1 /*
   2  * reserved comment block
   3  * DO NOT REMOVE OR ALTER!
   4  */
   5 /*
   6  * Copyright 1999-2005 The Apache Software Foundation.
   7  *
   8  * Licensed under the Apache License, Version 2.0 (the "License");
   9  * you may not use this file except in compliance with the License.
  10  * You may obtain a copy of the License at
  11  *
  12  *      http://www.apache.org/licenses/LICENSE-2.0
  13  *
  14  * Unless required by applicable law or agreed to in writing, software
  15  * distributed under the License is distributed on an "AS IS" BASIS,
  16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  17  * See the License for the specific language governing permissions and
  18  * limitations under the License.
  19  */
  20 
  21 package com.sun.org.apache.xerces.internal.util;
  22 
  23 import java.io.IOException;
  24 import java.io.Serializable;
  25 import java.util.Objects;
  26 
  27 /**********************************************************************
  28 * A class to represent a Uniform Resource Identifier (URI). This class
  29 * is designed to handle the parsing of URIs and provide access to
  30 * the various components (scheme, host, port, userinfo, path, query
  31 * string and fragment) that may constitute a URI.
  32 * <p>
  33 * Parsing of a URI specification is done according to the URI
  34 * syntax described in
  35 * <a href="http://www.ietf.org/rfc/rfc2396.txt?number=2396">RFC 2396</a>,
  36 * and amended by
  37 * <a href="http://www.ietf.org/rfc/rfc2732.txt?number=2732">RFC 2732</a>.
  38 * <p>
  39 * Every absolute URI consists of a scheme, followed by a colon (':'),
  40 * followed by a scheme-specific part. For URIs that follow the
  41 * "generic URI" syntax, the scheme-specific part begins with two
  42 * slashes ("//") and may be followed by an authority segment (comprised
  43 * of user information, host, and port), path segment, query segment
  44 * and fragment. Note that RFC 2396 no longer specifies the use of the
  45 * parameters segment and excludes the "user:password" syntax as part of
  46 * the authority segment. If "user:password" appears in a URI, the entire
  47 * user/password string is stored as userinfo.
  48 * <p>
  49 * For URIs that do not follow the "generic URI" syntax (e.g. mailto),
  50 * the entire scheme-specific part is treated as the "path" portion
  51 * of the URI.
  52 * <p>
  53 * Note that, unlike the java.net.URL class, this class does not provide
  54 * any built-in network access functionality nor does it provide any
  55 * scheme-specific functionality (for example, it does not know a
  56 * default port for a specific scheme). Rather, it only knows the
  57 * grammar and basic set of operations that can be applied to a URI.
  58 *
  59 *
  60 **********************************************************************/
  61  public class URI implements Serializable {
  62 
  63   /*******************************************************************
  64   * MalformedURIExceptions are thrown in the process of building a URI
  65   * or setting fields on a URI when an operation would result in an
  66   * invalid URI specification.
  67   *
  68   ********************************************************************/
  69   public static class MalformedURIException extends IOException {
  70 
  71    /** Serialization version. */
  72    static final long serialVersionUID = -6695054834342951930L;
  73 
  74    /******************************************************************
  75     * Constructs a <code>MalformedURIException</code> with no specified
  76     * detail message.
  77     ******************************************************************/
  78     public MalformedURIException() {
  79       super();
  80     }
  81 
  82     /*****************************************************************
  83     * Constructs a <code>MalformedURIException</code> with the
  84     * specified detail message.
  85     *
  86     * @param p_msg the detail message.
  87     ******************************************************************/
  88     public MalformedURIException(String p_msg) {
  89       super(p_msg);
  90     }
  91   }
  92 
  93   /** Serialization version. */
  94   static final long serialVersionUID = 1601921774685357214L;
  95 
  96   private static final byte [] fgLookupTable = new byte[128];
  97 
  98   /**
  99    * Character Classes
 100    */
 101 
 102   /** reserved characters ;/?:@&=+$,[] */
 103   //RFC 2732 added '[' and ']' as reserved characters
 104   private static final int RESERVED_CHARACTERS = 0x01;
 105 
 106   /** URI punctuation mark characters: -_.!~*'() - these, combined with
 107       alphanumerics, constitute the "unreserved" characters */
 108   private static final int MARK_CHARACTERS = 0x02;
 109 
 110   /** scheme can be composed of alphanumerics and these characters: +-. */
 111   private static final int SCHEME_CHARACTERS = 0x04;
 112 
 113   /** userinfo can be composed of unreserved, escaped and these
 114       characters: ;:&=+$, */
 115   private static final int USERINFO_CHARACTERS = 0x08;
 116 
 117   /** ASCII letter characters */
 118   private static final int ASCII_ALPHA_CHARACTERS = 0x10;
 119 
 120   /** ASCII digit characters */
 121   private static final int ASCII_DIGIT_CHARACTERS = 0x20;
 122 
 123   /** ASCII hex characters */
 124   private static final int ASCII_HEX_CHARACTERS = 0x40;
 125 
 126   /** Path characters */
 127   private static final int PATH_CHARACTERS = 0x80;
 128 
 129   /** Mask for alpha-numeric characters */
 130   private static final int MASK_ALPHA_NUMERIC = ASCII_ALPHA_CHARACTERS | ASCII_DIGIT_CHARACTERS;
 131 
 132   /** Mask for unreserved characters */
 133   private static final int MASK_UNRESERVED_MASK = MASK_ALPHA_NUMERIC | MARK_CHARACTERS;
 134 
 135   /** Mask for URI allowable characters except for % */
 136   private static final int MASK_URI_CHARACTER = MASK_UNRESERVED_MASK | RESERVED_CHARACTERS;
 137 
 138   /** Mask for scheme characters */
 139   private static final int MASK_SCHEME_CHARACTER = MASK_ALPHA_NUMERIC | SCHEME_CHARACTERS;
 140 
 141   /** Mask for userinfo characters */
 142   private static final int MASK_USERINFO_CHARACTER = MASK_UNRESERVED_MASK | USERINFO_CHARACTERS;
 143 
 144   /** Mask for path characters */
 145   private static final int MASK_PATH_CHARACTER = MASK_UNRESERVED_MASK | PATH_CHARACTERS;
 146 
 147   static {
 148       // Add ASCII Digits and ASCII Hex Numbers
 149       for (int i = '0'; i <= '9'; ++i) {
 150           fgLookupTable[i] |= ASCII_DIGIT_CHARACTERS | ASCII_HEX_CHARACTERS;
 151       }
 152 
 153       // Add ASCII Letters and ASCII Hex Numbers
 154       for (int i = 'A'; i <= 'F'; ++i) {
 155           fgLookupTable[i] |= ASCII_ALPHA_CHARACTERS | ASCII_HEX_CHARACTERS;
 156           fgLookupTable[i+0x00000020] |= ASCII_ALPHA_CHARACTERS | ASCII_HEX_CHARACTERS;
 157       }
 158 
 159       // Add ASCII Letters
 160       for (int i = 'G'; i <= 'Z'; ++i) {
 161           fgLookupTable[i] |= ASCII_ALPHA_CHARACTERS;
 162           fgLookupTable[i+0x00000020] |= ASCII_ALPHA_CHARACTERS;
 163       }
 164 
 165       // Add Reserved Characters
 166       fgLookupTable[';'] |= RESERVED_CHARACTERS;
 167       fgLookupTable['/'] |= RESERVED_CHARACTERS;
 168       fgLookupTable['?'] |= RESERVED_CHARACTERS;
 169       fgLookupTable[':'] |= RESERVED_CHARACTERS;
 170       fgLookupTable['@'] |= RESERVED_CHARACTERS;
 171       fgLookupTable['&'] |= RESERVED_CHARACTERS;
 172       fgLookupTable['='] |= RESERVED_CHARACTERS;
 173       fgLookupTable['+'] |= RESERVED_CHARACTERS;
 174       fgLookupTable['$'] |= RESERVED_CHARACTERS;
 175       fgLookupTable[','] |= RESERVED_CHARACTERS;
 176       fgLookupTable['['] |= RESERVED_CHARACTERS;
 177       fgLookupTable[']'] |= RESERVED_CHARACTERS;
 178 
 179       // Add Mark Characters
 180       fgLookupTable['-'] |= MARK_CHARACTERS;
 181       fgLookupTable['_'] |= MARK_CHARACTERS;
 182       fgLookupTable['.'] |= MARK_CHARACTERS;
 183       fgLookupTable['!'] |= MARK_CHARACTERS;
 184       fgLookupTable['~'] |= MARK_CHARACTERS;
 185       fgLookupTable['*'] |= MARK_CHARACTERS;
 186       fgLookupTable['\''] |= MARK_CHARACTERS;
 187       fgLookupTable['('] |= MARK_CHARACTERS;
 188       fgLookupTable[')'] |= MARK_CHARACTERS;
 189 
 190       // Add Scheme Characters
 191       fgLookupTable['+'] |= SCHEME_CHARACTERS;
 192       fgLookupTable['-'] |= SCHEME_CHARACTERS;
 193       fgLookupTable['.'] |= SCHEME_CHARACTERS;
 194 
 195       // Add Userinfo Characters
 196       fgLookupTable[';'] |= USERINFO_CHARACTERS;
 197       fgLookupTable[':'] |= USERINFO_CHARACTERS;
 198       fgLookupTable['&'] |= USERINFO_CHARACTERS;
 199       fgLookupTable['='] |= USERINFO_CHARACTERS;
 200       fgLookupTable['+'] |= USERINFO_CHARACTERS;
 201       fgLookupTable['$'] |= USERINFO_CHARACTERS;
 202       fgLookupTable[','] |= USERINFO_CHARACTERS;
 203 
 204       // Add Path Characters
 205       fgLookupTable[';'] |= PATH_CHARACTERS;
 206       fgLookupTable['/'] |= PATH_CHARACTERS;
 207       fgLookupTable[':'] |= PATH_CHARACTERS;
 208       fgLookupTable['@'] |= PATH_CHARACTERS;
 209       fgLookupTable['&'] |= PATH_CHARACTERS;
 210       fgLookupTable['='] |= PATH_CHARACTERS;
 211       fgLookupTable['+'] |= PATH_CHARACTERS;
 212       fgLookupTable['$'] |= PATH_CHARACTERS;
 213       fgLookupTable[','] |= PATH_CHARACTERS;
 214   }
 215 
 216   /** Stores the scheme (usually the protocol) for this URI. */
 217   private String m_scheme = null;
 218 
 219   /** If specified, stores the userinfo for this URI; otherwise null */
 220   private String m_userinfo = null;
 221 
 222   /** If specified, stores the host for this URI; otherwise null */
 223   private String m_host = null;
 224 
 225   /** If specified, stores the port for this URI; otherwise -1 */
 226   private int m_port = -1;
 227 
 228   /** If specified, stores the registry based authority for this URI; otherwise -1 */
 229   private String m_regAuthority = null;
 230 
 231   /** If specified, stores the path for this URI; otherwise null */
 232   private String m_path = null;
 233 
 234   /** If specified, stores the query string for this URI; otherwise
 235       null.  */
 236   private String m_queryString = null;
 237 
 238   /** If specified, stores the fragment for this URI; otherwise null */
 239   private String m_fragment = null;
 240 
 241   private static boolean DEBUG = false;
 242 
 243   /**
 244   * Construct a new and uninitialized URI.
 245   */
 246   public URI() {
 247   }
 248 
 249  /**
 250   * Construct a new URI from another URI. All fields for this URI are
 251   * set equal to the fields of the URI passed in.
 252   *
 253   * @param p_other the URI to copy (cannot be null)
 254   */
 255   public URI(URI p_other) {
 256     initialize(p_other);
 257   }
 258 
 259  /**
 260   * Construct a new URI from a URI specification string. If the
 261   * specification follows the "generic URI" syntax, (two slashes
 262   * following the first colon), the specification will be parsed
 263   * accordingly - setting the scheme, userinfo, host,port, path, query
 264   * string and fragment fields as necessary. If the specification does
 265   * not follow the "generic URI" syntax, the specification is parsed
 266   * into a scheme and scheme-specific part (stored as the path) only.
 267   *
 268   * @param p_uriSpec the URI specification string (cannot be null or
 269   *                  empty)
 270   *
 271   * @exception MalformedURIException if p_uriSpec violates any syntax
 272   *                                   rules
 273   */
 274   public URI(String p_uriSpec) throws MalformedURIException {
 275     this((URI)null, p_uriSpec);
 276   }
 277 
 278   /**
 279    * Construct a new URI from a URI specification string. If the
 280    * specification follows the "generic URI" syntax, (two slashes
 281    * following the first colon), the specification will be parsed
 282    * accordingly - setting the scheme, userinfo, host,port, path, query
 283    * string and fragment fields as necessary. If the specification does
 284    * not follow the "generic URI" syntax, the specification is parsed
 285    * into a scheme and scheme-specific part (stored as the path) only.
 286    * Construct a relative URI if boolean is assigned to "true"
 287    * and p_uriSpec is not valid absolute URI, instead of throwing an exception.
 288    *
 289    * @param p_uriSpec the URI specification string (cannot be null or
 290    *                  empty)
 291    * @param allowNonAbsoluteURI true to permit non-absolute URIs,
 292    *                            false otherwise.
 293    *
 294    * @exception MalformedURIException if p_uriSpec violates any syntax
 295    *                                   rules
 296    */
 297   public URI(String p_uriSpec, boolean allowNonAbsoluteURI) throws MalformedURIException {
 298       this((URI)null, p_uriSpec, allowNonAbsoluteURI);
 299   }
 300 
 301  /**
 302   * Construct a new URI from a base URI and a URI specification string.
 303   * The URI specification string may be a relative URI.
 304   *
 305   * @param p_base the base URI (cannot be null if p_uriSpec is null or
 306   *               empty)
 307   * @param p_uriSpec the URI specification string (cannot be null or
 308   *                  empty if p_base is null)
 309   *
 310   * @exception MalformedURIException if p_uriSpec violates any syntax
 311   *                                  rules
 312   */
 313   public URI(URI p_base, String p_uriSpec) throws MalformedURIException {
 314     initialize(p_base, p_uriSpec);
 315   }
 316 
 317   /**
 318    * Construct a new URI from a base URI and a URI specification string.
 319    * The URI specification string may be a relative URI.
 320    * Construct a relative URI if boolean is assigned to "true"
 321    * and p_uriSpec is not valid absolute URI and p_base is null
 322    * instead of throwing an exception.
 323    *
 324    * @param p_base the base URI (cannot be null if p_uriSpec is null or
 325    *               empty)
 326    * @param p_uriSpec the URI specification string (cannot be null or
 327    *                  empty if p_base is null)
 328    * @param allowNonAbsoluteURI true to permit non-absolute URIs,
 329    *                            false otherwise.
 330    *
 331    * @exception MalformedURIException if p_uriSpec violates any syntax
 332    *                                  rules
 333    */
 334   public URI(URI p_base, String p_uriSpec, boolean allowNonAbsoluteURI) throws MalformedURIException {
 335       initialize(p_base, p_uriSpec, allowNonAbsoluteURI);
 336   }
 337 
 338  /**
 339   * Construct a new URI that does not follow the generic URI syntax.
 340   * Only the scheme and scheme-specific part (stored as the path) are
 341   * initialized.
 342   *
 343   * @param p_scheme the URI scheme (cannot be null or empty)
 344   * @param p_schemeSpecificPart the scheme-specific part (cannot be
 345   *                             null or empty)
 346   *
 347   * @exception MalformedURIException if p_scheme violates any
 348   *                                  syntax rules
 349   */
 350   public URI(String p_scheme, String p_schemeSpecificPart)
 351              throws MalformedURIException {
 352     if (p_scheme == null || p_scheme.trim().length() == 0) {
 353       throw new MalformedURIException(
 354             "Cannot construct URI with null/empty scheme!");
 355     }
 356     if (p_schemeSpecificPart == null ||
 357         p_schemeSpecificPart.trim().length() == 0) {
 358       throw new MalformedURIException(
 359           "Cannot construct URI with null/empty scheme-specific part!");
 360     }
 361     setScheme(p_scheme);
 362     setPath(p_schemeSpecificPart);
 363   }
 364 
 365  /**
 366   * Construct a new URI that follows the generic URI syntax from its
 367   * component parts. Each component is validated for syntax and some
 368   * basic semantic checks are performed as well.  See the individual
 369   * setter methods for specifics.
 370   *
 371   * @param p_scheme the URI scheme (cannot be null or empty)
 372   * @param p_host the hostname, IPv4 address or IPv6 reference for the URI
 373   * @param p_path the URI path - if the path contains '?' or '#',
 374   *               then the query string and/or fragment will be
 375   *               set from the path; however, if the query and
 376   *               fragment are specified both in the path and as
 377   *               separate parameters, an exception is thrown
 378   * @param p_queryString the URI query string (cannot be specified
 379   *                      if path is null)
 380   * @param p_fragment the URI fragment (cannot be specified if path
 381   *                   is null)
 382   *
 383   * @exception MalformedURIException if any of the parameters violates
 384   *                                  syntax rules or semantic rules
 385   */
 386   public URI(String p_scheme, String p_host, String p_path,
 387              String p_queryString, String p_fragment)
 388          throws MalformedURIException {
 389     this(p_scheme, null, p_host, -1, p_path, p_queryString, p_fragment);
 390   }
 391 
 392  /**
 393   * Construct a new URI that follows the generic URI syntax from its
 394   * component parts. Each component is validated for syntax and some
 395   * basic semantic checks are performed as well.  See the individual
 396   * setter methods for specifics.
 397   *
 398   * @param p_scheme the URI scheme (cannot be null or empty)
 399   * @param p_userinfo the URI userinfo (cannot be specified if host
 400   *                   is null)
 401   * @param p_host the hostname, IPv4 address or IPv6 reference for the URI
 402   * @param p_port the URI port (may be -1 for "unspecified"; cannot
 403   *               be specified if host is null)
 404   * @param p_path the URI path - if the path contains '?' or '#',
 405   *               then the query string and/or fragment will be
 406   *               set from the path; however, if the query and
 407   *               fragment are specified both in the path and as
 408   *               separate parameters, an exception is thrown
 409   * @param p_queryString the URI query string (cannot be specified
 410   *                      if path is null)
 411   * @param p_fragment the URI fragment (cannot be specified if path
 412   *                   is null)
 413   *
 414   * @exception MalformedURIException if any of the parameters violates
 415   *                                  syntax rules or semantic rules
 416   */
 417   public URI(String p_scheme, String p_userinfo,
 418              String p_host, int p_port, String p_path,
 419              String p_queryString, String p_fragment)
 420          throws MalformedURIException {
 421     if (p_scheme == null || p_scheme.trim().length() == 0) {
 422       throw new MalformedURIException("Scheme is required!");
 423     }
 424 
 425     if (p_host == null) {
 426       if (p_userinfo != null) {
 427         throw new MalformedURIException(
 428              "Userinfo may not be specified if host is not specified!");
 429       }
 430       if (p_port != -1) {
 431         throw new MalformedURIException(
 432              "Port may not be specified if host is not specified!");
 433       }
 434     }
 435 
 436     if (p_path != null) {
 437       if (p_path.indexOf('?') != -1 && p_queryString != null) {
 438         throw new MalformedURIException(
 439           "Query string cannot be specified in path and query string!");
 440       }
 441 
 442       if (p_path.indexOf('#') != -1 && p_fragment != null) {
 443         throw new MalformedURIException(
 444           "Fragment cannot be specified in both the path and fragment!");
 445       }
 446     }
 447 
 448     setScheme(p_scheme);
 449     setHost(p_host);
 450     setPort(p_port);
 451     setUserinfo(p_userinfo);
 452     setPath(p_path);
 453     setQueryString(p_queryString);
 454     setFragment(p_fragment);
 455   }
 456 
 457  /**
 458   * Initialize all fields of this URI from another URI.
 459   *
 460   * @param p_other the URI to copy (cannot be null)
 461   */
 462   private void initialize(URI p_other) {
 463     m_scheme = p_other.getScheme();
 464     m_userinfo = p_other.getUserinfo();
 465     m_host = p_other.getHost();
 466     m_port = p_other.getPort();
 467     m_regAuthority = p_other.getRegBasedAuthority();
 468     m_path = p_other.getPath();
 469     m_queryString = p_other.getQueryString();
 470     m_fragment = p_other.getFragment();
 471   }
 472 
 473   /**
 474    * Initializes this URI from a base URI and a URI specification string.
 475    * See RFC 2396 Section 4 and Appendix B for specifications on parsing
 476    * the URI and Section 5 for specifications on resolving relative URIs
 477    * and relative paths.
 478    *
 479    * @param p_base the base URI (may be null if p_uriSpec is an absolute
 480    *               URI)
 481    * @param p_uriSpec the URI spec string which may be an absolute or
 482    *                  relative URI (can only be null/empty if p_base
 483    *                  is not null)
 484    * @param allowNonAbsoluteURI true to permit non-absolute URIs,
 485    *                         in case of relative URI, false otherwise.
 486    *
 487    * @exception MalformedURIException if p_base is null and p_uriSpec
 488    *                                  is not an absolute URI or if
 489    *                                  p_uriSpec violates syntax rules
 490    */
 491   private void initialize(URI p_base, String p_uriSpec, boolean allowNonAbsoluteURI)
 492       throws MalformedURIException {
 493 
 494       String uriSpec = p_uriSpec;
 495       int uriSpecLen = (uriSpec != null) ? uriSpec.length() : 0;
 496 
 497       if (p_base == null && uriSpecLen == 0) {
 498           if (allowNonAbsoluteURI) {
 499               m_path = "";
 500               return;
 501           }
 502           throw new MalformedURIException("Cannot initialize URI with empty parameters.");
 503       }
 504 
 505       // just make a copy of the base if spec is empty
 506       if (uriSpecLen == 0) {
 507           initialize(p_base);
 508           return;
 509       }
 510 
 511       int index = 0;
 512 
 513       // Check for scheme, which must be before '/', '?' or '#'.
 514       int colonIdx = uriSpec.indexOf(':');
 515       if (colonIdx != -1) {
 516           final int searchFrom = colonIdx - 1;
 517           // search backwards starting from character before ':'.
 518           int slashIdx = uriSpec.lastIndexOf('/', searchFrom);
 519           int queryIdx = uriSpec.lastIndexOf('?', searchFrom);
 520           int fragmentIdx = uriSpec.lastIndexOf('#', searchFrom);
 521 
 522           if (colonIdx == 0 || slashIdx != -1 ||
 523               queryIdx != -1 || fragmentIdx != -1) {
 524               // A standalone base is a valid URI according to spec
 525               if (colonIdx == 0 || (p_base == null && fragmentIdx != 0 && !allowNonAbsoluteURI)) {
 526                   throw new MalformedURIException("No scheme found in URI.");
 527               }
 528           }
 529           else {
 530               initializeScheme(uriSpec);
 531               index = m_scheme.length()+1;
 532 
 533               // Neither 'scheme:' or 'scheme:#fragment' are valid URIs.
 534               if (colonIdx == uriSpecLen - 1 || uriSpec.charAt(colonIdx+1) == '#') {
 535                   throw new MalformedURIException("Scheme specific part cannot be empty.");
 536               }
 537           }
 538       }
 539       else if (p_base == null && uriSpec.indexOf('#') != 0 && !allowNonAbsoluteURI) {
 540           throw new MalformedURIException("No scheme found in URI.");
 541       }
 542 
 543       // Two slashes means we may have authority, but definitely means we're either
 544       // matching net_path or abs_path. These two productions are ambiguous in that
 545       // every net_path (except those containing an IPv6Reference) is an abs_path.
 546       // RFC 2396 resolves this ambiguity by applying a greedy left most matching rule.
 547       // Try matching net_path first, and if that fails we don't have authority so
 548       // then attempt to match abs_path.
 549       //
 550       // net_path = "//" authority [ abs_path ]
 551       // abs_path = "/"  path_segments
 552       if (((index+1) < uriSpecLen) &&
 553           (uriSpec.charAt(index) == '/' && uriSpec.charAt(index+1) == '/')) {
 554           index += 2;
 555           int startPos = index;
 556 
 557           // Authority will be everything up to path, query or fragment
 558           char testChar = '\0';
 559           while (index < uriSpecLen) {
 560               testChar = uriSpec.charAt(index);
 561               if (testChar == '/' || testChar == '?' || testChar == '#') {
 562                   break;
 563               }
 564               index++;
 565           }
 566 
 567           // Attempt to parse authority. If the section is an empty string
 568           // this is a valid server based authority, so set the host to this
 569           // value.
 570           if (index > startPos) {
 571               // If we didn't find authority we need to back up. Attempt to
 572               // match against abs_path next.
 573               if (!initializeAuthority(uriSpec.substring(startPos, index))) {
 574                   index = startPos - 2;
 575               }
 576           }
 577           else {
 578               m_host = "";
 579           }
 580       }
 581 
 582       initializePath(uriSpec, index);
 583 
 584       // Resolve relative URI to base URI - see RFC 2396 Section 5.2
 585       // In some cases, it might make more sense to throw an exception
 586       // (when scheme is specified is the string spec and the base URI
 587       // is also specified, for example), but we're just following the
 588       // RFC specifications
 589       if (p_base != null) {
 590           absolutize(p_base);
 591       }
 592   }
 593 
 594  /**
 595   * Initializes this URI from a base URI and a URI specification string.
 596   * See RFC 2396 Section 4 and Appendix B for specifications on parsing
 597   * the URI and Section 5 for specifications on resolving relative URIs
 598   * and relative paths.
 599   *
 600   * @param p_base the base URI (may be null if p_uriSpec is an absolute
 601   *               URI)
 602   * @param p_uriSpec the URI spec string which may be an absolute or
 603   *                  relative URI (can only be null/empty if p_base
 604   *                  is not null)
 605   *
 606   * @exception MalformedURIException if p_base is null and p_uriSpec
 607   *                                  is not an absolute URI or if
 608   *                                  p_uriSpec violates syntax rules
 609   */
 610   private void initialize(URI p_base, String p_uriSpec)
 611                          throws MalformedURIException {
 612 
 613     String uriSpec = p_uriSpec;
 614     int uriSpecLen = (uriSpec != null) ? uriSpec.length() : 0;
 615 
 616     if (p_base == null && uriSpecLen == 0) {
 617       throw new MalformedURIException(
 618                   "Cannot initialize URI with empty parameters.");
 619     }
 620 
 621     // just make a copy of the base if spec is empty
 622     if (uriSpecLen == 0) {
 623       initialize(p_base);
 624       return;
 625     }
 626 
 627     int index = 0;
 628 
 629     // Check for scheme, which must be before '/', '?' or '#'.
 630     int colonIdx = uriSpec.indexOf(':');
 631     if (colonIdx != -1) {
 632         final int searchFrom = colonIdx - 1;
 633         // search backwards starting from character before ':'.
 634         int slashIdx = uriSpec.lastIndexOf('/', searchFrom);
 635         int queryIdx = uriSpec.lastIndexOf('?', searchFrom);
 636         int fragmentIdx = uriSpec.lastIndexOf('#', searchFrom);
 637 
 638         if (colonIdx == 0 || slashIdx != -1 ||
 639             queryIdx != -1 || fragmentIdx != -1) {
 640             // A standalone base is a valid URI according to spec
 641             if (colonIdx == 0 || (p_base == null && fragmentIdx != 0)) {
 642                 throw new MalformedURIException("No scheme found in URI.");
 643             }
 644         }
 645         else {
 646             initializeScheme(uriSpec);
 647             index = m_scheme.length()+1;
 648 
 649             // Neither 'scheme:' or 'scheme:#fragment' are valid URIs.
 650             if (colonIdx == uriSpecLen - 1 || uriSpec.charAt(colonIdx+1) == '#') {
 651                 throw new MalformedURIException("Scheme specific part cannot be empty.");
 652             }
 653         }
 654     }
 655     else if (p_base == null && uriSpec.indexOf('#') != 0) {
 656         throw new MalformedURIException("No scheme found in URI.");
 657     }
 658 
 659     // Two slashes means we may have authority, but definitely means we're either
 660     // matching net_path or abs_path. These two productions are ambiguous in that
 661     // every net_path (except those containing an IPv6Reference) is an abs_path.
 662     // RFC 2396 resolves this ambiguity by applying a greedy left most matching rule.
 663     // Try matching net_path first, and if that fails we don't have authority so
 664     // then attempt to match abs_path.
 665     //
 666     // net_path = "//" authority [ abs_path ]
 667     // abs_path = "/"  path_segments
 668     if (((index+1) < uriSpecLen) &&
 669         (uriSpec.charAt(index) == '/' && uriSpec.charAt(index+1) == '/')) {
 670       index += 2;
 671       int startPos = index;
 672 
 673       // Authority will be everything up to path, query or fragment
 674       char testChar = '\0';
 675       while (index < uriSpecLen) {
 676         testChar = uriSpec.charAt(index);
 677         if (testChar == '/' || testChar == '?' || testChar == '#') {
 678           break;
 679         }
 680         index++;
 681       }
 682 
 683       // Attempt to parse authority. If the section is an empty string
 684       // this is a valid server based authority, so set the host to this
 685       // value.
 686       if (index > startPos) {
 687         // If we didn't find authority we need to back up. Attempt to
 688         // match against abs_path next.
 689         if (!initializeAuthority(uriSpec.substring(startPos, index))) {
 690           index = startPos - 2;
 691         }
 692       }
 693       else {
 694         m_host = "";
 695       }
 696     }
 697 
 698     initializePath(uriSpec, index);
 699 
 700     // Resolve relative URI to base URI - see RFC 2396 Section 5.2
 701     // In some cases, it might make more sense to throw an exception
 702     // (when scheme is specified is the string spec and the base URI
 703     // is also specified, for example), but we're just following the
 704     // RFC specifications
 705     if (p_base != null) {
 706         absolutize(p_base);
 707     }
 708   }
 709 
 710   /**
 711    * Absolutize URI with given base URI.
 712    *
 713    * @param p_base base URI for absolutization
 714    */
 715   public void absolutize(URI p_base) {
 716 
 717       // check to see if this is the current doc - RFC 2396 5.2 #2
 718       // note that this is slightly different from the RFC spec in that
 719       // we don't include the check for query string being null
 720       // - this handles cases where the urispec is just a query
 721       // string or a fragment (e.g. "?y" or "#s") -
 722       // see <http://www.ics.uci.edu/~fielding/url/test1.html> which
 723       // identified this as a bug in the RFC
 724       if (m_path.length() == 0 && m_scheme == null &&
 725           m_host == null && m_regAuthority == null) {
 726           m_scheme = p_base.getScheme();
 727           m_userinfo = p_base.getUserinfo();
 728           m_host = p_base.getHost();
 729           m_port = p_base.getPort();
 730           m_regAuthority = p_base.getRegBasedAuthority();
 731           m_path = p_base.getPath();
 732 
 733           if (m_queryString == null) {
 734               m_queryString = p_base.getQueryString();
 735 
 736               if (m_fragment == null) {
 737                   m_fragment = p_base.getFragment();
 738               }
 739           }
 740           return;
 741       }
 742 
 743       // check for scheme - RFC 2396 5.2 #3
 744       // if we found a scheme, it means absolute URI, so we're done
 745       if (m_scheme == null) {
 746           m_scheme = p_base.getScheme();
 747       }
 748       else {
 749           return;
 750       }
 751 
 752       // check for authority - RFC 2396 5.2 #4
 753       // if we found a host, then we've got a network path, so we're done
 754       if (m_host == null && m_regAuthority == null) {
 755           m_userinfo = p_base.getUserinfo();
 756           m_host = p_base.getHost();
 757           m_port = p_base.getPort();
 758           m_regAuthority = p_base.getRegBasedAuthority();
 759       }
 760       else {
 761           return;
 762       }
 763 
 764       // check for absolute path - RFC 2396 5.2 #5
 765       if (m_path.length() > 0 &&
 766               m_path.startsWith("/")) {
 767           return;
 768       }
 769 
 770       // if we get to this point, we need to resolve relative path
 771       // RFC 2396 5.2 #6
 772       String path = "";
 773       String basePath = p_base.getPath();
 774 
 775       // 6a - get all but the last segment of the base URI path
 776       if (basePath != null && basePath.length() > 0) {
 777           int lastSlash = basePath.lastIndexOf('/');
 778           if (lastSlash != -1) {
 779               path = basePath.substring(0, lastSlash+1);
 780           }
 781       }
 782       else if (m_path.length() > 0) {
 783           path = "/";
 784       }
 785 
 786       // 6b - append the relative URI path
 787       path = path.concat(m_path);
 788 
 789       // 6c - remove all "./" where "." is a complete path segment
 790       int index = -1;
 791       while ((index = path.indexOf("/./")) != -1) {
 792           path = path.substring(0, index+1).concat(path.substring(index+3));
 793       }
 794 
 795       // 6d - remove "." if path ends with "." as a complete path segment
 796       if (path.endsWith("/.")) {
 797           path = path.substring(0, path.length()-1);
 798       }
 799 
 800       // 6e - remove all "<segment>/../" where "<segment>" is a complete
 801       // path segment not equal to ".."
 802       index = 1;
 803       int segIndex = -1;
 804       String tempString = null;
 805 
 806       while ((index = path.indexOf("/../", index)) > 0) {
 807           tempString = path.substring(0, path.indexOf("/../"));
 808           segIndex = tempString.lastIndexOf('/');
 809           if (segIndex != -1) {
 810               if (!tempString.substring(segIndex).equals("..")) {
 811                   path = path.substring(0, segIndex+1).concat(path.substring(index+4));
 812                   index = segIndex;
 813               }
 814               else {
 815                   index += 4;
 816               }
 817           }
 818           else {
 819               index += 4;
 820           }
 821       }
 822 
 823       // 6f - remove ending "<segment>/.." where "<segment>" is a
 824       // complete path segment
 825       if (path.endsWith("/..")) {
 826           tempString = path.substring(0, path.length()-3);
 827           segIndex = tempString.lastIndexOf('/');
 828           if (segIndex != -1) {
 829               path = path.substring(0, segIndex+1);
 830           }
 831       }
 832       m_path = path;
 833   }
 834 
 835  /**
 836   * Initialize the scheme for this URI from a URI string spec.
 837   *
 838   * @param p_uriSpec the URI specification (cannot be null)
 839   *
 840   * @exception MalformedURIException if URI does not have a conformant
 841   *                                  scheme
 842   */
 843   private void initializeScheme(String p_uriSpec)
 844                  throws MalformedURIException {
 845     int uriSpecLen = p_uriSpec.length();
 846     int index = 0;
 847     String scheme = null;
 848     char testChar = '\0';
 849 
 850     while (index < uriSpecLen) {
 851       testChar = p_uriSpec.charAt(index);
 852       if (testChar == ':' || testChar == '/' ||
 853           testChar == '?' || testChar == '#') {
 854         break;
 855       }
 856       index++;
 857     }
 858     scheme = p_uriSpec.substring(0, index);
 859 
 860     if (scheme.length() == 0) {
 861       throw new MalformedURIException("No scheme found in URI.");
 862     }
 863     else {
 864       setScheme(scheme);
 865     }
 866   }
 867 
 868  /**
 869   * Initialize the authority (either server or registry based)
 870   * for this URI from a URI string spec.
 871   *
 872   * @param p_uriSpec the URI specification (cannot be null)
 873   *
 874   * @return true if the given string matched server or registry
 875   * based authority
 876   */
 877   private boolean initializeAuthority(String p_uriSpec) {
 878 
 879     int index = 0;
 880     int start = 0;
 881     int end = p_uriSpec.length();
 882 
 883     char testChar = '\0';
 884     String userinfo = null;
 885 
 886     // userinfo is everything up to @
 887     if (p_uriSpec.indexOf('@', start) != -1) {
 888       while (index < end) {
 889         testChar = p_uriSpec.charAt(index);
 890         if (testChar == '@') {
 891           break;
 892         }
 893         index++;
 894       }
 895       userinfo = p_uriSpec.substring(start, index);
 896       index++;
 897     }
 898 
 899     // host is everything up to last ':', or up to
 900     // and including ']' if followed by ':'.
 901     String host = null;
 902     start = index;
 903     boolean hasPort = false;
 904     if (index < end) {
 905       if (p_uriSpec.charAt(start) == '[') {
 906         int bracketIndex = p_uriSpec.indexOf(']', start);
 907         index = (bracketIndex != -1) ? bracketIndex : end;
 908         if (index+1 < end && p_uriSpec.charAt(index+1) == ':') {
 909           ++index;
 910           hasPort = true;
 911         }
 912         else {
 913           index = end;
 914         }
 915       }
 916       else {
 917         int colonIndex = p_uriSpec.lastIndexOf(':', end);
 918         index = (colonIndex > start) ? colonIndex : end;
 919         hasPort = (index != end);
 920       }
 921     }
 922     host = p_uriSpec.substring(start, index);
 923     int port = -1;
 924     if (host.length() > 0) {
 925       // port
 926       if (hasPort) {
 927         index++;
 928         start = index;
 929         while (index < end) {
 930           index++;
 931         }
 932         String portStr = p_uriSpec.substring(start, index);
 933         if (portStr.length() > 0) {
 934           // REVISIT: Remove this code.
 935           /** for (int i = 0; i < portStr.length(); i++) {
 936             if (!isDigit(portStr.charAt(i))) {
 937               throw new MalformedURIException(
 938                    portStr +
 939                    " is invalid. Port should only contain digits!");
 940             }
 941           }**/
 942           // REVISIT: Remove this code.
 943           // Store port value as string instead of integer.
 944           try {
 945             port = Integer.parseInt(portStr);
 946             if (port == -1) --port;
 947           }
 948           catch (NumberFormatException nfe) {
 949             port = -2;
 950           }
 951         }
 952       }
 953     }
 954 
 955     if (isValidServerBasedAuthority(host, port, userinfo)) {
 956       m_host = host;
 957       m_port = port;
 958       m_userinfo = userinfo;
 959       return true;
 960     }
 961     // Note: Registry based authority is being removed from a
 962     // new spec for URI which would obsolete RFC 2396. If the
 963     // spec is added to XML errata, processing of reg_name
 964     // needs to be removed. - mrglavas.
 965     else if (isValidRegistryBasedAuthority(p_uriSpec)) {
 966       m_regAuthority = p_uriSpec;
 967       return true;
 968     }
 969     return false;
 970   }
 971 
 972   /**
 973    * Determines whether the components host, port, and user info
 974    * are valid as a server authority.
 975    *
 976    * @param host the host component of authority
 977    * @param port the port number component of authority
 978    * @param userinfo the user info component of authority
 979    *
 980    * @return true if the given host, port, and userinfo compose
 981    * a valid server authority
 982    */
 983   private boolean isValidServerBasedAuthority(String host, int port, String userinfo) {
 984 
 985     // Check if the host is well formed.
 986     if (!isWellFormedAddress(host)) {
 987       return false;
 988     }
 989 
 990     // Check that port is well formed if it exists.
 991     // REVISIT: There's no restriction on port value ranges, but
 992     // perform the same check as in setPort to be consistent. Pass
 993     // in a string to this method instead of an integer.
 994     if (port < -1 || port > 65535) {
 995       return false;
 996     }
 997 
 998     // Check that userinfo is well formed if it exists.
 999     if (userinfo != null) {
1000       // Userinfo can contain alphanumerics, mark characters, escaped
1001       // and ';',':','&','=','+','$',','
1002       int index = 0;
1003       int end = userinfo.length();
1004       char testChar = '\0';
1005       while (index < end) {
1006         testChar = userinfo.charAt(index);
1007         if (testChar == '%') {
1008           if (index+2 >= end ||
1009             !isHex(userinfo.charAt(index+1)) ||
1010             !isHex(userinfo.charAt(index+2))) {
1011             return false;
1012           }
1013           index += 2;
1014         }
1015         else if (!isUserinfoCharacter(testChar)) {
1016           return false;
1017         }
1018         ++index;
1019       }
1020     }
1021     return true;
1022   }
1023 
1024   /**
1025    * Determines whether the given string is a registry based authority.
1026    *
1027    * @param authority the authority component of a URI
1028    *
1029    * @return true if the given string is a registry based authority
1030    */
1031   private boolean isValidRegistryBasedAuthority(String authority) {
1032     int index = 0;
1033     int end = authority.length();
1034     char testChar;
1035 
1036     while (index < end) {
1037       testChar = authority.charAt(index);
1038 
1039       // check for valid escape sequence
1040       if (testChar == '%') {
1041         if (index+2 >= end ||
1042             !isHex(authority.charAt(index+1)) ||
1043             !isHex(authority.charAt(index+2))) {
1044             return false;
1045         }
1046         index += 2;
1047       }
1048       // can check against path characters because the set
1049       // is the same except for '/' which we've already excluded.
1050       else if (!isPathCharacter(testChar)) {
1051         return false;
1052       }
1053       ++index;
1054     }
1055     return true;
1056   }
1057 
1058  /**
1059   * Initialize the path for this URI from a URI string spec.
1060   *
1061   * @param p_uriSpec the URI specification (cannot be null)
1062   * @param p_nStartIndex the index to begin scanning from
1063   *
1064   * @exception MalformedURIException if p_uriSpec violates syntax rules
1065   */
1066   private void initializePath(String p_uriSpec, int p_nStartIndex)
1067                  throws MalformedURIException {
1068     if (p_uriSpec == null) {
1069       throw new MalformedURIException(
1070                 "Cannot initialize path from null string!");
1071     }
1072 
1073     int index = p_nStartIndex;
1074     int start = p_nStartIndex;
1075     int end = p_uriSpec.length();
1076     char testChar = '\0';
1077 
1078     // path - everything up to query string or fragment
1079     if (start < end) {
1080         // RFC 2732 only allows '[' and ']' to appear in the opaque part.
1081         if (getScheme() == null || p_uriSpec.charAt(start) == '/') {
1082 
1083             // Scan path.
1084             // abs_path = "/"  path_segments
1085             // rel_path = rel_segment [ abs_path ]
1086             while (index < end) {
1087                 testChar = p_uriSpec.charAt(index);
1088 
1089                 // check for valid escape sequence
1090                 if (testChar == '%') {
1091                     if (index+2 >= end ||
1092                     !isHex(p_uriSpec.charAt(index+1)) ||
1093                     !isHex(p_uriSpec.charAt(index+2))) {
1094                         throw new MalformedURIException(
1095                             "Path contains invalid escape sequence!");
1096                     }
1097                     index += 2;
1098                 }
1099                 // Path segments cannot contain '[' or ']' since pchar
1100                 // production was not changed by RFC 2732.
1101                 else if (!isPathCharacter(testChar)) {
1102                     if (testChar == '?' || testChar == '#') {
1103                         break;
1104                     }
1105                     throw new MalformedURIException(
1106                         "Path contains invalid character: " + testChar);
1107                 }
1108                 ++index;
1109             }
1110         }
1111         else {
1112 
1113             // Scan opaque part.
1114             // opaque_part = uric_no_slash *uric
1115             while (index < end) {
1116                 testChar = p_uriSpec.charAt(index);
1117 
1118                 if (testChar == '?' || testChar == '#') {
1119                     break;
1120                 }
1121 
1122                 // check for valid escape sequence
1123                 if (testChar == '%') {
1124                     if (index+2 >= end ||
1125                     !isHex(p_uriSpec.charAt(index+1)) ||
1126                     !isHex(p_uriSpec.charAt(index+2))) {
1127                         throw new MalformedURIException(
1128                             "Opaque part contains invalid escape sequence!");
1129                     }
1130                     index += 2;
1131                 }
1132                 // If the scheme specific part is opaque, it can contain '['
1133                 // and ']'. uric_no_slash wasn't modified by RFC 2732, which
1134                 // I've interpreted as an error in the spec, since the
1135                 // production should be equivalent to (uric - '/'), and uric
1136                 // contains '[' and ']'. - mrglavas
1137                 else if (!isURICharacter(testChar)) {
1138                     throw new MalformedURIException(
1139                         "Opaque part contains invalid character: " + testChar);
1140                 }
1141                 ++index;
1142             }
1143         }
1144     }
1145     m_path = p_uriSpec.substring(start, index);
1146 
1147     // query - starts with ? and up to fragment or end
1148     if (testChar == '?') {
1149       index++;
1150       start = index;
1151       while (index < end) {
1152         testChar = p_uriSpec.charAt(index);
1153         if (testChar == '#') {
1154           break;
1155         }
1156         if (testChar == '%') {
1157            if (index+2 >= end ||
1158               !isHex(p_uriSpec.charAt(index+1)) ||
1159               !isHex(p_uriSpec.charAt(index+2))) {
1160             throw new MalformedURIException(
1161                     "Query string contains invalid escape sequence!");
1162            }
1163            index += 2;
1164         }
1165         else if (!isURICharacter(testChar)) {
1166           throw new MalformedURIException(
1167                 "Query string contains invalid character: " + testChar);
1168         }
1169         index++;
1170       }
1171       m_queryString = p_uriSpec.substring(start, index);
1172     }
1173 
1174     // fragment - starts with #
1175     if (testChar == '#') {
1176       index++;
1177       start = index;
1178       while (index < end) {
1179         testChar = p_uriSpec.charAt(index);
1180 
1181         if (testChar == '%') {
1182            if (index+2 >= end ||
1183               !isHex(p_uriSpec.charAt(index+1)) ||
1184               !isHex(p_uriSpec.charAt(index+2))) {
1185             throw new MalformedURIException(
1186                     "Fragment contains invalid escape sequence!");
1187            }
1188            index += 2;
1189         }
1190         else if (!isURICharacter(testChar)) {
1191           throw new MalformedURIException(
1192                 "Fragment contains invalid character: "+testChar);
1193         }
1194         index++;
1195       }
1196       m_fragment = p_uriSpec.substring(start, index);
1197     }
1198   }
1199 
1200  /**
1201   * Get the scheme for this URI.
1202   *
1203   * @return the scheme for this URI
1204   */
1205   public String getScheme() {
1206     return m_scheme;
1207   }
1208 
1209  /**
1210   * Get the scheme-specific part for this URI (everything following the
1211   * scheme and the first colon). See RFC 2396 Section 5.2 for spec.
1212   *
1213   * @return the scheme-specific part for this URI
1214   */
1215   public String getSchemeSpecificPart() {
1216     final StringBuilder schemespec = new StringBuilder();
1217 
1218     if (m_host != null || m_regAuthority != null) {
1219       schemespec.append("//");
1220 
1221       // Server based authority.
1222       if (m_host != null) {
1223 
1224         if (m_userinfo != null) {
1225           schemespec.append(m_userinfo);
1226           schemespec.append('@');
1227         }
1228 
1229         schemespec.append(m_host);
1230 
1231         if (m_port != -1) {
1232           schemespec.append(':');
1233           schemespec.append(m_port);
1234         }
1235       }
1236       // Registry based authority.
1237       else {
1238         schemespec.append(m_regAuthority);
1239       }
1240     }
1241 
1242     if (m_path != null) {
1243       schemespec.append((m_path));
1244     }
1245 
1246     if (m_queryString != null) {
1247       schemespec.append('?');
1248       schemespec.append(m_queryString);
1249     }
1250 
1251     if (m_fragment != null) {
1252       schemespec.append('#');
1253       schemespec.append(m_fragment);
1254     }
1255 
1256     return schemespec.toString();
1257   }
1258 
1259  /**
1260   * Get the userinfo for this URI.
1261   *
1262   * @return the userinfo for this URI (null if not specified).
1263   */
1264   public String getUserinfo() {
1265     return m_userinfo;
1266   }
1267 
1268   /**
1269   * Get the host for this URI.
1270   *
1271   * @return the host for this URI (null if not specified).
1272   */
1273   public String getHost() {
1274     return m_host;
1275   }
1276 
1277  /**
1278   * Get the port for this URI.
1279   *
1280   * @return the port for this URI (-1 if not specified).
1281   */
1282   public int getPort() {
1283     return m_port;
1284   }
1285 
1286   /**
1287    * Get the registry based authority for this URI.
1288    *
1289    * @return the registry based authority (null if not specified).
1290    */
1291   public String getRegBasedAuthority() {
1292     return m_regAuthority;
1293   }
1294 
1295   /**
1296    * Get the authority for this URI.
1297    *
1298    * @return the authority
1299    */
1300   public String getAuthority() {
1301       final StringBuilder authority = new StringBuilder();
1302       if (m_host != null || m_regAuthority != null) {
1303           authority.append("//");
1304 
1305           // Server based authority.
1306           if (m_host != null) {
1307 
1308               if (m_userinfo != null) {
1309                   authority.append(m_userinfo);
1310                   authority.append('@');
1311               }
1312 
1313               authority.append(m_host);
1314 
1315               if (m_port != -1) {
1316                   authority.append(':');
1317                   authority.append(m_port);
1318               }
1319           }
1320           // Registry based authority.
1321           else {
1322               authority.append(m_regAuthority);
1323           }
1324       }
1325       return authority.toString();
1326   }
1327 
1328  /**
1329   * Get the path for this URI (optionally with the query string and
1330   * fragment).
1331   *
1332   * @param p_includeQueryString if true (and query string is not null),
1333   *                             then a "?" followed by the query string
1334   *                             will be appended
1335   * @param p_includeFragment if true (and fragment is not null),
1336   *                             then a "#" followed by the fragment
1337   *                             will be appended
1338   *
1339   * @return the path for this URI possibly including the query string
1340   *         and fragment
1341   */
1342   public String getPath(boolean p_includeQueryString,
1343                         boolean p_includeFragment) {
1344     final StringBuilder pathString = new StringBuilder(m_path);
1345 
1346     if (p_includeQueryString && m_queryString != null) {
1347       pathString.append('?');
1348       pathString.append(m_queryString);
1349     }
1350 
1351     if (p_includeFragment && m_fragment != null) {
1352       pathString.append('#');
1353       pathString.append(m_fragment);
1354     }
1355     return pathString.toString();
1356   }
1357 
1358  /**
1359   * Get the path for this URI. Note that the value returned is the path
1360   * only and does not include the query string or fragment.
1361   *
1362   * @return the path for this URI.
1363   */
1364   public String getPath() {
1365     return m_path;
1366   }
1367 
1368  /**
1369   * Get the query string for this URI.
1370   *
1371   * @return the query string for this URI. Null is returned if there
1372   *         was no "?" in the URI spec, empty string if there was a
1373   *         "?" but no query string following it.
1374   */
1375   public String getQueryString() {
1376     return m_queryString;
1377   }
1378 
1379  /**
1380   * Get the fragment for this URI.
1381   *
1382   * @return the fragment for this URI. Null is returned if there
1383   *         was no "#" in the URI spec, empty string if there was a
1384   *         "#" but no fragment following it.
1385   */
1386   public String getFragment() {
1387     return m_fragment;
1388   }
1389 
1390  /**
1391   * Set the scheme for this URI. The scheme is converted to lowercase
1392   * before it is set.
1393   *
1394   * @param p_scheme the scheme for this URI (cannot be null)
1395   *
1396   * @exception MalformedURIException if p_scheme is not a conformant
1397   *                                  scheme name
1398   */
1399   public void setScheme(String p_scheme) throws MalformedURIException {
1400     if (p_scheme == null) {
1401       throw new MalformedURIException(
1402                 "Cannot set scheme from null string!");
1403     }
1404     if (!isConformantSchemeName(p_scheme)) {
1405       throw new MalformedURIException("The scheme is not conformant.");
1406     }
1407 
1408     m_scheme = p_scheme.toLowerCase();
1409   }
1410 
1411  /**
1412   * Set the userinfo for this URI. If a non-null value is passed in and
1413   * the host value is null, then an exception is thrown.
1414   *
1415   * @param p_userinfo the userinfo for this URI
1416   *
1417   * @exception MalformedURIException if p_userinfo contains invalid
1418   *                                  characters
1419   */
1420   public void setUserinfo(String p_userinfo) throws MalformedURIException {
1421     if (p_userinfo == null) {
1422       m_userinfo = null;
1423       return;
1424     }
1425     else {
1426       if (m_host == null) {
1427         throw new MalformedURIException(
1428                      "Userinfo cannot be set when host is null!");
1429       }
1430 
1431       // userinfo can contain alphanumerics, mark characters, escaped
1432       // and ';',':','&','=','+','$',','
1433       int index = 0;
1434       int end = p_userinfo.length();
1435       char testChar = '\0';
1436       while (index < end) {
1437         testChar = p_userinfo.charAt(index);
1438         if (testChar == '%') {
1439           if (index+2 >= end ||
1440               !isHex(p_userinfo.charAt(index+1)) ||
1441               !isHex(p_userinfo.charAt(index+2))) {
1442             throw new MalformedURIException(
1443                   "Userinfo contains invalid escape sequence!");
1444           }
1445         }
1446         else if (!isUserinfoCharacter(testChar)) {
1447           throw new MalformedURIException(
1448                   "Userinfo contains invalid character:"+testChar);
1449         }
1450         index++;
1451       }
1452     }
1453     m_userinfo = p_userinfo;
1454   }
1455 
1456  /**
1457   * <p>Set the host for this URI. If null is passed in, the userinfo
1458   * field is also set to null and the port is set to -1.</p>
1459   *
1460   * <p>Note: This method overwrites registry based authority if it
1461   * previously existed in this URI.</p>
1462   *
1463   * @param p_host the host for this URI
1464   *
1465   * @exception MalformedURIException if p_host is not a valid IP
1466   *                                  address or DNS hostname.
1467   */
1468   public void setHost(String p_host) throws MalformedURIException {
1469     if (p_host == null || p_host.length() == 0) {
1470       if (p_host != null) {
1471         m_regAuthority = null;
1472       }
1473       m_host = p_host;
1474       m_userinfo = null;
1475       m_port = -1;
1476       return;
1477     }
1478     else if (!isWellFormedAddress(p_host)) {
1479       throw new MalformedURIException("Host is not a well formed address!");
1480     }
1481     m_host = p_host;
1482     m_regAuthority = null;
1483   }
1484 
1485  /**
1486   * Set the port for this URI. -1 is used to indicate that the port is
1487   * not specified, otherwise valid port numbers are  between 0 and 65535.
1488   * If a valid port number is passed in and the host field is null,
1489   * an exception is thrown.
1490   *
1491   * @param p_port the port number for this URI
1492   *
1493   * @exception MalformedURIException if p_port is not -1 and not a
1494   *                                  valid port number
1495   */
1496   public void setPort(int p_port) throws MalformedURIException {
1497     if (p_port >= 0 && p_port <= 65535) {
1498       if (m_host == null) {
1499         throw new MalformedURIException(
1500                       "Port cannot be set when host is null!");
1501       }
1502     }
1503     else if (p_port != -1) {
1504       throw new MalformedURIException("Invalid port number!");
1505     }
1506     m_port = p_port;
1507   }
1508 
1509   /**
1510    * <p>Sets the registry based authority for this URI.</p>
1511    *
1512    * <p>Note: This method overwrites server based authority
1513    * if it previously existed in this URI.</p>
1514    *
1515    * @param authority the registry based authority for this URI
1516    *
1517    * @exception MalformedURIException it authority is not a
1518    * well formed registry based authority
1519    */
1520   public void setRegBasedAuthority(String authority)
1521     throws MalformedURIException {
1522 
1523         if (authority == null) {
1524           m_regAuthority = null;
1525           return;
1526         }
1527         // reg_name = 1*( unreserved | escaped | "$" | "," |
1528         //            ";" | ":" | "@" | "&" | "=" | "+" )
1529         else if (authority.length() < 1 ||
1530           !isValidRegistryBasedAuthority(authority) ||
1531           authority.indexOf('/') != -1) {
1532       throw new MalformedURIException("Registry based authority is not well formed.");
1533         }
1534         m_regAuthority = authority;
1535         m_host = null;
1536         m_userinfo = null;
1537         m_port = -1;
1538   }
1539 
1540  /**
1541   * Set the path for this URI. If the supplied path is null, then the
1542   * query string and fragment are set to null as well. If the supplied
1543   * path includes a query string and/or fragment, these fields will be
1544   * parsed and set as well. Note that, for URIs following the "generic
1545   * URI" syntax, the path specified should start with a slash.
1546   * For URIs that do not follow the generic URI syntax, this method
1547   * sets the scheme-specific part.
1548   *
1549   * @param p_path the path for this URI (may be null)
1550   *
1551   * @exception MalformedURIException if p_path contains invalid
1552   *                                  characters
1553   */
1554   public void setPath(String p_path) throws MalformedURIException {
1555     if (p_path == null) {
1556       m_path = null;
1557       m_queryString = null;
1558       m_fragment = null;
1559     }
1560     else {
1561       initializePath(p_path, 0);
1562     }
1563   }
1564 
1565  /**
1566   * Append to the end of the path of this URI. If the current path does
1567   * not end in a slash and the path to be appended does not begin with
1568   * a slash, a slash will be appended to the current path before the
1569   * new segment is added. Also, if the current path ends in a slash
1570   * and the new segment begins with a slash, the extra slash will be
1571   * removed before the new segment is appended.
1572   *
1573   * @param p_addToPath the new segment to be added to the current path
1574   *
1575   * @exception MalformedURIException if p_addToPath contains syntax
1576   *                                  errors
1577   */
1578   public void appendPath(String p_addToPath)
1579                          throws MalformedURIException {
1580     if (p_addToPath == null || p_addToPath.trim().length() == 0) {
1581       return;
1582     }
1583 
1584     if (!isURIString(p_addToPath)) {
1585       throw new MalformedURIException(
1586               "Path contains invalid character!");
1587     }
1588 
1589     if (m_path == null || m_path.trim().length() == 0) {
1590       if (p_addToPath.startsWith("/")) {
1591         m_path = p_addToPath;
1592       }
1593       else {
1594         m_path = "/" + p_addToPath;
1595       }
1596     }
1597     else if (m_path.endsWith("/")) {
1598       if (p_addToPath.startsWith("/")) {
1599         m_path = m_path.concat(p_addToPath.substring(1));
1600       }
1601       else {
1602         m_path = m_path.concat(p_addToPath);
1603       }
1604     }
1605     else {
1606       if (p_addToPath.startsWith("/")) {
1607         m_path = m_path.concat(p_addToPath);
1608       }
1609       else {
1610         m_path = m_path.concat("/" + p_addToPath);
1611       }
1612     }
1613   }
1614 
1615  /**
1616   * Set the query string for this URI. A non-null value is valid only
1617   * if this is an URI conforming to the generic URI syntax and
1618   * the path value is not null.
1619   *
1620   * @param p_queryString the query string for this URI
1621   *
1622   * @exception MalformedURIException if p_queryString is not null and this
1623   *                                  URI does not conform to the generic
1624   *                                  URI syntax or if the path is null
1625   */
1626   public void setQueryString(String p_queryString) throws MalformedURIException {
1627     if (p_queryString == null) {
1628       m_queryString = null;
1629     }
1630     else if (!isGenericURI()) {
1631       throw new MalformedURIException(
1632               "Query string can only be set for a generic URI!");
1633     }
1634     else if (getPath() == null) {
1635       throw new MalformedURIException(
1636               "Query string cannot be set when path is null!");
1637     }
1638     else if (!isURIString(p_queryString)) {
1639       throw new MalformedURIException(
1640               "Query string contains invalid character!");
1641     }
1642     else {
1643       m_queryString = p_queryString;
1644     }
1645   }
1646 
1647  /**
1648   * Set the fragment for this URI. A non-null value is valid only
1649   * if this is a URI conforming to the generic URI syntax and
1650   * the path value is not null.
1651   *
1652   * @param p_fragment the fragment for this URI
1653   *
1654   * @exception MalformedURIException if p_fragment is not null and this
1655   *                                  URI does not conform to the generic
1656   *                                  URI syntax or if the path is null
1657   */
1658   public void setFragment(String p_fragment) throws MalformedURIException {
1659     if (p_fragment == null) {
1660       m_fragment = null;
1661     }
1662     else if (!isGenericURI()) {
1663       throw new MalformedURIException(
1664          "Fragment can only be set for a generic URI!");
1665     }
1666     else if (getPath() == null) {
1667       throw new MalformedURIException(
1668               "Fragment cannot be set when path is null!");
1669     }
1670     else if (!isURIString(p_fragment)) {
1671       throw new MalformedURIException(
1672               "Fragment contains invalid character!");
1673     }
1674     else {
1675       m_fragment = p_fragment;
1676     }
1677   }
1678 
1679  /**
1680   * Determines if the passed-in Object is equivalent to this URI.
1681   *
1682   * @param p_test the Object to test for equality.
1683   *
1684   * @return true if p_test is a URI with all values equal to this
1685   *         URI, false otherwise
1686   */
1687   @Override
1688   public boolean equals(Object p_test) {
1689     if (p_test instanceof URI) {
1690       URI testURI = (URI) p_test;
1691       if (((m_scheme == null && testURI.m_scheme == null) ||
1692            (m_scheme != null && testURI.m_scheme != null &&
1693             m_scheme.equals(testURI.m_scheme))) &&
1694           ((m_userinfo == null && testURI.m_userinfo == null) ||
1695            (m_userinfo != null && testURI.m_userinfo != null &&
1696             m_userinfo.equals(testURI.m_userinfo))) &&
1697           ((m_host == null && testURI.m_host == null) ||
1698            (m_host != null && testURI.m_host != null &&
1699             m_host.equals(testURI.m_host))) &&
1700             m_port == testURI.m_port &&
1701           ((m_path == null && testURI.m_path == null) ||
1702            (m_path != null && testURI.m_path != null &&
1703             m_path.equals(testURI.m_path))) &&
1704           ((m_queryString == null && testURI.m_queryString == null) ||
1705            (m_queryString != null && testURI.m_queryString != null &&
1706             m_queryString.equals(testURI.m_queryString))) &&
1707           ((m_fragment == null && testURI.m_fragment == null) ||
1708            (m_fragment != null && testURI.m_fragment != null &&
1709             m_fragment.equals(testURI.m_fragment)))) {
1710         return true;
1711       }
1712     }
1713     return false;
1714   }
1715 
1716     @Override
1717     public int hashCode() {
1718         int hash = 5;
1719         hash = 47 * hash + Objects.hashCode(this.m_scheme);
1720         hash = 47 * hash + Objects.hashCode(this.m_userinfo);
1721         hash = 47 * hash + Objects.hashCode(this.m_host);
1722         hash = 47 * hash + this.m_port;
1723         hash = 47 * hash + Objects.hashCode(this.m_path);
1724         hash = 47 * hash + Objects.hashCode(this.m_queryString);
1725         hash = 47 * hash + Objects.hashCode(this.m_fragment);
1726         return hash;
1727     }
1728 
1729  /**
1730   * Get the URI as a string specification. See RFC 2396 Section 5.2.
1731   *
1732   * @return the URI string specification
1733   */
1734   @Override
1735   public String toString() {
1736     final StringBuilder uriSpecString = new StringBuilder();
1737 
1738     if (m_scheme != null) {
1739       uriSpecString.append(m_scheme);
1740       uriSpecString.append(':');
1741     }
1742     uriSpecString.append(getSchemeSpecificPart());
1743     return uriSpecString.toString();
1744   }
1745 
1746  /**
1747   * Get the indicator as to whether this URI uses the "generic URI"
1748   * syntax.
1749   *
1750   * @return true if this URI uses the "generic URI" syntax, false
1751   *         otherwise
1752   */
1753   public boolean isGenericURI() {
1754     // presence of the host (whether valid or empty) means
1755     // double-slashes which means generic uri
1756     return (m_host != null);
1757   }
1758 
1759   /**
1760    * Returns whether this URI represents an absolute URI.
1761    *
1762    * @return true if this URI represents an absolute URI, false
1763    *         otherwise
1764    */
1765   public boolean isAbsoluteURI() {
1766       // presence of the scheme means absolute uri
1767       return (m_scheme != null);
1768   }
1769 
1770  /**
1771   * Determine whether a scheme conforms to the rules for a scheme name.
1772   * A scheme is conformant if it starts with an alphanumeric, and
1773   * contains only alphanumerics, '+','-' and '.'.
1774   *
1775   * @return true if the scheme is conformant, false otherwise
1776   */
1777   public static boolean isConformantSchemeName(String p_scheme) {
1778     if (p_scheme == null || p_scheme.trim().length() == 0) {
1779       return false;
1780     }
1781 
1782     if (!isAlpha(p_scheme.charAt(0))) {
1783       return false;
1784     }
1785 
1786     char testChar;
1787     int schemeLength = p_scheme.length();
1788     for (int i = 1; i < schemeLength; ++i) {
1789       testChar = p_scheme.charAt(i);
1790       if (!isSchemeCharacter(testChar)) {
1791         return false;
1792       }
1793     }
1794 
1795     return true;
1796   }
1797 
1798  /**
1799   * Determine whether a string is syntactically capable of representing
1800   * a valid IPv4 address, IPv6 reference or the domain name of a network host.
1801   * A valid IPv4 address consists of four decimal digit groups separated by a
1802   * '.'. Each group must consist of one to three digits. See RFC 2732 Section 3,
1803   * and RFC 2373 Section 2.2, for the definition of IPv6 references. A hostname
1804   * consists of domain labels (each of which must begin and end with an alphanumeric
1805   * but may contain '-') separated & by a '.'. See RFC 2396 Section 3.2.2.
1806   *
1807   * @return true if the string is a syntactically valid IPv4 address,
1808   * IPv6 reference or hostname
1809   */
1810   public static boolean isWellFormedAddress(String address) {
1811     if (address == null) {
1812       return false;
1813     }
1814 
1815     int addrLength = address.length();
1816     if (addrLength == 0) {
1817       return false;
1818     }
1819 
1820     // Check if the host is a valid IPv6reference.
1821     if (address.startsWith("[")) {
1822       return isWellFormedIPv6Reference(address);
1823     }
1824 
1825     // Cannot start with a '.', '-', or end with a '-'.
1826     if (address.startsWith(".") ||
1827         address.startsWith("-") ||
1828         address.endsWith("-")) {
1829       return false;
1830     }
1831 
1832     // rightmost domain label starting with digit indicates IP address
1833     // since top level domain label can only start with an alpha
1834     // see RFC 2396 Section 3.2.2
1835     int index = address.lastIndexOf('.');
1836     if (address.endsWith(".")) {
1837       index = address.substring(0, index).lastIndexOf('.');
1838     }
1839 
1840     if (index+1 < addrLength && isDigit(address.charAt(index+1))) {
1841       return isWellFormedIPv4Address(address);
1842     }
1843     else {
1844       // hostname      = *( domainlabel "." ) toplabel [ "." ]
1845       // domainlabel   = alphanum | alphanum *( alphanum | "-" ) alphanum
1846       // toplabel      = alpha | alpha *( alphanum | "-" ) alphanum
1847 
1848       // RFC 2396 states that hostnames take the form described in
1849       // RFC 1034 (Section 3) and RFC 1123 (Section 2.1). According
1850       // to RFC 1034, hostnames are limited to 255 characters.
1851       if (addrLength > 255) {
1852         return false;
1853       }
1854 
1855       // domain labels can contain alphanumerics and '-"
1856       // but must start and end with an alphanumeric
1857       char testChar;
1858       int labelCharCount = 0;
1859 
1860       for (int i = 0; i < addrLength; i++) {
1861         testChar = address.charAt(i);
1862         if (testChar == '.') {
1863           if (!isAlphanum(address.charAt(i-1))) {
1864             return false;
1865           }
1866           if (i+1 < addrLength && !isAlphanum(address.charAt(i+1))) {
1867             return false;
1868           }
1869           labelCharCount = 0;
1870         }
1871         else if (!isAlphanum(testChar) && testChar != '-') {
1872           return false;
1873         }
1874         // RFC 1034: Labels must be 63 characters or less.
1875         else if (++labelCharCount > 63) {
1876           return false;
1877         }
1878       }
1879     }
1880     return true;
1881   }
1882 
1883   /**
1884    * <p>Determines whether a string is an IPv4 address as defined by
1885    * RFC 2373, and under the further constraint that it must be a 32-bit
1886    * address. Though not expressed in the grammar, in order to satisfy
1887    * the 32-bit address constraint, each segment of the address cannot
1888    * be greater than 255 (8 bits of information).</p>
1889    *
1890    * <p><code>IPv4address = 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT</code></p>
1891    *
1892    * @return true if the string is a syntactically valid IPv4 address
1893    */
1894   public static boolean isWellFormedIPv4Address(String address) {
1895 
1896       int addrLength = address.length();
1897       char testChar;
1898       int numDots = 0;
1899       int numDigits = 0;
1900 
1901       // make sure that 1) we see only digits and dot separators, 2) that
1902       // any dot separator is preceded and followed by a digit and
1903       // 3) that we find 3 dots
1904       //
1905       // RFC 2732 amended RFC 2396 by replacing the definition
1906       // of IPv4address with the one defined by RFC 2373. - mrglavas
1907       //
1908       // IPv4address = 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT "." 1*3DIGIT
1909       //
1910       // One to three digits must be in each segment.
1911       for (int i = 0; i < addrLength; i++) {
1912         testChar = address.charAt(i);
1913         if (testChar == '.') {
1914           if ((i > 0 && !isDigit(address.charAt(i-1))) ||
1915               (i+1 < addrLength && !isDigit(address.charAt(i+1)))) {
1916             return false;
1917           }
1918           numDigits = 0;
1919           if (++numDots > 3) {
1920             return false;
1921           }
1922         }
1923         else if (!isDigit(testChar)) {
1924           return false;
1925         }
1926         // Check that that there are no more than three digits
1927         // in this segment.
1928         else if (++numDigits > 3) {
1929           return false;
1930         }
1931         // Check that this segment is not greater than 255.
1932         else if (numDigits == 3) {
1933           char first = address.charAt(i-2);
1934           char second = address.charAt(i-1);
1935           if (!(first < '2' ||
1936                (first == '2' &&
1937                (second < '5' ||
1938                (second == '5' && testChar <= '5'))))) {
1939             return false;
1940           }
1941         }
1942       }
1943       return (numDots == 3);
1944   }
1945 
1946   /**
1947    * <p>Determines whether a string is an IPv6 reference as defined
1948    * by RFC 2732, where IPv6address is defined in RFC 2373. The
1949    * IPv6 address is parsed according to Section 2.2 of RFC 2373,
1950    * with the additional constraint that the address be composed of
1951    * 128 bits of information.</p>
1952    *
1953    * <p><code>IPv6reference = "[" IPv6address "]"</code></p>
1954    *
1955    * <p>Note: The BNF expressed in RFC 2373 Appendix B does not
1956    * accurately describe section 2.2, and was in fact removed from
1957    * RFC 3513, the successor of RFC 2373.</p>
1958    *
1959    * @return true if the string is a syntactically valid IPv6 reference
1960    */
1961   public static boolean isWellFormedIPv6Reference(String address) {
1962 
1963       int addrLength = address.length();
1964       int index = 1;
1965       int end = addrLength-1;
1966 
1967       // Check if string is a potential match for IPv6reference.
1968       if (!(addrLength > 2 && address.charAt(0) == '['
1969           && address.charAt(end) == ']')) {
1970           return false;
1971       }
1972 
1973       // Counter for the number of 16-bit sections read in the address.
1974       int [] counter = new int[1];
1975 
1976       // Scan hex sequence before possible '::' or IPv4 address.
1977       index = scanHexSequence(address, index, end, counter);
1978       if (index == -1) {
1979           return false;
1980       }
1981       // Address must contain 128-bits of information.
1982       else if (index == end) {
1983           return (counter[0] == 8);
1984       }
1985 
1986       if (index+1 < end && address.charAt(index) == ':') {
1987           if (address.charAt(index+1) == ':') {
1988               // '::' represents at least one 16-bit group of zeros.
1989               if (++counter[0] > 8) {
1990                   return false;
1991               }
1992               index += 2;
1993               // Trailing zeros will fill out the rest of the address.
1994               if (index == end) {
1995                  return true;
1996               }
1997           }
1998           // If the second character wasn't ':', in order to be valid,
1999           // the remainder of the string must match IPv4Address,
2000           // and we must have read exactly 6 16-bit groups.
2001           else {
2002               return (counter[0] == 6) &&
2003                   isWellFormedIPv4Address(address.substring(index+1, end));
2004           }
2005       }
2006       else {
2007           return false;
2008       }
2009 
2010       // 3. Scan hex sequence after '::'.
2011       int prevCount = counter[0];
2012       index = scanHexSequence(address, index, end, counter);
2013 
2014       // We've either reached the end of the string, the address ends in
2015       // an IPv4 address, or it is invalid. scanHexSequence has already
2016       // made sure that we have the right number of bits.
2017       return (index == end) ||
2018           (index != -1 && isWellFormedIPv4Address(
2019           address.substring((counter[0] > prevCount) ? index+1 : index, end)));
2020   }
2021 
2022   /**
2023    * Helper method for isWellFormedIPv6Reference which scans the
2024    * hex sequences of an IPv6 address. It returns the index of the
2025    * next character to scan in the address, or -1 if the string
2026    * cannot match a valid IPv6 address.
2027    *
2028    * @param address the string to be scanned
2029    * @param index the beginning index (inclusive)
2030    * @param end the ending index (exclusive)
2031    * @param counter a counter for the number of 16-bit sections read
2032    * in the address
2033    *
2034    * @return the index of the next character to scan, or -1 if the
2035    * string cannot match a valid IPv6 address
2036    */
2037   private static int scanHexSequence (String address, int index, int end, int [] counter) {
2038 
2039       char testChar;
2040       int numDigits = 0;
2041       int start = index;
2042 
2043       // Trying to match the following productions:
2044       // hexseq = hex4 *( ":" hex4)
2045       // hex4   = 1*4HEXDIG
2046       for (; index < end; ++index) {
2047         testChar = address.charAt(index);
2048         if (testChar == ':') {
2049             // IPv6 addresses are 128-bit, so there can be at most eight sections.
2050             if (numDigits > 0 && ++counter[0] > 8) {
2051                 return -1;
2052             }
2053             // This could be '::'.
2054             if (numDigits == 0 || ((index+1 < end) && address.charAt(index+1) == ':')) {
2055                 return index;
2056             }
2057             numDigits = 0;
2058         }
2059         // This might be invalid or an IPv4address. If it's potentially an IPv4address,
2060         // backup to just after the last valid character that matches hexseq.
2061         else if (!isHex(testChar)) {
2062             if (testChar == '.' && numDigits < 4 && numDigits > 0 && counter[0] <= 6) {
2063                 int back = index - numDigits - 1;
2064                 return (back >= start) ? back : (back+1);
2065             }
2066             return -1;
2067         }
2068         // There can be at most 4 hex digits per group.
2069         else if (++numDigits > 4) {
2070             return -1;
2071         }
2072       }
2073       return (numDigits > 0 && ++counter[0] <= 8) ? end : -1;
2074   }
2075 
2076 
2077  /**
2078   * Determine whether a char is a digit.
2079   *
2080   * @return true if the char is betweeen '0' and '9', false otherwise
2081   */
2082   private static boolean isDigit(char p_char) {
2083     return p_char >= '0' && p_char <= '9';
2084   }
2085 
2086  /**
2087   * Determine whether a character is a hexadecimal character.
2088   *
2089   * @return true if the char is betweeen '0' and '9', 'a' and 'f'
2090   *         or 'A' and 'F', false otherwise
2091   */
2092   private static boolean isHex(char p_char) {
2093     return (p_char <= 'f' && (fgLookupTable[p_char] & ASCII_HEX_CHARACTERS) != 0);
2094   }
2095 
2096  /**
2097   * Determine whether a char is an alphabetic character: a-z or A-Z
2098   *
2099   * @return true if the char is alphabetic, false otherwise
2100   */
2101   private static boolean isAlpha(char p_char) {
2102       return ((p_char >= 'a' && p_char <= 'z') || (p_char >= 'A' && p_char <= 'Z' ));
2103   }
2104 
2105  /**
2106   * Determine whether a char is an alphanumeric: 0-9, a-z or A-Z
2107   *
2108   * @return true if the char is alphanumeric, false otherwise
2109   */
2110   private static boolean isAlphanum(char p_char) {
2111      return (p_char <= 'z' && (fgLookupTable[p_char] & MASK_ALPHA_NUMERIC) != 0);
2112   }
2113 
2114  /**
2115   * Determine whether a character is a reserved character:
2116   * ';', '/', '?', ':', '@', '&', '=', '+', '$', ',', '[', or ']'
2117   *
2118   * @return true if the string contains any reserved characters
2119   */
2120   private static boolean isReservedCharacter(char p_char) {
2121      return (p_char <= ']' && (fgLookupTable[p_char] & RESERVED_CHARACTERS) != 0);
2122   }
2123 
2124  /**
2125   * Determine whether a char is an unreserved character.
2126   *
2127   * @return true if the char is unreserved, false otherwise
2128   */
2129   private static boolean isUnreservedCharacter(char p_char) {
2130      return (p_char <= '~' && (fgLookupTable[p_char] & MASK_UNRESERVED_MASK) != 0);
2131   }
2132 
2133  /**
2134   * Determine whether a char is a URI character (reserved or
2135   * unreserved, not including '%' for escaped octets).
2136   *
2137   * @return true if the char is a URI character, false otherwise
2138   */
2139   private static boolean isURICharacter (char p_char) {
2140       return (p_char <= '~' && (fgLookupTable[p_char] & MASK_URI_CHARACTER) != 0);
2141   }
2142 
2143  /**
2144   * Determine whether a char is a scheme character.
2145   *
2146   * @return true if the char is a scheme character, false otherwise
2147   */
2148   private static boolean isSchemeCharacter (char p_char) {
2149       return (p_char <= 'z' && (fgLookupTable[p_char] & MASK_SCHEME_CHARACTER) != 0);
2150   }
2151 
2152  /**
2153   * Determine whether a char is a userinfo character.
2154   *
2155   * @return true if the char is a userinfo character, false otherwise
2156   */
2157   private static boolean isUserinfoCharacter (char p_char) {
2158       return (p_char <= 'z' && (fgLookupTable[p_char] & MASK_USERINFO_CHARACTER) != 0);
2159   }
2160 
2161  /**
2162   * Determine whether a char is a path character.
2163   *
2164   * @return true if the char is a path character, false otherwise
2165   */
2166   private static boolean isPathCharacter (char p_char) {
2167       return (p_char <= '~' && (fgLookupTable[p_char] & MASK_PATH_CHARACTER) != 0);
2168   }
2169 
2170 
2171  /**
2172   * Determine whether a given string contains only URI characters (also
2173   * called "uric" in RFC 2396). uric consist of all reserved
2174   * characters, unreserved characters and escaped characters.
2175   *
2176   * @return true if the string is comprised of uric, false otherwise
2177   */
2178   private static boolean isURIString(String p_uric) {
2179     if (p_uric == null) {
2180       return false;
2181     }
2182     int end = p_uric.length();
2183     char testChar = '\0';
2184     for (int i = 0; i < end; i++) {
2185       testChar = p_uric.charAt(i);
2186       if (testChar == '%') {
2187         if (i+2 >= end ||
2188             !isHex(p_uric.charAt(i+1)) ||
2189             !isHex(p_uric.charAt(i+2))) {
2190           return false;
2191         }
2192         else {
2193           i += 2;
2194           continue;
2195         }
2196       }
2197       if (isURICharacter(testChar)) {
2198           continue;
2199       }
2200       else {
2201         return false;
2202       }
2203     }
2204     return true;
2205   }
2206 }