [] newdomains = new Name[domains.length]; |
| 336 | for (int i = 0; i < domains.length; i++) |
| 337 | newdomains[i] = Name.fromString(domains[i], Name.root); |
| 338 | this.searchPath = newdomains; |
| 339 | } |
| 340 | |
| 341 | /** |
| 342 | * Sets the cache to use when performing this lookup. This overrides the |
| 343 | * default value. If the results of this lookup should not be permanently |
| 344 | * cached, null can be provided here. |
| 345 | * @param cache The cache to use. |
| 346 | */ |
| 347 | public void |
| 348 | setCache(Cache cache) { |
| 349 | if (cache == null) { |
| 350 | this.cache = new Cache(dclass); |
| 351 | this.temporary_cache = true; |
| 352 | } else { |
| 353 | this.cache = cache; |
| 354 | this.temporary_cache = false; |
| 355 | } |
| 356 | } |
| 357 | |
| 358 | /** |
| 359 | * Sets ndots to use when performing this lookup, overriding the default value. |
| 360 | * Specifically, this refers to the number of "dots" which, if present in a |
| 361 | * name, indicate that a lookup for the absolute name should be attempted |
| 362 | * before appending any search path elements. |
| 363 | * @param ndots The ndots value to use, which must be greater than or equal to |
| 364 | * 0. |
| 365 | */ |
| 366 | public void |
| 367 | setNdots(int ndots) { |
| 368 | if (ndots < 0) |
| 369 | throw new IllegalArgumentException("Illegal ndots value: " + |
| 370 | ndots); |
| 371 | defaultNdots = ndots; |
| 372 | } |
| 373 | |
| 374 | /** |
| 375 | * Sets the minimum credibility level that will be accepted when performing |
| 376 | * the lookup. This defaults to Credibility.NORMAL. |
| 377 | * @param credibility The minimum credibility level. |
| 378 | */ |
| 379 | public void |
| 380 | setCredibility(int credibility) { |
| 381 | this.credibility = credibility; |
| 382 | } |
| 383 | |
| 384 | private void |
| 385 | follow(Name name, Name oldname) { |
| 386 | foundAlias = true; |
| 387 | badresponse = false; |
| 388 | networkerror = false; |
| 389 | timedout = false; |
| 390 | nxdomain = false; |
| 391 | referral = false; |
| 392 | iterations++; |
| 393 | if (iterations >= 6 || name.equals(oldname)) { |
| 394 | result = UNRECOVERABLE; |
| 395 | error = "CNAME loop"; |
| 396 | done = true; |
| 397 | return; |
| 398 | } |
| 399 | if (aliases == null) |
| 400 | aliases = new ArrayList(); |
| 401 | aliases.add(oldname); |
| 402 | lookup(name); |
| 403 | } |
| 404 | |
| 405 | private void |
| 406 | processResponse(Name name, SetResponse response) { |
| 407 | if (response.isSuccessful()) { |
| 408 | RRset [] rrsets = response.answers(); |
| 409 | List l = new ArrayList(); |
| 410 | Iterator it; |
| 411 | int i; |
| 412 | |
| 413 | for (i = 0; i < rrsets.length; i++) { |
| 414 | it = rrsets[i].rrs(); |
| 415 | while (it.hasNext()) |
| 416 | l.add(it.next()); |
| 417 | } |
| 418 | |
| 419 | result = SUCCESSFUL; |
| 420 | answers = (Record []) l.toArray(new Record[l.size()]); |
| 421 | done = true; |
| 422 | } else if (response.isNXDOMAIN()) { |
| 423 | nxdomain = true; |
| 424 | doneCurrent = true; |
| 425 | if (iterations > 0) { |
| 426 | result = HOST_NOT_FOUND; |
| 427 | done = true; |
| 428 | } |
| 429 | } else if (response.isNXRRSET()) { |
| 430 | result = TYPE_NOT_FOUND; |
| 431 | answers = null; |
| 432 | done = true; |
| 433 | } else if (response.isCNAME()) { |
| 434 | CNAMERecord cname = response.getCNAME(); |
| 435 | follow(cname.getTarget(), name); |
| 436 | } else if (response.isDNAME()) { |
| 437 | DNAMERecord dname = response.getDNAME(); |
| 438 | try { |
| 439 | follow(name.fromDNAME(dname), name); |
| 440 | } catch (NameTooLongException e) { |
| 441 | result = UNRECOVERABLE; |
| 442 | error = "Invalid DNAME target"; |
| 443 | done = true; |
| 444 | } |
| 445 | } else if (response.isDelegation()) { |
| 446 | // We shouldn't get a referral. Ignore it. |
| 447 | referral = true; |
| 448 | } |
| 449 | } |
| 450 | |
| 451 | private void |
| 452 | lookup(Name current) { |
| 453 | SetResponse sr = cache.lookupRecords(current, type, credibility); |
| 454 | if (verbose) { |
| 455 | System.err.println("lookup " + current + " " + |
| 456 | Type.string(type)); |
| 457 | System.err.println(sr); |
| 458 | } |
| 459 | processResponse(current, sr); |
| 460 | if (done || doneCurrent) |
| 461 | return; |
| 462 | |
| 463 | Record question = Record.newRecord(current, type, dclass); |
| 464 | Message query = Message.newQuery(question); |
| 465 | Message response = null; |
| 466 | try { |
| 467 | response = resolver.send(query); |
| 468 | } |
| 469 | catch (IOException e) { |
| 470 | // A network error occurred. Press on. |
| 471 | if (e instanceof InterruptedIOException) |
| 472 | timedout = true; |
| 473 | else |
| 474 | networkerror = true; |
| 475 | return; |
| 476 | } |
| 477 | int rcode = response.getHeader().getRcode(); |
| 478 | if (rcode != Rcode.NOERROR && rcode != Rcode.NXDOMAIN) { |
| 479 | // The server we contacted is broken or otherwise unhelpful. |
| 480 | // Press on. |
| 481 | badresponse = true; |
| 482 | badresponse_error = Rcode.string(rcode); |
| 483 | return; |
| 484 | } |
| 485 | |
| 486 | if (!query.getQuestion().equals(response.getQuestion())) { |
| 487 | // The answer doesn't match the question. That's not good. |
| 488 | badresponse = true; |
| 489 | badresponse_error = "response does not match query"; |
| 490 | return; |
| 491 | } |
| 492 | |
| 493 | sr = cache.addMessage(response); |
| 494 | if (sr == null) |
| 495 | sr = cache.lookupRecords(current, type, credibility); |
| 496 | if (verbose) { |
| 497 | System.err.println("queried " + current + " " + |
| 498 | Type.string(type)); |
| 499 | System.err.println(sr); |
| 500 | } |
| 501 | processResponse(current, sr); |
| 502 | } |
| 503 | |
| 504 | private void |
| 505 | resolve(Name current, Name suffix) { |
| 506 | doneCurrent = false; |
| 507 | Name tname = null; |
| 508 | if (suffix == null) |
| 509 | tname = current; |
| 510 | else { |
| 511 | try { |
| 512 | tname = Name.concatenate(current, suffix); |
| 513 | } |
| 514 | catch (NameTooLongException e) { |
| 515 | nametoolong = true; |
| 516 | return; |
| 517 | } |
| 518 | } |
| 519 | lookup(tname); |
| 520 | } |
| 521 | |
| 522 | /** |
| 523 | * Performs the lookup, using the specified Cache, Resolver, and search path. |
| 524 | * @return The answers, or null if none are found. |
| 525 | */ |
| 526 | public Record [] |
| 527 | run() { |
| 528 | if (done) |
| 529 | reset(); |
| 530 | if (name.isAbsolute()) |
| 531 | resolve(name, null); |
| 532 | else if (searchPath == null) |
| 533 | resolve(name, Name.root); |
| 534 | else { |
| 535 | if (name.labels() > defaultNdots) |
| 536 | resolve(name, Name.root); |
| 537 | if (done) |
| 538 | return answers; |
| 539 | |
| 540 | for (int i = 0; i < searchPath.length; i++) { |
| 541 | resolve(name, searchPath[i]); |
| 542 | if (done) |
| 543 | return answers; |
| 544 | else if (foundAlias) |
| 545 | break; |
| 546 | } |
| 547 | } |
| 548 | if (!done) { |
| 549 | if (badresponse) { |
| 550 | result = TRY_AGAIN; |
| 551 | error = badresponse_error; |
| 552 | done = true; |
| 553 | } else if (timedout) { |
| 554 | result = TRY_AGAIN; |
| 555 | error = "timed out"; |
| 556 | done = true; |
| 557 | } else if (networkerror) { |
| 558 | result = TRY_AGAIN; |
| 559 | error = "network error"; |
| 560 | done = true; |
| 561 | } else if (nxdomain) { |
| 562 | result = HOST_NOT_FOUND; |
| 563 | done = true; |
| 564 | } else if (referral) { |
| 565 | result = UNRECOVERABLE; |
| 566 | error = "referral"; |
| 567 | done = true; |
| 568 | } else if (nametoolong) { |
| 569 | result = UNRECOVERABLE; |
| 570 | error = "name too long"; |
| 571 | done = true; |
| 572 | } |
| 573 | } |
| 574 | return answers; |
| 575 | } |
| 576 | |
| 577 | private void |
| 578 | checkDone() { |
| 579 | if (done && result != -1) |
| 580 | return; |
| 581 | StringBuffer sb = new StringBuffer("Lookup of " + name + " "); |
| 582 | if (dclass != DClass.IN) |
| 583 | sb.append(DClass.string(dclass) + " "); |
| 584 | sb.append(Type.string(type) + " isn't done"); |
| 585 | throw new IllegalStateException(sb.toString()); |
| 586 | } |
| 587 | |
| 588 | /** |
| 589 | * Returns the answers from the lookup. |
| 590 | * @return The answers, or null if none are found. |
| 591 | * @throws IllegalStateException The lookup has not completed. |
| 592 | */ |
| 593 | public Record [] |
| 594 | getAnswers() { |
| 595 | checkDone(); |
| 596 | return answers; |
| 597 | } |
| 598 | |
| 599 | /** |
| 600 | * Returns all known aliases for this name. Whenever a CNAME/DNAME is |
| 601 | * followed, an alias is added to this array. The last element in this |
| 602 | * array will be the owner name for records in the answer, if there are any. |
| 603 | * @return The aliases. |
| 604 | * @throws IllegalStateException The lookup has not completed. |
| 605 | */ |
| 606 | public Name [] |
| 607 | getAliases() { |
| 608 | checkDone(); |
| 609 | if (aliases == null) |
| 610 | return noAliases; |
| 611 | return (Name []) aliases.toArray(new Name[aliases.size()]); |
| 612 | } |
| 613 | |
| 614 | /** |
| 615 | * Returns the result code of the lookup. |
| 616 | * @return The result code, which can be SUCCESSFUL, UNRECOVERABLE, TRY_AGAIN, |
| 617 | * HOST_NOT_FOUND, or TYPE_NOT_FOUND. |
| 618 | * @throws IllegalStateException The lookup has not completed. |
| 619 | */ |
| 620 | public int |
| 621 | getResult() { |
| 622 | checkDone(); |
| 623 | return result; |
| 624 | } |
| 625 | |
| 626 | /** |
| 627 | * Returns an error string describing the result code of this lookup. |
| 628 | * @return A string, which may either directly correspond the result code |
| 629 | * or be more specific. |
| 630 | * @throws IllegalStateException The lookup has not completed. |
| 631 | */ |
| 632 | public String |
| 633 | getErrorString() { |
| 634 | checkDone(); |
| 635 | if (error != null) |
| 636 | return error; |
| 637 | switch (result) { |
| 638 | case SUCCESSFUL: return "successful"; |
| 639 | case UNRECOVERABLE: return "unrecoverable error"; |
| 640 | case TRY_AGAIN: return "try again"; |
| 641 | case HOST_NOT_FOUND: return "host not found"; |
| 642 | case TYPE_NOT_FOUND: return "type not found"; |
| 643 | } |
| 644 | throw new IllegalStateException("unknown result"); |
| 645 | } |
| 646 | |
| 647 | } |