Source code: com/hp/hpl/jena/rdf/arp/URI.java

   /*
    * The Apache Software License, Version 1.1
    *
    *
    * Copyright (c) 1999,2001 The Apache Software Foundation.  All rights
    * reserved.
    *
    * Redistribution and use in source and binary forms, with or without
    * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. The end-user documentation included with the redistribution,
   *    if any, must include the following acknowledgment:
   *       "This product includes software developed by the
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowledgment may appear in the software itself,
   *    if and wherever such third-party acknowledgments normally appear.
   *
   * 4. The names "Xerces" and "Apache Software Foundation" must
   *    not be used to endorse or promote products derived from this
   *    software without prior written permission. For written
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache",
   *    nor may "Apache" appear in their name, without prior written
   *    permission of the Apache Software Foundation.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
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   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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   * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation and was
   * originally based on software copyright (c) 1999, iClick Inc.,
   * http://www.apache.org.  For more information on the Apache Software
   * Foundation, please see <http://www.apache.org/>.
   */
  
  /* Modified by Jeremy J. Carroll HP
   *
   * Was originally org/apache/xerces/utils/URI.java in Xerces 1.4.4
   *
   */
  
  package com.hp.hpl.jena.rdf.arp;
  
  import java.io.Serializable;
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  
  /**********************************************************************
  * A class to represent a Uniform Resource Identifier (URI). This class
  * is designed to handle the parsing of URIs and provide access to
  * the various components (scheme, host, port, userinfo, path, query
  * string and fragment) that may constitute a URI.
  * <p>
  * Parsing of a URI specification is done according to the URI
  * syntax described in RFC 2396
  * <http://www.ietf.org/rfc/rfc2396.txt?number=2396>. Every URI consists
  * of a scheme, followed by a colon (':'), followed by a scheme-specific
  * part. For URIs that follow the "generic URI" syntax, the scheme-
  * specific part begins with two slashes ("//") and may be followed
  * by an authority segment (comprised of user information, host, and
  * port), path segment, query segment and fragment. Note that RFC 2396
  * no longer specifies the use of the parameters segment and excludes
  * the "user:password" syntax as part of the authority segment. If
  * "user:password" appears in a URI, the entire user/password string
  * is stored as userinfo.
  * <p>
  * For URIs that do not follow the "generic URI" syntax (e.g. mailto),
  * the entire scheme-specific part is treated as the "path" portion
  * of the URI.
  * <p>
  * Note that, unlike the java.net.URL class, this class does not provide
  * any built-in network access functionality nor does it provide any
  * scheme-specific functionality (for example, it does not know a
  * default port for a specific scheme). Rather, it only knows the
  * grammar and basic set of operations that can be applied to a URI.
  *
  * @version  $Id: URI.java,v 1.17 2004/07/13 14:50:24 chris-dollin Exp $
 *
 **********************************************************************/
 public class URI implements Serializable {
   
   static Log logger = LogFactory.getLog(URI.class);
 
   /** reserved characters */
   private static final String RESERVED_CHARACTERS = ";/?:@&=+$,[]";
 
   /** URI punctuation mark characters - these, combined with
       alphanumerics, constitute the "unreserved" characters */
   private static final String MARK_CHARACTERS = "-_.!~*'() ";
 
   /** scheme can be composed of alphanumerics and these characters */
   private static final String SCHEME_CHARACTERS = "+-.";
 
   /** userinfo can be composed of unreserved, escaped and these
       characters */
   private static final String USERINFO_CHARACTERS = ";:&=+$,";
 
   /** Stores the scheme (usually the protocol) for this URI. */
   private String m_scheme = null;
 
   /** If specified, stores the userinfo for this URI; otherwise null */
   private String m_userinfo = null;
 
   /** If specified, stores the host for this URI; otherwise null */
   private String m_host = null;
 
   /** If specified, stores the port for this URI; otherwise null */
   private String m_port = null;
   private int n_port = -1;
 
   /** If specified, stores the path for this URI; otherwise null */
   private String m_path = null;
   /** Lazily assigned variable being: ??
      * { m_path +"a", dir, parent-dir, grand-parent-dir }
      * Each component is lazily assigned too.
    */
   private String m_subPaths[] = null;
 
   /** If specified, stores the query string for this URI; otherwise
       null.  */
   private String m_queryString = null;
 
   /** If specified, stores the fragment for this URI; otherwise null */
   private String m_fragment = null;
 
   private static boolean DEBUG = false;
 
   /**
   * Construct a new and uninitialized URI.
   */
   public URI() {
   }
 
   /**
    * Construct a new URI from another URI. All fields for this URI are
    * set equal to the fields of the URI passed in.
    *
    * @param p_other the URI to copy (cannot be null)
    */
   public URI(URI p_other) {
     initialize(p_other);
   }
 
   /**
    * Construct a new URI from a URI specification string. If the
    * specification follows the "generic URI" syntax, (two slashes
    * following the first colon), the specification will be parsed
    * accordingly - setting the scheme, userinfo, host,port, path, query
    * string and fragment fields as necessary. If the specification does
    * not follow the "generic URI" syntax, the specification is parsed
    * into a scheme and scheme-specific part (stored as the path) only.
    *
    * @param p_uriSpec the URI specification string (cannot be null or
    *                  empty)
    *
    * @exception MalformedURIException if p_uriSpec violates any syntax
    *                                   rules
    */
   public URI(String p_uriSpec) throws MalformedURIException {
     this((URI) null, p_uriSpec);
   }
 
   /**
    * Construct a new URI from a base URI and a URI specification string.
    * The URI specification string may be a relative URI.
    *
    * @param p_base the base URI (cannot be null if p_uriSpec is null or
    *               empty)
    * @param p_uriSpec the URI specification string (cannot be null or
    *                  empty if p_base is null)
    *
    * @exception MalformedURIException if p_uriSpec violates any syntax
    *                                  rules
    */
   public URI(URI p_base, String p_uriSpec) throws MalformedURIException {
     initialize(p_base, p_uriSpec);
   }
 
   /**
    * Construct a new URI that does not follow the generic URI syntax.
    * Only the scheme and scheme-specific part (stored as the path) are
    * initialized.
    *
    * @param p_scheme the URI scheme (cannot be null or empty)
    * @param p_schemeSpecificPart the scheme-specific part (cannot be
    *                             null or empty)
    *
    * @exception MalformedURIException if p_scheme violates any
    *                                  syntax rules
    */
   public URI(String p_scheme, String p_schemeSpecificPart)
     throws MalformedURIException {
     if (p_scheme == null || p_scheme.length() == 0) {
       throw new MalformedURIException("Cannot construct URI with null/empty scheme!");
     }
     if (p_schemeSpecificPart == null
       || p_schemeSpecificPart.length() == 0) {
       throw new MalformedURIException("Cannot construct URI with null/empty scheme-specific part!");
     }
     setScheme(p_scheme);
     setPath(p_schemeSpecificPart);
   }
 
   /**
    * Construct a new URI that follows the generic URI syntax from its
    * component parts. Each component is validated for syntax and some
    * basic semantic checks are performed as well.  See the individual
    * setter methods for specifics.
    *
    * @param p_scheme the URI scheme (cannot be null or empty)
    * @param p_host the hostname or IPv4 address for the URI
    * @param p_path the URI path - if the path contains '?' or '#',
    *               then the query string and/or fragment will be
    *               set from the path; however, if the query and
    *               fragment are specified both in the path and as
    *               separate parameters, an exception is thrown
    * @param p_queryString the URI query string (cannot be specified
    *                      if path is null)
    * @param p_fragment the URI fragment (cannot be specified if path
    *                   is null)
    *
    * @exception MalformedURIException if any of the parameters violates
    *                                  syntax rules or semantic rules
    */
   public URI(
     String p_scheme,
     String p_host,
     String p_path,
     String p_queryString,
     String p_fragment)
     throws MalformedURIException {
     this(p_scheme, null, p_host, -1, p_path, p_queryString, p_fragment);
   }
 
   /**
    * Construct a new URI that follows the generic URI syntax from its
    * component parts. Each component is validated for syntax and some
    * basic semantic checks are performed as well.  See the individual
    * setter methods for specifics.
    *
    * @param p_scheme the URI scheme (cannot be null or empty)
    * @param p_userinfo the URI userinfo (cannot be specified if host
    *                   is null)
    * @param p_host the hostname or IPv4 address for the URI
    * @param p_port the URI port (may be -1 for "unspecified"; cannot
    *               be specified if host is null)
    * @param p_path the URI path - if the path contains '?' or '#',
    *               then the query string and/or fragment will be
    *               set from the path; however, if the query and
    *               fragment are specified both in the path and as
    *               separate parameters, an exception is thrown
    * @param p_queryString the URI query string (cannot be specified
    *                      if path is null)
    * @param p_fragment the URI fragment (cannot be specified if path
    *                   is null)
    *
    * @exception MalformedURIException if any of the parameters violates
    *                                  syntax rules or semantic rules
    */
   public URI(
     String p_scheme,
     String p_userinfo,
     String p_host,
     int p_port,
     String p_path,
     String p_queryString,
     String p_fragment)
     throws MalformedURIException {
     if (p_scheme == null || p_scheme.length() == 0) {
       throw new MalformedURIException("Scheme is required!");
     }
 
     if (p_host == null) {
       if (p_userinfo != null) {
         throw new MalformedURIException("Userinfo may not be specified if host is not specified!");
       }
       if (p_port != -1) {
         throw new MalformedURIException("Port may not be specified if host is not specified!");
       }
     }
 
     if (p_path != null) {
       if (p_path.indexOf('?') != -1 && p_queryString != null) {
         throw new MalformedURIException("Query string cannot be specified in path and query string!");
       }
 
       if (p_path.indexOf('#') != -1 && p_fragment != null) {
         throw new MalformedURIException("Fragment cannot be specified in both the path and fragment!");
       }
     }
 
     setScheme(p_scheme);
     setHost(p_host);
     setPort(p_port);
     m_port = "" + p_port;
     setUserinfo(p_userinfo);
     setPath(p_path);
     setQueryString(p_queryString);
     setFragment(p_fragment);
   }
 
   /**
    * Initialize all fields of this URI from another URI.
    *
    * @param p_other the URI to copy (cannot be null)
    */
   private void initialize(URI p_other) {
     m_scheme = p_other.getScheme();
     m_userinfo = p_other.getUserinfo();
     m_host = p_other.getHost();
     m_port = p_other.m_port;
     n_port = p_other.n_port;
     m_path = p_other.getPath();
     m_queryString = p_other.getQueryString();
     m_fragment = p_other.getFragment();
   }
 
   /**
    * Initializes this URI from a base URI and a URI specification string.
    * See RFC 2396 Section 4 and Appendix B for specifications on parsing
    * the URI and Section 5 for specifications on resolving relative URIs
    * and relative paths.
    *
    * @param p_base the base URI (may be null if p_uriSpec is an absolute
    *               URI)
    * @param p_uriSpec the URI spec string which may be an absolute or
    *                  relative URI (can only be null/empty if p_base
    *                  is not null)
    *
    * @exception MalformedURIException if p_base is null and p_uriSpec
    *                                  is not an absolute URI or if
    *                                  p_uriSpec violates syntax rules
    */
   private void initialize(URI p_base, String p_uriSpec)
     throws MalformedURIException {
     if (p_base == null && (p_uriSpec == null || p_uriSpec.length() == 0)) {
       throw new RelativeURIException("Cannot initialize URI with empty parameters.");
     }
 
     // just make a copy of the base if spec is empty
     if (p_uriSpec == null || p_uriSpec.length() == 0) {
       initialize(p_base);
       return;
     }
 
     String uriSpec = p_uriSpec;
     int uriSpecLen = uriSpec.length();
     int index = 0;
 
     // Check for scheme, which must be before '/', '?' or '#'. Also handle
     // names with DOS drive letters ('D:'), so 1-character schemes are not
     // allowed.
     int colonIdx = uriSpec.indexOf(':');
     int slashIdx = uriSpec.indexOf('/');
     int queryIdx = uriSpec.indexOf('?');
     int fragmentIdx = uriSpec.indexOf('#');
 
     if ((colonIdx < 2)
       || (colonIdx > slashIdx && slashIdx != -1)
       || (colonIdx > queryIdx && queryIdx != -1)
       || (colonIdx > fragmentIdx && fragmentIdx != -1)) {
       // We need to do the relative URI algorithm:
 
       // jjc: the spec says:
       // 'URI-reference = [ absoluteURI | relativeURI ] [ "#" fragment ]'
       // My understanding is that if there is only the fragment
       // then this is a relative URI.
       if (p_base == null // del jjc: && fragmentIdx != 0
       ) {
         // Nothing to be relative against.
         throw new RelativeURIException("No scheme found in URI '" + p_uriSpec + "'" );
       } else {
         if ((!p_base.isGenericURI()) && fragmentIdx != 0)
           // Can't be relative against opaque URI (except using the #frag).
           throw new MalformedURIException("Cannot apply relative URI to an opaque URI");
       }
     } else {
       initializeScheme(uriSpec);
       index = m_scheme.length() + 1;
     }
 
     // two slashes means generic URI syntax, so we get the authority
     if (((index + 1) < uriSpecLen)
       && (uriSpec.substring(index).startsWith("//"))) {
       index += 2;
       int startPos = index;
 
       // get authority - everything up to path, query or fragment
       char testChar = '\0';
       while (index < uriSpecLen) {
         testChar = uriSpec.charAt(index);
         if (testChar == '/' || testChar == '?' || testChar == '#') {
           break;
         }
         index++;
       }
 
       // if we found authority, parse it out, otherwise we set the
       // host to empty string
       if (index > startPos) {
         initializeAuthority(uriSpec.substring(startPos, index));
       } else {
         m_host = "";
       }
     }
 
     initializePath(uriSpec.substring(index));
 
     // Resolve relative URI to base URI - see RFC 2396 Section 5.2
     // In some cases, it might make more sense to throw an exception
     // (when scheme is specified is the string spec and the base URI
     // is also specified, for example), but we're just following the
     // RFC specifications
     if (p_base != null) {
 
       // check to see if this is the current doc - RFC 2396 5.2 #2
       // note that this is slightly different from the RFC spec in that
       // we don't include the check for query string being null
       // - this handles cases where the urispec is just a query
       // string or a fragment (e.g. "?y" or "#s") -
       // see <http://www.ics.uci.edu/~fielding/url/test1.html> which
       // identified this as a bug in the RFC
       if (m_path.length() == 0 && m_scheme == null && m_host == null) {
         m_scheme = p_base.getScheme();
         m_userinfo = p_base.getUserinfo();
         m_host = p_base.getHost();
         m_port = p_base.m_port;
         n_port = p_base.getPort();
         m_path = p_base.getPath();
 
         if (m_queryString == null) {
           m_queryString = p_base.getQueryString();
         }
         return;
       }
 
       // check for scheme - RFC 2396 5.2 #3
       // if we found a scheme, it means absolute URI, so we're done
       if (m_scheme == null) {
         m_scheme = p_base.getScheme();
       } else {
         return;
       }
 
       // check for authority - RFC 2396 5.2 #4
       // if we found a host, then we've got a network path, so we're done
       if (m_host == null) {
         m_userinfo = p_base.getUserinfo();
         m_host = p_base.getHost();
         m_port = p_base.m_port;
         n_port = p_base.getPort();
       } else {
         return;
       }
 
       // check for absolute path - RFC 2396 5.2 #5
       if (m_path.length() > 0 && m_path.startsWith("/")) {
         return;
       }
 
       // if we get to this point, we need to resolve relative path
       // RFC 2396 5.2 #6
         String path = // jjc new String();
   "/"; // jjc ins
       String basePath = p_base.getPath();
 
       // 6a - get all but the last segment of the base URI path
       if (basePath != null) {
         int lastSlash = basePath.lastIndexOf('/');
         if (lastSlash != -1) {
           path = basePath.substring(0, lastSlash + 1);
         }
       }
 
       // 6b - append the relative URI path
       path = path.concat(m_path);
 
       // 6c - remove all "./" where "." is a complete path segment
       index = -1;
       while ((index = path.indexOf("/./")) != -1) {
         path =
           path.substring(0, index + 1).concat(
             path.substring(index + 3));
       }
 
       // 6d - remove "." if path ends with "." as a complete path segment
       if (path.endsWith("/.")) {
         path = path.substring(0, path.length() - 1);
       }
 
       // 6e - remove all "<segment>/../" where "<segment>" is a complete
       // path segment not equal to ".."
       index = 1;
       int segIndex = -1;
 
       while ((index = path.indexOf("/../", index)) > 0) {
         segIndex = path.lastIndexOf('/', index - 1);
         if (segIndex != -1
           && !path.substring(segIndex + 1, index).equals("..")) {
           path =
             path.substring(0, segIndex).concat(
               path.substring(index + 3));
           index = segIndex;
         } else {
           index += 4;
         }
       }
 
       // 6f - remove ending "<segment>/.." where "<segment>" is a
       // complete path segment
       if (path.endsWith("/..")) {
         index = path.length() - 3;
         segIndex = path.lastIndexOf('/', index - 1);
         if (segIndex != -1
           && !path.substring(segIndex + 1, index).equals("..")) {
           path = path.substring(0, segIndex + 1);
         }
       }
 
       m_path = path;
     }
   }
 
   /**
    * Initialize the scheme for this URI from a URI string spec.
    *
    * @param p_uriSpec the URI specification (cannot be null)
    *
    * @exception MalformedURIException if URI does not have a conformant
    *                                  scheme
    */
   private void initializeScheme(String p_uriSpec)
     throws MalformedURIException {
     int uriSpecLen = p_uriSpec.length();
     int index = p_uriSpec.indexOf(':');
 
     if (index < 1)
       throw new MalformedURIException("No scheme found in URI '" + p_uriSpec + "'" );
 
     if (index == uriSpecLen - 1)
       throw new MalformedURIException( "A bare scheme name is not a URI: '" +  p_uriSpec + "'" );
 
     setScheme(p_uriSpec.substring(0, index));
   }
 
   /**
    * Initialize the authority (userinfo, host and port) for this
    * URI from a URI string spec.
    *
    * @param p_uriSpec the URI specification (cannot be null)
    *
    * @exception MalformedURIException if p_uriSpec violates syntax rules
    */
   private void initializeAuthority(String p_uriSpec)
     throws MalformedURIException {
     int index = 0;
     int start = 0;
     int end = p_uriSpec.length();
     char testChar = '\0';
     String userinfo = null;
 
     // userinfo is everything up @
     if (p_uriSpec.indexOf('@', start) != -1) {
       while (index < end) {
         testChar = p_uriSpec.charAt(index);
         if (testChar == '@') {
           break;
         }
         index++;
       }
       userinfo = p_uriSpec.substring(start, index);
       index++;
     }
 
     // host is everything up to ':'
     String host = null;
     start = index;
     while (index < end) {
       testChar = p_uriSpec.charAt(index);
       if (testChar == ':') {
         break;
       }
       index++;
     }
     host = p_uriSpec.substring(start, index);
     int port = -1;
     if (host.length() > 0) {
       // port
       if (testChar == ':') {
         index++;
         start = index;
         while (index < end) {
           index++;
         }
         String portStr = p_uriSpec.substring(start, index);
         if (portStr.length() > 0) {
           for (int i = 0; i < portStr.length(); i++) {
             if (!isDigit(portStr.charAt(i))) {
               throw new MalformedURIException(
                 portStr
                   + " is invalid. Port should only contain digits!");
             }
           }
           try {
             port = Integer.parseInt(portStr);
             m_port = portStr;
           } catch (NumberFormatException nfe) {
             // can't happen
           }
         }
       }
     }
     setHost(host);
     setPort(port);
     setUserinfo(userinfo);
   }
 
   /**
    * Initialize the path for this URI from a URI string spec.
    *
    * @param p_uriSpec the URI specification (cannot be null)
    *
    * @exception MalformedURIException if p_uriSpec violates syntax rules
    */
   private void initializePath(String p_uriSpec)
     throws MalformedURIException {
     if (p_uriSpec == null) {
       throw new MalformedURIException("Cannot initialize path from null string!");
     }
 
     int index = 0;
     int start = 0;
     int end = p_uriSpec.length();
     char testChar = '\0';
 
     // path - everything up to query string or fragment
     while (index < end) {
       testChar = p_uriSpec.charAt(index);
       if (testChar == '?' || testChar == '#') {
         break;
       }
       // check for valid escape sequence
       if (testChar == '%') {
         if (index + 2 >= end
           || !isHex(p_uriSpec.charAt(index + 1))
           || !isHex(p_uriSpec.charAt(index + 2))) {
           throw new MalformedURIException( "Path contains invalid escape sequence: " + p_uriSpec );
         }
       } else if (
         !isReservedCharacter(testChar)
           && !isUnreservedCharacter(testChar)) {
         throw new MalformedURIException(
           "Path '" + p_uriSpec + "' contains invalid character: " + testChar);
       }
       index++;
     }
     m_path = p_uriSpec.substring(start, index);
 
     // query - starts with ? and up to fragment or end
     if (testChar == '?') {
       index++;
       start = index;
       while (index < end) {
         testChar = p_uriSpec.charAt(index);
         if (testChar == '#') {
           break;
         }
         if (testChar == '%') {
           if (index + 2 >= end
             || !isHex(p_uriSpec.charAt(index + 1))
             || !isHex(p_uriSpec.charAt(index + 2))) {
             throw new MalformedURIException("Query string contains invalid escape sequence in '" + p_uriSpec + "'" );
           }
         } else if (
           !isReservedCharacter(testChar)
             && !isUnreservedCharacter(testChar)) {
           throw new MalformedURIException( "Query string contains invalid character '" + testChar + "' in '" + p_uriSpec + "'" );
         }
         index++;
       }
       m_queryString = p_uriSpec.substring(start, index);
     }
 
     // fragment - starts with #
     if (testChar == '#') {
       index++;
       start = index;
       while (index < end) {
         testChar = p_uriSpec.charAt(index);
 
         if (testChar == '%') {
           if (index + 2 >= end
             || !isHex(p_uriSpec.charAt(index + 1))
             || !isHex(p_uriSpec.charAt(index + 2))) {
             throw new MalformedURIException( "Fragment contains invalid escape sequence in '" + p_uriSpec + "'" );
           }
         } else if (
           !isReservedCharacter(testChar)
             && !isUnreservedCharacter(testChar)) {
           throw new MalformedURIException(
             "Fragment contains invalid character '" + testChar + "' in '" + p_uriSpec + "'" );
         }
         index++;
       }
       m_fragment = p_uriSpec.substring(start, index);
     }
   }
 
   /**
    * Get the scheme for this URI.
    *
    * @return the scheme for this URI
    */
   public String getScheme() {
     return m_scheme;
   }
 
   /**
    * Get the scheme-specific part for this URI (everything following the
    * scheme and the first colon). See RFC 2396 Section 5.2 for spec.
    *
    * @return the scheme-specific part for this URI
    */
   public String getSchemeSpecificPart() {
     StringBuffer schemespec = new StringBuffer();
 
     if (m_userinfo != null || m_host != null || m_port != null) {
       schemespec.append("//");
     }
 
     if (m_userinfo != null) {
       schemespec.append(m_userinfo);
       schemespec.append('@');
     }
 
     if (m_host != null) {
       schemespec.append(m_host);
     }
 
     if (m_port != null) {
       schemespec.append(':');
       schemespec.append(m_port);
     }
 
     if (m_path != null) {
       schemespec.append((m_path));
     }
 
     if (m_queryString != null) {
       schemespec.append('?');
       schemespec.append(m_queryString);
     }
 
     if (m_fragment != null) {
       schemespec.append('#');
       schemespec.append(m_fragment);
     }
 
     return schemespec.toString();
   }
 
   /**
    * Get the userinfo for this URI.
    *
    * @return the userinfo for this URI (null if not specified).
    */
   public String getUserinfo() {
     return m_userinfo;
   }
 
   /**
   * Get the host for this URI.
   *
   * @return the host for this URI (null if not specified).
   */
   public String getHost() {
     return m_host;
   }
 
   /**
    * Get the port for this URI.
    *
    * @return the port for this URI (-1 if not specified).
    */
   public int getPort() {
     return n_port;
   }
 
   /**
    * Get the path for this URI (optionally with the query string and
    * fragment).
    *
    * @param p_includeQueryString if true (and query string is not null),
    *                             then a "?" followed by the query string
    *                             will be appended
    * @param p_includeFragment if true (and fragment is not null),
    *                             then a "#" followed by the fragment
    *                             will be appended
    *
    * @return the path for this URI possibly including the query string
    *         and fragment
    */
   public String getPath(
     boolean p_includeQueryString,
     boolean p_includeFragment) {
     StringBuffer pathString = new StringBuffer(m_path);
 
     if (p_includeQueryString && m_queryString != null) {
       pathString.append('?');
       pathString.append(m_queryString);
     }
 
     if (p_includeFragment && m_fragment != null) {
       pathString.append('#');
       pathString.append(m_fragment);
     }
     return pathString.toString();
   }
 
   /**
    * Get the path for this URI. Note that the value returned is the path
    * only and does not include the query string or fragment.
    *
    * @return the path for this URI.
    */
   public String getPath() {
     return m_path;
   }
 
   /**
    * Get the query string for this URI.
    *
    * @return the query string for this URI. Null is returned if there
    *         was no "?" in the URI spec, empty string if there was a
    *         "?" but no query string following it.
    */
   public String getQueryString() {
     return m_queryString;
   }
 
   /**
    * Get the fragment for this URI.
    *
    * @return the fragment for this URI. Null is returned if there
    *         was no "#" in the URI spec, empty string if there was a
    *         "#" but no fragment following it.
    */
   public String getFragment() {
     return m_fragment;
   }
 
   /**
    * Set the scheme for this URI. The scheme is converted to lowercase
    * before it is set.
    *
    * @param p_scheme the scheme for this URI (cannot be null)
    *
    * @exception MalformedURIException if p_scheme is not a conformant
    *                                  scheme name
    */
   private void setScheme(String p_scheme) throws MalformedURIException {
     if (p_scheme == null) {
       throw new MalformedURIException("Cannot set scheme from null string!");
     }
     if (!isConformantSchemeName(p_scheme)) {
       throw new MalformedURIException("The scheme '" + p_scheme + "' is not conformant.");
     }
 
     m_scheme = p_scheme; //.toLowerCase();
   }
 
   /**
    * Set the userinfo for this URI. If a non-null value is passed in and
    * the host value is null, then an exception is thrown.
    *
    * @param p_userinfo the userinfo for this URI
    *
    * @exception MalformedURIException if p_userinfo contains invalid
    *                                  characters
    */
   private void setUserinfo(String p_userinfo) throws MalformedURIException {
     if (p_userinfo == null) {
       m_userinfo = null;
     } else {
       if (m_host == null) {
         throw new MalformedURIException("Userinfo cannot be set when host is null!");
       }
 
       // userinfo can contain alphanumerics, mark characters, escaped
       // and ';',':','&','=','+','$',','
       int index = 0;
       int end = p_userinfo.length();
       char testChar = '\0';
       while (index < end) {
         testChar = p_userinfo.charAt(index);
         if (testChar == '%') {
           if (index + 2 >= end
             || !isHex(p_userinfo.charAt(index + 1))
             || !isHex(p_userinfo.charAt(index + 2))) {
             throw new MalformedURIException("Userinfo contains invalid escape sequence!");
           }
         } else if (
           !isUnreservedCharacter(testChar)
             && USERINFO_CHARACTERS.indexOf(testChar) == -1) {
           throw new MalformedURIException(
             "Userinfo contains invalid character:" + testChar);
         }
         index++;
       }
     }
     m_userinfo = p_userinfo;
   }
 
   /**
   * Set the host for this URI. If null is passed in, the userinfo
   * field is also set to null and the port is set to -1.
   *
   * @param p_host the host for this URI
   *
   * @exception MalformedURIException if p_host is not a valid IP
   *                                  address or DNS hostname.
   */
   private void setHost(String p_host) throws MalformedURIException {
     if (p_host == null || p_host.length() == 0) {
       m_host = p_host;
       m_userinfo = null;
       m_port = null;
       n_port = -1;
     } else if (!isWellFormedAddress(p_host)) {
       throw new MalformedURIException( "Host is not a well formed address in '" + p_host + "'" );
     }
     m_host = p_host;
   }
 
   /**
    * Set the port for this URI. -1 is used to indicate that the port is
    * not specified, otherwise valid port numbers are  between 0 and 65535.
    * If a valid port number is passed in and the host field is null,
    * an exception is thrown.
    *
    * @param p_port the port number for this URI
    *
    * @exception MalformedURIException if p_port is not -1 and not a
    *                                  valid port number
    */
   private void setPort(int p_port) throws MalformedURIException {
     if (p_port >= 0 && p_port <= 65535) {
       if (m_host == null) {
         throw new MalformedURIException("Port cannot be set when host is null!");
       }
     } else if (p_port != -1) {
       throw new MalformedURIException("Invalid port number!");
     }
     n_port = p_port;
 
   }
 
   /**
    * Set the path for this URI. If the supplied path is null, then the
    * query string and fragment are set to null as well. If the supplied
    * path includes a query string and/or fragment, these fields will be
    * parsed and set as well. Note that, for URIs following the "generic
    * URI" syntax, the path specified should start with a slash.
    * For URIs that do not follow the generic URI syntax, this method
    * sets the scheme-specific part.
    *
    * @param p_path the path for this URI (may be null)
    *
    * @exception MalformedURIException if p_path contains invalid
    *                                  characters
    */
   private void setPath(String p_path) throws MalformedURIException {
     if (p_path == null) {
       m_path = null;
       m_queryString = null;
       m_fragment = null;
     } else {
      initializePath(p_path);
    }
  }

  /**
   * Append to the end of the path of this URI. If the current path does
   * not end in a slash and the path to be appended does not begin with
   * a slash, a slash will be appended to the current path before the
   * new segment is added. Also, if the current path ends in a slash
   * and the new segment begins with a slash, the extra slash will be
   * removed before the new segment is appended.
   *
   * @param p_addToPath the new segment to be added to the current path
   *
   * @exception MalformedURIException if p_addToPath contains syntax
   *                                  errors
   */
  private void appendPath(String p_addToPath) throws MalformedURIException {
    if (p_addToPath == null || p_addToPath.length() == 0) {
      return;
    }

    if (!isURIString(p_addToPath)) {
      throw new MalformedURIException("Path contains invalid character!");
    }

    if (m_path == null || m_path.length() == 0) {
      if (p_addToPath.startsWith("/")) {
        m_path = p_addToPath;
      } else {
        m_path = "/" + p_addToPath;
      }
    } else if (m_path.endsWith("/")) {
      if (p_addToPath.startsWith("/")) {
        m_path = m_path.concat(p_addToPath.substring(1));
      } else {
        m_path = m_path.concat(p_addToPath);
      }
    } else {
      if (p_addToPath.startsWith("/")) {
        m_path = m_path.concat(p_addToPath);
      } else {
        m_path = m_path.concat("/" + p_addToPath);
      }
    }
  }

  /**
   * Set the query string for this URI. A non-null value is valid only
   * if this is an URI conforming to the generic URI syntax and
   * the path value is not null.
   *
   * @param p_queryString the query string for this URI
   *
   * @exception MalformedURIException if p_queryString is not null and this
   *                                  URI does not conform to the generic
   *                                  URI syntax or if the path is null
   */
  private void setQueryString(String p_queryString)
    throws MalformedURIException {
    if (p_queryString == null) {
      m_queryString = null;
    } else if (!isGenericURI()) {
      throw new MalformedURIException("Query string can only be set for a generic URI!");
    } else if (getPath() == null) {
      throw new MalformedURIException("Query string cannot be set when path is null!");
    } else if (!isURIString(p_queryString)) {
      throw new MalformedURIException("Query string contains invalid character!");
    } else {
      m_queryString = p_queryString;
    }
  }

  /**
   * Set the fragment for this URI. A non-null value is valid only
   * if this is a URI conforming to the generic URI syntax and
   * the path value is not null.
   *
   * @param p_fragment the fragment for this URI
   *
   * @exception MalformedURIException if p_fragment is not null and this
   *                                  URI does not conform to the generic
   *                                  URI syntax or if the path is null
   */
  public void setFragment(String p_fragment) throws MalformedURIException {
    if (p_fragment == null) {
      m_fragment = null;
    } else if (!isGenericURI()) {
      throw new MalformedURIException("Fragment can only be set for a generic URI!");
    } else if (getPath() == null) {
      throw new MalformedURIException("Fragment cannot be set when path is null!");
    } else if (!isURIString(p_fragment)) {
      throw new MalformedURIException("Fragment contains invalid character!");
    } else {
      m_fragment = p_fragment;
    }
  }

  /**
   * Determines if the passed-in Object is equivalent to this URI.
   *
   * @param p_test the Object to test for equality.
   *
   * @return true if p_test is a URI with all values equal to this
   *         URI, false otherwise
   */
  public boolean equals(Object p_test) {
    if (p_test instanceof URI) {
      URI testURI = (URI) p_test;
      if (((m_scheme == null && testURI.m_scheme == null)
        || (m_scheme != null
          && testURI.m_scheme != null
          && m_scheme.equals(testURI.m_scheme)))
        && ((m_userinfo == null && testURI.m_userinfo == null)
          || (m_userinfo != null
            && testURI.m_userinfo != null
            && m_userinfo.equals(testURI.m_userinfo)))
        && ((m_host == null && testURI.m_host == null)
          || (m_host != null
            && testURI.m_host != null
            && m_host.equals(testURI.m_host)))
        && ((m_port == null && testURI.m_port == null)
          || (m_port != null
            && testURI.m_port != null
            && m_port.equals(testURI.m_port)))
        && ((m_path == null && testURI.m_path == null)
          || (m_path != null
            && testURI.m_path != null
            && m_path.equals(testURI.m_path)))
        && ((m_queryString == null && testURI.m_queryString == null)
          || (m_queryString != null
            && testURI.m_queryString != null
            && m_queryString.equals(testURI.m_queryString)))
        && ((m_fragment == null && testURI.m_fragment == null)
          || (m_fragment != null
            && testURI.m_fragment != null
            && m_fragment.equals(testURI.m_fragment)))) {
        return true;
      }
    }
    return false;
  }


    /**
        produce a human-consumable string for the URI
    */
  public String toString() 
        { return getURIString(); }
    
    /**
     * Get the URI as a string specification. See RFC 2396 Section 5.2.
     *
     * @return the URI string specification
     */
    public String getURIString() {
    StringBuffer uriSpecString = new StringBuffer();

    if (m_scheme != null) {
      uriSpecString.append(m_scheme);
      uriSpecString.append(':');
    }
    uriSpecString.append(getSchemeSpecificPart());
    return uriSpecString.toString();
  }

    public int hashCode() {
        return toString().hashCode();
    }
    
  /**
   * Get the indicator as to whether this URI uses the "generic URI"
   * syntax.
   *
   * @return true if this URI uses the "generic URI" syntax, false
   *         otherwise
   */
  public boolean isGenericURI() {
    // presence of the host (whether valid or empty) means
    // double-slashes which means generic uri
    return (m_host != null);
  }

  /**
   * Determine whether a scheme conforms to the rules for a scheme name.
   * A scheme is conformant if it starts with an alphanumeric, and
   * contains only alphanumerics, '+','-' and '.'.
   *
   * @return true if the scheme is conformant, false otherwise
   */
  public static boolean isConformantSchemeName(String p_scheme) {
    if (p_scheme == null || p_scheme.length() == 0) {
      return false;
    }

    if (!isAlpha(p_scheme.charAt(0))) {
      return false;
    }

    char testChar;
    for (int i = 1; i < p_scheme.length(); i++) {
      testChar = p_scheme.charAt(i);
      if (!isAlphanum(testChar)
        && SCHEME_CHARACTERS.indexOf(testChar) == -1) {
        return false;
      }
    }

    return true;
  }

  /**
   * Determine whether a string is syntactically capable of representing
   * a valid IPv4 address or the domain name of a network host. A valid
   * IPv4 address consists of four decimal digit groups separated by a
   * '.'. A hostname consists of domain labels (each of which must
   * begin and end with an alphanumeric but may contain '-') separated
   & by a '.'. See RFC 2396 Section 3.2.2.
   *
   * @return true if the string is a syntactically valid IPv4 address
   *              or hostname
   */
  public static boolean isWellFormedAddress(String p_address) {
    if (p_address == null) {
      return false;
    }

    String address = p_address;
    int addrLength = address.length();
    if (addrLength == 0 || addrLength > 255) {
      return false;
    }

    if (address.startsWith(".") || address.startsWith("-")) {
      return false;
    }

    // rightmost domain label starting with digit indicates IP address
    // since top level domain label can only start with an alpha
    // see RFC 2396 Section 3.2.2
    int index = address.lastIndexOf('.');
    if (address.endsWith(".")) {
      index = address.substring(0, index).lastIndexOf('.');
    }

    if (index + 1 < addrLength && isDigit(p_address.charAt(index + 1))) {
      char testChar;
      int numDots = 0;

      // make sure that 1) we see only digits and dot separators, 2) that
      // any dot separator is preceded and followed by a digit and
      // 3) that we find 3 dots
      for (int i = 0; i < addrLength; i++) {
        testChar = address.charAt(i);
        if (testChar == '.') {
          if (!isDigit(address.charAt(i - 1))
            || (i + 1 < addrLength
              && !isDigit(address.charAt(i + 1)))) {
            return false;
          }
          numDots++;
        } else if (!isDigit(testChar)) {
          return false;
        }
      }
      if (numDots != 3) {
        return false;
      }
    } else {
      // domain labels can contain alphanumerics and '-"
      // but must start and end with an alphanumeric
      char testChar;

      for (int i = 0; i < addrLength; i++) {
        testChar = address.charAt(i);
        if (testChar == '.') {
          if (!isAlphanum(address.charAt(i - 1))) {
            return false;
          }
          if (i + 1 < addrLength
            && !isAlphanum(address.charAt(i + 1))) {
            return false;
          }
        } else if (!isAlphanum(testChar) && testChar != '-') {
          return false;
        }
      }
    }
    return true;
  }

  /**
   * Determine whether a char is a digit.
   *
   * @return true if the char is betweeen '0' and '9', false otherwise
   */
  private static boolean isDigit(char p_char) {
    return p_char >= '0' && p_char <= '9';
  }

  /**
   * Determine whether a character is a hexadecimal character.
   *
   * @return true if the char is betweeen '0' and '9', 'a' and 'f'
   *         or 'A' and 'F', false otherwise
   */
  private static boolean isHex(char p_char) {
    return (
      isDigit(p_char)
        || (p_char >= 'a' && p_char <= 'f')
        || (p_char >= 'A' && p_char <= 'F'));
  }

  /**
   * Determine whether a char is an alphabetic character: a-z or A-Z
   *
   * @return true if the char is alphabetic, false otherwise
   */
  private static boolean isAlpha(char p_char) {
    return (
      (p_char >= 'a' && p_char <= 'z')
        || (p_char >= 'A' && p_char <= 'Z'));
  }

  /**
   * Determine whether a char is an alphanumeric: 0-9, a-z or A-Z
   *
   * @return true if the char is alphanumeric, false otherwise
   */
  private static boolean isAlphanum(char p_char) {
    return (isAlpha(p_char) || isDigit(p_char));
  }

  /**
   * Determine whether a character is a reserved character:
   * ';', '/', '?', ':', '@', '&', '=', '+', '$' or ','
   *
   * @return true if the string contains any reserved characters
   */
  private static boolean isReservedCharacter(char p_char) {
    return RESERVED_CHARACTERS.indexOf(p_char) != -1;
  }

  /**
   * Determine whether a char is an unreserved character.
   *
   * @return true if the char is unreserved, false otherwise
   */
  private static boolean isUnreservedCharacter(char p_char) {
    return (!isReservedCharacter(p_char)) && "#%[]".indexOf(p_char) == -1;
    //   return (isAlphanum(p_char) ||
    //           MARK_CHARACTERS.indexOf(p_char) != -1);
  }

  private boolean haveCheckedNFC = false;
  private boolean isNFC;

  public boolean isNormalFormC() {
    if (!haveCheckedNFC) {
      isNFC = CharacterModel.isNormalFormC(toString());
      haveCheckedNFC = true;
    }
    return isNFC;
  }
  /**
   * Determine whether a given string contains only URI characters (also
   * called "uric" in RFC 2396). uric consist of all reserved
   * characters, unreserved characters and escaped characters.
   *
   * @return true if the string is comprised of uric, false otherwise
   */
  private static boolean isURIString(String p_uric) {
    if (p_uric == null) {
      return false;
    }
    int end = p_uric.length();
    char testChar = '\0';
    for (int i = 0; i < end; i++) {
      testChar = p_uric.charAt(i);
      if (testChar == '%') {
        if (i + 2 >= end
          || !isHex(p_uric.charAt(i + 1))
          || !isHex(p_uric.charAt(i + 2))) {
          return false;
        } else {
          i += 2;
          continue;
        }
      }
      if (isReservedCharacter(testChar)
        || isUnreservedCharacter(testChar)) {
        continue;
      } else {
        return false;
      }
    }
    return true;
  }

  /* RELATIVIZE */

  static final public int SAMEDOCUMENT = 1;
  static final public int NETWORK = 2;
  static final public int ABSOLUTE = 4;
  static final public int RELATIVE = 8;
  static final public int PARENT = 16;
  static final public int GRANDPARENT = 32;

  private boolean equal(String s1, String s2) {
    return s1 == null ? s2 == null : s1.equals(s2);
  }
    static private int prefs[][] = {
        { RELATIVE, RELATIVE|PARENT|GRANDPARENT },
        { PARENT, PARENT|GRANDPARENT },
        { GRANDPARENT, GRANDPARENT }
    };
    static String exact[] = { ".", "..", "../.." };
    static String sub[] = { "", "../", "../../" };
  public String relativize(String abs, int flags) throws MalformedURIException {
    URI r;
      r = new URI(abs);
       // logger.info("<"+Util.substituteStandardEntities(abs)+">");
       // logger.info("<"+Util.substituteStandardEntities(r.m_path)+">");
    if (r.isGenericURI()) {
      boolean net = equal(r.m_scheme, m_scheme);
</