/*
    * The Apache Software License, Version 1.1
    *
    *
    * Copyright (c) 1999 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 "Xalan" 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
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   * 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, Lotus
   * Development Corporation., http://www.lotus.com.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   */
  package org.backsource.utils.resource;
  
  import java.io.IOException;
  import java.io.Serializable;
  import java.net.URL;
  import java.net.MalformedURLException;
  
  /***
   *<p> A class to represent a Uniform Resource Identifier (URI) and to get a
   * valid URL representation from the URI.
   *
   * <p>The URL conversion is done with the help of URIFactory, see {@link URIFactory} for more information.
   *
   * <p>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 1.1.1.1 2004/05/19 12:07:31 pra Exp $
   *
  */
 public class URI implements Serializable
 {
 
     /*** 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.
      *  @serial */
     private String m_scheme = null;
 
     /*** If specified, stores the userinfo for this URI; otherwise null.
      *  @serial */
     private String m_userinfo = null;
 
     /*** If specified, stores the host for this URI; otherwise null.
      *  @serial */
     private String m_host = null;
 
     /*** If specified, stores the port for this URI; otherwise -1.
      *  @serial */
     private int m_port = -1;
 
     /*** If specified, stores the path for this URI; otherwise null.
      *  @serial */
     private String m_path = null;
 
     /***
      * If specified, stores the query string for this URI; otherwise
      *   null. 
      * @serial 
      */
     private String m_queryString = null;
 
     /*** If specified, stores the fragment for this URI; otherwise null.
      *  @serial */
     private String m_fragment = null;
 
     /*** Indicate whether in DEBUG mode          */
     private static boolean DEBUG = false;
 
     private URIFactory uriFactory = null;
     
 
     /***
      * 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)
      *
      * @throws 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 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)
      * @param factory an URIFactorty to use for constructing an URL.
      * @throws MalformedURIException if p_uriSpec violates any syntax
      *                                   rules
      */
     public URI(String p_uriSpec, URIFactory factory) throws MalformedURIException
     {
 	this((URI) null, p_uriSpec);
 	this.uriFactory = factory;
     }
 
     /***
      * 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)
      *
      * @throws 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)
      *
      * @throws MalformedURIException if p_scheme violates any
      *                                  syntax rules
      */
     public URI(String p_scheme, String p_schemeSpecificPart)
 	throws MalformedURIException
     {
 
 	if (p_scheme == null || p_scheme.trim().length() == 0)
 	    {
 		throw new MalformedURIException(
 						"Cannot construct URI with null/empty scheme!");
 	    }
 
 	if (p_schemeSpecificPart == null
             || p_schemeSpecificPart.trim().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)
      *
      * @throws 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)
      *
      * @throws 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.trim().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);
 	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.getPort();
 	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)
      *
      * @throws 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.trim().length() == 0))
 	    {
 		throw new MalformedURIException(
 						"Cannot initialize URI with empty parameters.");
 	    }
 
 	// just make a copy of the base if spec is empty
 	if (p_uriSpec == null || p_uriSpec.trim().length() == 0)
 	    {
 		initialize(p_base);
 
 		return;
 	    }
 
 	String uriSpec = p_uriSpec.trim();
 	int uriSpecLen = uriSpec.length();
 	int index = 0;
 
 	// check for scheme
 	if (uriSpec.indexOf(':') == -1)
 	    {
 		if (p_base == null)
 		    {
 			uriSpec = "default:" + uriSpec;
 			uriSpecLen = uriSpec.length();
 			//throw new MalformedURIException("No scheme found in URI: "+uriSpec);
 		    }
 	    }
 	//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.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.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 = new String();
 		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;
 		String tempString = null;
 		
 		while ((index = path.indexOf("/../", index)) > 0) {
 		    tempString = path.substring(0, path.indexOf("/../"));
 		    segIndex = tempString.lastIndexOf('/');
 		    if (segIndex != -1) {
 			if (!tempString.substring(segIndex).equals("..")) {
 			    path = path.substring(0, segIndex+1).concat(path.substring(index+4));
 			    index = segIndex;
 			}
 			else
 			    index += 4;
 		    }
 		    else
 			index += 4;
 		}
 		
 		
 		// 6f - remove ending "<segment>/.." where "<segment>" is a 
 		// complete path segment
 		if (path.endsWith("/.."))
 		    {
 			tempString = path.substring(0, path.length() - 3);
 			segIndex = tempString.lastIndexOf('/');
 			
 			if (segIndex != -1)
 			    {
 				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)
      *
      * @throws MalformedURIException if URI does not have a conformant
      *                                  scheme
      */
     private void initializeScheme(String p_uriSpec) throws MalformedURIException
     {
 
 	int uriSpecLen = p_uriSpec.length();
 	int index = 0;
 	String scheme = null;
 	char testChar = '\0';
 
 	while (index < uriSpecLen)
 	    {
 		testChar = p_uriSpec.charAt(index);
 
 		if (testChar == ':' || testChar == '/' || testChar == '?'
 		    || testChar == '#')
 		    {
 			break;
 		    }
 
 		index++;
 	    }
 
 	scheme = p_uriSpec.substring(0, index);
 
 	if (scheme.length() == 0)
 	    {
 		throw new MalformedURIException("No scheme found in URI.");
 	    }
 	else
 	    {
 		setScheme(scheme);
 	    }
     }
 
     /***
      * Initialize the authority (userinfo, host and port) for this
      * URI from a URI string spec.
      *
      * @param p_uriSpec the URI specification (cannot be null)
      *
      * @throws 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);
 				    }
 				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)
      *
      * @throws 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!");
 			    }
 		    }
 		else if (!isReservedCharacter(testChar)
 			 &&!isUnreservedCharacter(testChar))
 		    {
 			if ('//' != testChar)
 			    throw new MalformedURIException("Path 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!");
 				    }
 			    }
 			else if (!isReservedCharacter(testChar)
 				 &&!isUnreservedCharacter(testChar))
 			    {
 				throw new MalformedURIException(
 								"Query string contains invalid character:" + testChar);
 			    }
 
 			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!");
 				    }
 			    }
 			else if (!isReservedCharacter(testChar)
 				 &&!isUnreservedCharacter(testChar))
 			    {
 				throw new MalformedURIException(
 								"Fragment contains invalid character:" + testChar);
 			    }
 
 			index++;
 		    }
 
 		m_fragment = p_uriSpec.substring(start, index);
 	    }
     }
 
     /***
      * Set the URI factory to use when constructing an URL of the URI.
      *
      * @param factory a URIFactory.
      */
     public void setURIFactory(URIFactory factory) {
 	this.uriFactory = factory;
     }
 
 
     /***
      * 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 != -1)
 	    {
 		schemespec.append("//");
 	    }
 
 	if (m_userinfo != null)
 	    {
 		schemespec.append(m_userinfo);
 		schemespec.append('@');
 	    }
 
 	if (m_host != null)
 	    {
 		schemespec.append(m_host);
 	    }
 
 	if (m_port != -1)
 	    {
 		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 m_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)
      *
      * @throws MalformedURIException if p_scheme is not a conformant
      *                                  scheme name
      */
     public 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 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
      *
      * @throws MalformedURIException if p_userinfo contains invalid
      *                                  characters
      */
     public 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
      *
      * @throws MalformedURIException if p_host is not a valid IP
      *                                  address or DNS hostname.
      */
     public void setHost(String p_host) throws MalformedURIException
     {
 
 	if (p_host == null || p_host.trim().length() == 0)
 	    {
 		m_host = p_host;
 		m_userinfo = null;
 		m_port = -1;
 	    }
 	else if (!isWellFormedAddress(p_host))
 	    {
 		throw new MalformedURIException("Host is not a well formed address!");
 	    }
 
 	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
      *
      * @throws MalformedURIException if p_port is not -1 and not a
      *                                  valid port number
      */
     public 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!");
 	    }
 
 	m_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)
      *
      * @throws MalformedURIException if p_path contains invalid
      *                                  characters
      */
     public 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
      *
      * @throws MalformedURIException if p_addToPath contains syntax
      *                                  errors
      */
     public void appendPath(String p_addToPath) throws MalformedURIException
     {
 
 	if (p_addToPath == null || p_addToPath.trim().length() == 0)
 	    {
 		return;
 	    }
 
 	if (!isURIString(p_addToPath))
 	    {
 		throw new MalformedURIException("Path contains invalid character!");
 	    }
 
 	if (m_path == null || m_path.trim().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
      *
      * @throws MalformedURIException if p_queryString is not null and this
      *                                  URI does not conform to the generic
      *                                  URI syntax or if the path is null
      */
     public 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
      *
      * @throws 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 == 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;
     }
 
     /***
      * <p>Get an URL represenation of this URI. 
      *
      * <p>Either an URI factory from URIFactoryContext will be used a factory specifically set on this URI. If the URI is not possible to convert to an URL a MaformedURLException will be thrown. For URI:s fetched/constructed from for example the classloader or the servlet context, this means that a MalformedURLException will be thrown also when the resource was not found.
      *
      * @return URL a valid url for the URI where the resource the URI points to is possible to get.
      * @exception MalformedURLException thrown if the URI is not possible to convert to an URL, i.e does not point to a locatable resource or is not wellformed.
      */
     public URL getURL() throws MalformedURLException{
 	if (uriFactory != null)
 	    return getURL(uriFactory);
 	else
 	    return getURL( URIFactoryContext.get());
     }
     
     /***
      * Get an URL represenation of this URI from the given URIFactory. @see getURL().
      *
      * @param factory an URIFactory to use when constructing the URL.
      * @return URL a valid url for the URI where the resource the URI points to is possible to get.
      * @exception MalformedURLException thrown if the URI is not possible to convert to an URL, i.e does not point to a locatable resource or is not wellformed.
      */
     public URL getURL(URIFactory factory) throws MalformedURLException{
 	return factory.getURL(this);
     }
 
     /***
      * Get the URI as a string specification. See RFC 2396 Section 5.2.
      *
      * @return the URI string specification
      */
     public String toString()
     {
 
 	StringBuffer uriSpecString = new StringBuffer();
 
 	if (m_scheme != null)
 	    {
 		uriSpecString.append(m_scheme);
 		uriSpecString.append(':');
 	    }
 
 	uriSpecString.append(getSchemeSpecificPart());
 
 	return uriSpecString.toString();
     }
 
     public String toExternalForm() {
 	return toString();
     }
 
     /***
      * 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 '.'.
      *
      *
      * @param p_scheme The sheme name to check
      * @return true if the scheme is conformant, false otherwise
      */
     public static boolean isConformantSchemeName(String p_scheme)
     {
 
 	if (p_scheme == null || p_scheme.trim().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.
      *
      *
      * @param p_address The address string to check
      * @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.trim();
 	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.
      *
      *
      * @param p_char the character to check
      * @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.
      *
      *
      * @param p_char the character to check
      * @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
      *
      *
      * @param p_char the character to check
      * @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
      *
      *
      * @param p_char the character to check
      * @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 ','
      *
      *
      * @param p_char the character to check
      * @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.
      *
      *
      * @param p_char the character to check
      * @return true if the char is unreserved, false otherwise
      */
     private static boolean isUnreservedCharacter(char p_char)
     {
 	return (isAlphanum(p_char) || MARK_CHARACTERS.indexOf(p_char) != -1);
     }
 
     /***
      * 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.
      *
      *
      * @param p_uric URI string
      * @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;
     }
 }