uri.java

这是linux下ssl vpn的实现程序

   */
  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;
  }

  /**
   * 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();
  }

  /**
   * 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;
  }
}