uri.java

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/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: URI.java,v 1.1.4.1 2005/09/08 11:03:20 suresh_emailid Exp $
 */
package com.sun.org.apache.xml.internal.serializer.utils;

import java.io.IOException;
import java.io.Serializable;


/**
 * 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.
 *
 * This class is a copy of the one in com.sun.org.apache.xml.internal.utils. 
 * It exists to cut the serializers dependancy on that package.
 * 
 * A minor change from the original is that this class no longer implements
 * Serializable, and the serialVersionUID magic field is dropped, and
 * the class is no longer "public".
 *  
 * @xsl.usage internal
 */
final class URI
{
  /**
   * MalformedURIExceptions are thrown in the process of building a URI
   * or setting fields on a URI when an operation would result in an
   * invalid URI specification.
   *
   */
  public static class MalformedURIException extends IOException
  {

    /**
     * Constructs a <code>MalformedURIException</code> with no specified
     * detail message.
     */
    public MalformedURIException()
    {
      super();
    }

    /**
     * Constructs a <code>MalformedURIException</code> with the
     * specified detail message.
     *
     * @param p_msg the detail message.
     */
    public MalformedURIException(String p_msg)
    {
      super(p_msg);
    }
  }

  /** 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;

  /**
   * 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 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(Utils.messages.createMessage(MsgKey.ER_SCHEME_REQUIRED, null)); //"Scheme is required!");
    }

    if (p_host == null)
    {
      if (p_userinfo != null)
      {
        throw new MalformedURIException(
          Utils.messages.createMessage(MsgKey.ER_NO_USERINFO_IF_NO_HOST, null)); //"Userinfo may not be specified if host is not specified!");
      }

      if (p_port != -1)
      {
        throw new MalformedURIException(
          Utils.messages.createMessage(MsgKey.ER_NO_PORT_IF_NO_HOST, null)); //"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(
          Utils.messages.createMessage(MsgKey.ER_NO_QUERY_STRING_IN_PATH, null)); //"Query string cannot be specified in path and query string!");
      }

      if (p_path.indexOf('#') != -1 && p_fragment != null)
      {
        throw new MalformedURIException(
          Utils.messages.createMessage(MsgKey.ER_NO_FRAGMENT_STRING_IN_PATH, null)); //"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(
        Utils.messages.createMessage(MsgKey.ER_CANNOT_INIT_URI_EMPTY_PARMS, null)); //"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
    int colonIndex = uriSpec.indexOf(':');
    if (colonIndex < 0)
    {
      if (p_base == null)
      {
        throw new MalformedURIException(Utils.messages.createMessage(MsgKey.ER_NO_SCHEME_IN_URI, new Object[]{uriSpec})); //"No scheme found in URI: "+uriSpec);
      }
    }
    else
    {
      initializeScheme(uriSpec);
      uriSpec = uriSpec.substring(colonIndex+1);
      uriSpecLen = uriSpec.length();
    }

    // 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';