/*
 * Copyright 2005 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package java.net;

import java.util.List;
import java.util.StringTokenizer;
import java.util.NoSuchElementException;
import java.text.SimpleDateFormat;
import java.util.TimeZone;
import java.util.Date;

import java.lang.NullPointerException;  // for javadoc

/**
 * An HttpCookie object represents an http cookie, which carries state
 * information between server and user agent. Cookie is widely adopted
 * to create stateful sessions.
 *
 * <p>There are 3 http cookie specifications:
 * <blockquote>
 *   Netscape draft<br>
 *   RFC 2109 - <a href="http://www.ietf.org/rfc/rfc2109.txt">
 * <i>http://www.ietf.org/rfc/rfc2109.txt</i></a><br>
 *   RFC 2965 - <a href="http://www.ietf.org/rfc/rfc2965.txt">
 * <i>http://www.ietf.org/rfc/rfc2965.txt</i></a>
 * </blockquote>
 *
 * <p>HttpCookie class can accept all these 3 forms of syntax.
 *
 * @author Edward Wang
 * @since 1.6
 */
public final class HttpCookie implements Cloneable {
    /* ---------------- Fields -------------- */

    //
    // The value of the cookie itself.
    //

    private String name;        // NAME= ... "$Name" style is reserved
    private String value;       // value of NAME

    //
    // Attributes encoded in the header's cookie fields.
    //

    private String comment;     // Comment=VALUE ... describes cookie's use
    private String commentURL;  // CommentURL="http URL" ... describes cookie's use
    private boolean toDiscard;  // Discard ... discard cookie unconditionally
    private String domain;      // Domain=VALUE ... domain that sees cookie
    private long maxAge = MAX_AGE_UNSPECIFIED;  // Max-Age=VALUE ... cookies auto-expire
    private String path;        // Path=VALUE ... URLs that see the cookie
    private String portlist;    // Port[="portlist"] ... the port cookie may be returned to
    private boolean secure;     // Secure ... e.g. use SSL
    private int version = 1;    // Version=1 ... RFC 2965 style

    //
    // Hold the creation time (in seconds) of the http cookie for later
    // expiration calculation
    //
    private long whenCreated = 0;


    //
    // Since the positive and zero max-age have their meanings,
    // this value serves as a hint as 'not specify max-age'
    //
    private final static long MAX_AGE_UNSPECIFIED = -1;


    //
    // date format used by Netscape's cookie draft
    //
    private final static String NETSCAPE_COOKIE_DATE_FORMAT = "EEE',' dd-MMM-yyyy HH:mm:ss 'GMT'";

    //
    // constant strings represent set-cookie header token
    //
    private final static String SET_COOKIE = "set-cookie:";
    private final static String SET_COOKIE2 = "set-cookie2:";


    /* ---------------- Ctors -------------- */

    /**
     * Constructs a cookie with a specified name and value.
     *
     * <p>The name must conform to RFC 2965. That means it can contain
     * only ASCII alphanumeric characters and cannot contain commas,
     * semicolons, or white space or begin with a $ character. The cookie's
     * name cannot be changed after creation.
     *
     * <p>The value can be anything the server chooses to send. Its
     * value is probably of interest only to the server. The cookie's
     * value can be changed after creation with the
     * <code>setValue</code> method.
     *
     * <p>By default, cookies are created according to the RFC 2965
     * cookie specification. The version can be changed with the
     * <code>setVersion</code> method.
     *
     *
     * @param name                      a <code>String</code> specifying the name of the cookie
     *
     * @param value                     a <code>String</code> specifying the value of the cookie
     *
     * @throws IllegalArgumentException if the cookie name contains illegal characters
     *                                  or it is one of the tokens reserved for use
     *                                  by the cookie protocol
     * @throws NullPointerException     if <tt>name</tt> is <tt>null</tt>
     * @see #setValue
     * @see #setVersion
     *
     */

    public HttpCookie(String name, String value) {
        name = name.trim();
        if (name.length() == 0 || !isToken(name) || isReserved(name)) {
            throw new IllegalArgumentException("Illegal cookie name");
        }

        this.name = name;
        this.value = value;
        toDiscard = false;
        secure = false;

        whenCreated = System.currentTimeMillis();
    }


    /**
     * Constructs cookies from set-cookie or set-cookie2 header string.
     * RFC 2965 section 3.2.2 set-cookie2 syntax indicates that one header line
     * may contain more than one cookie definitions, so this is a static
     * utility method instead of another constructor.
     *
     * @param header    a <tt>String</tt> specifying the set-cookie header.
     *                  The header should start with "set-cookie", or "set-cookie2"
     *                  token; or it should have no leading token at all.
     * @return          a List of cookie parsed from header line string
     * @throws IllegalArgumentException if header string violates the cookie
     *                                  specification's syntax, or the cookie
     *                                  name contains llegal characters, or
     *                                  the cookie name is one of the tokens
     *                                  reserved for use by the cookie protocol
     * @throws NullPointerException     if the header string is <tt>null</tt>
     */
    public static List<HttpCookie> parse(String header) {
        int version = guessCookieVersion(header);

        // if header start with set-cookie or set-cookie2, strip it off
        if (startsWithIgnoreCase(header, SET_COOKIE2)) {
            header = header.substring(SET_COOKIE2.length());
        } else if (startsWithIgnoreCase(header, SET_COOKIE)) {
            header = header.substring(SET_COOKIE.length());
        }


        List<HttpCookie> cookies = new java.util.ArrayList<HttpCookie>();
        // The Netscape cookie may have a comma in its expires attribute,
        // while the comma is the delimiter in rfc 2965/2109 cookie header string.
        // so the parse logic is slightly different
        if (version == 0) {
            // Netscape draft cookie
            HttpCookie cookie = parseInternal(header);
            cookie.setVersion(0);
            cookies.add(cookie);
        } else {
            // rfc2965/2109 cookie
            // if header string contains more than one cookie,
            // it'll separate them with comma
            List<String> cookieStrings = splitMultiCookies(header);
            for (String cookieStr : cookieStrings) {
                HttpCookie cookie = parseInternal(cookieStr);
                cookie.setVersion(1);
                cookies.add(cookie);
            }
        }

        return cookies;
    }


    /* ---------------- Public operations -------------- */


    /**
     * Reports whether this http cookie has expired or not.
     *
     * @return  <tt>true</tt> to indicate this http cookie has expired;
     *          otherwise, <tt>false</tt>
     */
    public boolean hasExpired() {
        if (maxAge == 0) return true;

        // if not specify max-age, this cookie should be
        // discarded when user agent is to be closed, but
        // it is not expired.
        if (maxAge == MAX_AGE_UNSPECIFIED) return false;

        long deltaSecond = (System.currentTimeMillis() - whenCreated) / 1000;
        if (deltaSecond > maxAge)
            return true;
        else
            return false;
    }

    /**
     *
     * Specifies a comment that describes a cookie's purpose.
     * The comment is useful if the browser presents the cookie
     * to the user. Comments
     * are not supported by Netscape Version 0 cookies.
     *
     * @param purpose           a <code>String</code> specifying the comment
     *                          to display to the user
     *
     * @see #getComment
     *
     */

    public void setComment(String purpose) {
        comment = purpose;
    }


    /**
     * Returns the comment describing the purpose of this cookie, or
     * <code>null</code> if the cookie has no comment.
     *
     * @return                  a <code>String</code> containing the comment,
     *                          or <code>null</code> if none
     *
     * @see #setComment
     *
     */

    public String getComment() {
        return comment;
    }


    /**
     *
     * Specifies a comment url that describes a cookie's purpose.
     * The comment url is useful if the browser presents the cookie
     * to the user. Comment url is RFC 2965 only.
     *
     * @param purpose           a <code>String</code> specifying the comment url
     *                          to display to the user
     *
     * @see #getCommentURL
     *
     */

    public void setCommentURL(String purpose) {
        commentURL = purpose;
    }


    /**
     * Returns the comment url describing the purpose of this cookie, or
     * <code>null</code> if the cookie has no comment url.
     *
     * @return                  a <code>String</code> containing the comment url,
     *                          or <code>null</code> if none
     *
     * @see #setCommentURL
     *
     */

    public String getCommentURL() {
        return commentURL;
    }


    /**
     * Specify whether user agent should discard the cookie unconditionally.
     * This is RFC 2965 only attribute.
     *
     * @param discard   <tt>true</tt> indicates to discard cookie unconditionally
     *
     * @see #getDiscard
     */

    public void setDiscard(boolean discard) {
        toDiscard = discard;
    }


    /**
     * Return the discard attribute of the cookie
     *
     * @return  a <tt>boolean</tt> to represent this cookie's discard attribute
     *
     * @see #setDiscard
     */

    public boolean getDiscard() {
        return toDiscard;
    }


    /**
     * Specify the portlist of the cookie, which restricts the port(s)
     * to which a cookie may be sent back in a Cookie header.
     *
     * @param ports     a <tt>String</tt> specify the port list, which is
     *                  comma seperated series of digits
     * @see #getPortlist
     */

    public void setPortlist(String ports) {
        portlist = ports;
    }


    /**
     * Return the port list attribute of the cookie
     *
     * @return  a <tt>String</tt> contains the port list
     *          or <tt>null</tt> if none
     * @see #setPortlist
     */

    public String getPortlist() {
        return portlist;
    }

    /**
     *
     * Specifies the domain within which this cookie should be presented.
     *
     * <p>The form of the domain name is specified by RFC 2965. A domain
     * name begins with a dot (<code>.foo.com</code>) and means that
     * the cookie is visible to servers in a specified Domain Name System
     * (DNS) zone (for example, <code>www.foo.com</code>, but not
     * <code>a.b.foo.com</code>). By default, cookies are only returned
     * to the server that sent them.
     *
     *
     * @param pattern           a <code>String</code> containing the domain name
     *                          within which this cookie is visible;
     *                          form is according to RFC 2965
     *
     * @see #getDomain
     *
     */

    public void setDomain(String pattern) {
        if (pattern != null)
            domain = pattern.toLowerCase();
        else
            domain = pattern;
    }


    /**
     * Returns the domain name set for this cookie. The form of
     * the domain name is set by RFC 2965.
     *
     * @return                  a <code>String</code> containing the domain name
     *
     * @see #setDomain
     *
     */

    public String getDomain() {
        return domain;
    }


    /**
     * Sets the maximum age of the cookie in seconds.
     *
     * <p>A positive value indicates that the cookie will expire
     * after that many seconds have passed. Note that the value is
     * the <i>maximum</i> age when the cookie will expire, not the cookie's
     * current age.
     *
     * <p>A negative value means
     * that the cookie is not stored persistently and will be deleted
     * when the Web browser exits. A zero value causes the cookie
     * to be deleted.
     *
     * @param expiry            an integer specifying the maximum age of the
     *                          cookie in seconds; if zero, the cookie
     *                          should be discarded immediately;
     *                          otherwise, the cookie's max age is unspecified.
     *
     * @see #getMaxAge
     *
     */
    public void setMaxAge(long expiry) {
        maxAge = expiry;
    }


    /**
     * Returns the maximum age of the cookie, specified in seconds.
     * By default, <code>-1</code> indicating the cookie will persist
     * until browser shutdown.
     *
     *
     * @return                  an integer specifying the maximum age of the
     *                          cookie in seconds
     *
     *
     * @see #setMaxAge
     *
     */

    public long getMaxAge() {
        return maxAge;
    }


    /**
     * Specifies a path for the cookie
     * to which the client should return the cookie.
     *
     * <p>The cookie is visible to all the pages in the directory
     * you specify, and all the pages in that directory's subdirectories.
     * A cookie's path must include the servlet that set the cookie,
     * for example, <i>/catalog</i>, which makes the cookie
     * visible to all directories on the server under <i>/catalog</i>.
     *
     * <p>Consult RFC 2965 (available on the Internet) for more
     * information on setting path names for cookies.
     *
     *
     * @param uri               a <code>String</code> specifying a path
     *
     *
     * @see #getPath
     *
     */

    public void setPath(String uri) {
        path = uri;
    }


    /**
     * Returns the path on the server
     * to which the browser returns this cookie. The
     * cookie is visible to all subpaths on the server.
     *
     *
     * @return          a <code>String</code> specifying a path that contains
     *                  a servlet name, for example, <i>/catalog</i>
     *
     * @see #setPath
     *
     */

    public String getPath() {
        return path;
    }


    /**
     * Indicates to the browser whether the cookie should only be sent
     * using a secure protocol, such as HTTPS or SSL.
     *
     * <p>The default value is <code>false</code>.
     *
     * @param flag      if <code>true</code>, sends the cookie from the browser
     *                  to the server using only when using a secure protocol;
     *                  if <code>false</code>, sent on any protocol
     *
     * @see #getSecure
     *
     */

    public void setSecure(boolean flag) {
        secure = flag;
    }


    /**
     * Returns <code>true</code> if the browser is sending cookies
     * only over a secure protocol, or <code>false</code> if the
     * browser can send cookies using any protocol.
     *
     * @return          <code>true</code> if the browser can use
     *                  any standard protocol; otherwise, <code>false</code>
     *
     * @see #setSecure
     *
     */

    public boolean getSecure() {
        return secure;
    }


    /**
     * Returns the name of the cookie. The name cannot be changed after
     * creation.
     *
     * @return          a <code>String</code> specifying the cookie's name
     *
     */

    public String getName() {
        return name;
    }


    /**
     *
     * Assigns a new value to a cookie after the cookie is created.
     * If you use a binary value, you may want to use BASE64 encoding.
     *
     * <p>With Version 0 cookies, values should not contain white
     * space, brackets, parentheses, equals signs, commas,
     * double quotes, slashes, question marks, at signs, colons,
     * and semicolons. Empty values may not behave the same way
     * on all browsers.
     *
     * @param newValue          a <code>String</code> specifying the new value
     *
     *
     * @see #getValue
     *
     */

    public void setValue(String newValue) {
        value = newValue;
    }


    /**
     * Returns the value of the cookie.
     *
     * @return                  a <code>String</code> containing the cookie's
     *                          present value
     *
     * @see #setValue
     *
     */

    public String getValue() {
        return value;
    }


    /**
     * Returns the version of the protocol this cookie complies
     * with. Version 1 complies with RFC 2965/2109,
     * and version 0 complies with the original
     * cookie specification drafted by Netscape. Cookies provided
     * by a browser use and identify the browser's cookie version.
     *
     *
     * @return                  0 if the cookie complies with the
     *                          original Netscape specification; 1
     *                          if the cookie complies with RFC 2965/2109
     *
     * @see #setVersion
     *
     */

    public int getVersion() {
        return version;
    }


    /**
     * Sets the version of the cookie protocol this cookie complies
     * with. Version 0 complies with the original Netscape cookie
     * specification. Version 1 complies with RFC 2965/2109.
     *
     *
     * @param v                 0 if the cookie should comply with
     *                          the original Netscape specification;
     *                          1 if the cookie should comply with RFC 2965/2109
     *
     * @throws IllegalArgumentException if <tt>v</tt> is neither 0 nor 1
     *
     * @see #getVersion
     *
     */

    public void setVersion(int v) {
        if (v != 0 && v != 1) {
            throw new IllegalArgumentException("cookie version should be 0 or 1");
        }

        version = v;
    }


    /**
     * The utility method to check whether a host name is in a domain
     * or not.
     *
     * <p>This concept is described in the cookie specification.
     * To understand the concept, some terminologies need to be defined first:
     * <blockquote>
     * effective host name = hostname if host name contains dot<br>
     * &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;or = hostname.local if not
     * </blockquote>
     * <p>Host A's name domain-matches host B's if:
     * <blockquote><ul>
     *   <li>their host name strings string-compare equal; or</li>
     *   <li>A is a HDN string and has the form NB, where N is a non-empty
     *   name string, B has the form .B', and B' is a HDN string.  (So,
     *   x.y.com domain-matches .Y.com but not Y.com.)</li>
     * </ul></blockquote>
     *
     * <p>A host isn't in a domain (RFC 2965 sec. 3.3.2) if:
     * <blockquote><ul>
     *   <li>The value for the Domain attribute contains no embedded dots,
     *   and the value is not .local.</li>
     *   <li>The effective host name that derives from the request-host does
     *   not domain-match the Domain attribute.</li>
     *   <li>The request-host is a HDN (not IP address) and has the form HD,
     *   where D is the value of the Domain attribute, and H is a string
     *   that contains one or more dots.</li>
     * </ul></blockquote>
     *
     * <p>Examples:
     * <blockquote><ul>
     *   <li>A Set-Cookie2 from request-host y.x.foo.com for Domain=.foo.com
     *   would be rejected, because H is y.x and contains a dot.</li>
     *   <li>A Set-Cookie2 from request-host x.foo.com for Domain=.foo.com
     *   would be accepted.</li>
     *   <li>A Set-Cookie2 with Domain=.com or Domain=.com., will always be
     *   rejected, because there is no embedded dot.</li>
     *   <li>A Set-Cookie2 with Domain=ajax.com will be accepted, and the
     *   value for Domain will be taken to be .ajax.com, because a dot
     *   gets prepended to the value.</li>
     *   <li>A Set-Cookie2 from request-host example for Domain=.local will
     *   be accepted, because the effective host name for the request-
     *   host is example.local, and example.local domain-matches .local.</li>
     * </ul></blockquote>
     *
     * @param domain    the domain name to check host name with
     * @param host      the host name in question
     * @return          <tt>true</tt> if they domain-matches; <tt>false</tt> if not
     */
    public static boolean domainMatches(String domain, String host) {
        if (domain == null || host == null)
            return false;

        // if there's no embedded dot in domain and domain is not .local
        boolean isLocalDomain = ".local".equalsIgnoreCase(domain);
        int embeddedDotInDomain = domain.indexOf('.');
        if (embeddedDotInDomain == 0)
            embeddedDotInDomain = domain.indexOf('.', 1);
        if (!isLocalDomain
            && (embeddedDotInDomain == -1 || embeddedDotInDomain == domain.length() - 1))
            return false;

        // if the host name contains no dot and the domain name is .local
        int firstDotInHost = host.indexOf('.');
        if (firstDotInHost == -1 && isLocalDomain)
            return true;

        int domainLength = domain.length();
        int lengthDiff = host.length() - domainLength;
        if (lengthDiff == 0) {
            // if the host name and the domain name are just string-compare euqal
            return host.equalsIgnoreCase(domain);
        }
        else if (lengthDiff > 0) {
            // need to check H & D component
            String H = host.substring(0, lengthDiff);
            String D = host.substring(lengthDiff);

            return (H.indexOf('.') == -1 && D.equalsIgnoreCase(domain));
        }
        else if (lengthDiff == -1) {
            // if domain is actually .host
            return (domain.charAt(0) == '.' &&
                        host.equalsIgnoreCase(domain.substring(1)));
        }

        return false;
    }


    /**
     * Constructs a cookie header string representation of this cookie,
     * which is in the format defined by corresponding cookie specification,
     * but without the leading "Cookie:" token.
     *
     * @return  a string form of the cookie. The string has the defined format
     */
    public String toString() {
        if (getVersion() > 0) {
            return toRFC2965HeaderString();
        } else {
            return toNetscapeHeaderString();
        }
    }


    /**
     * Test the equality of two http cookies.
     *
     * <p> The result is <tt>true</tt> only if two cookies
     * come from same domain (case-insensitive),
     * have same name (case-insensitive),
     * and have same path (case-sensitive).
     *
     * @return          <tt>true</tt> if 2 http cookies equal to each other;
     *                  otherwise, <tt>false</tt>
     */
    public boolean equals(Object obj) {
        if (obj == this)
            return true;
        if (!(obj instanceof HttpCookie))
            return false;
        HttpCookie other = (HttpCookie)obj;

        // One http cookie equals to another cookie (RFC 2965 sec. 3.3.3) if:
        //   1. they come from same domain (case-insensitive),
        //   2. have same name (case-insensitive),
        //   3. and have same path (case-sensitive).
        return equalsIgnoreCase(getName(), other.getName()) &&
               equalsIgnoreCase(getDomain(), other.getDomain()) &&
               equals(getPath(), other.getPath());
    }


    /**
     * Return hash code of this http cookie. The result is the sum of
     * hash code value of three significant components of this cookie:
     * name, domain, and path.
     * That is, the hash code is the value of the expression:
     * <blockquote>
     * getName().toLowerCase().hashCode()<br>
     * + getDomain().toLowerCase().hashCode()<br>
     * + getPath().hashCode()
     * </blockquote>
     *
     * @return          this http cookie's hash code
     */
    public int hashCode() {
        int h1 = name.toLowerCase().hashCode();
        int h2 = (domain!=null) ? domain.toLowerCase().hashCode() : 0;
        int h3 = (path!=null) ? path.hashCode() : 0;

        return h1 + h2 + h3;
    }

    /**
     * Create and return a copy of this object.
     *
     * @return          a clone of this http cookie
     */
    public Object clone() {
        try {
            return super.clone();
        } catch (CloneNotSupportedException e) {
            throw new RuntimeException(e.getMessage());
        }
    }


    /* ---------------- Private operations -------------- */

    // Note -- disabled for now to allow full Netscape compatibility
    // from RFC 2068, token special case characters
    //
    // private static final String tspecials = "()<>@,;:\\\"/[]?={} \t";
    private static final String tspecials = ",;";

    /*
     * Tests a string and returns true if the string counts as a
     * token.
     *
     * @param value             the <code>String</code> to be tested
     *
     * @return                  <code>true</code> if the <code>String</code> is
     *                          a token; <code>false</code> if it is not
     */

    private static boolean isToken(String value) {
        int len = value.length();

        for (int i = 0; i < len; i++) {
            char c = value.charAt(i);

            if (c < 0x20 || c >= 0x7f || tspecials.indexOf(c) != -1)
                return false;
        }
        return true;
    }


    /*
     * @param name      the name to be tested
     * @return          <tt>true</tt> if the name is reserved by cookie
     *                  specification, <tt>false</tt> if it is not
     */
    private static boolean isReserved(String name) {
        if (name.equalsIgnoreCase("Comment")
            || name.equalsIgnoreCase("CommentURL")      // rfc2965 only
            || name.equalsIgnoreCase("Discard")         // rfc2965 only
            || name.equalsIgnoreCase("Domain")
            || name.equalsIgnoreCase("Expires")         // netscape draft only
            || name.equalsIgnoreCase("Max-Age")
            || name.equalsIgnoreCase("Path")
            || name.equalsIgnoreCase("Port")            // rfc2965 only
            || name.equalsIgnoreCase("Secure")
            || name.equalsIgnoreCase("Version")
            || name.charAt(0) == '$')
        {
            return true;
        }

        return false;
    }


    /*
     * Parse header string to cookie object.
     *
     * @param header    header string; should contain only one NAME=VALUE pair
     *
     * @return          an HttpCookie being extracted
     *
     * @throws IllegalArgumentException if header string violates the cookie
     *                                  specification
     */
    private static HttpCookie parseInternal(String header)
    {
        HttpCookie cookie = null;
        String namevaluePair = null;

        StringTokenizer tokenizer = new StringTokenizer(header, ";");

        // there should always have at least on name-value pair;
        // it's cookie's name
        try {
            namevaluePair = tokenizer.nextToken();
            int index = namevaluePair.indexOf('=');
            if (index != -1) {
                String name = namevaluePair.substring(0, index).trim();
                String value = namevaluePair.substring(index + 1).trim();
                cookie = new HttpCookie(name, stripOffSurroundingQuote(value));
            } else {
                // no "=" in name-value pair; it's an error
                throw new IllegalArgumentException("Invalid cookie name-value pair");
            }
        } catch (NoSuchElementException ignored) {
            throw new IllegalArgumentException("Empty cookie header string");
        }

        // remaining name-value pairs are cookie's attributes
        while (tokenizer.hasMoreTokens()) {
            namevaluePair = tokenizer.nextToken();
            int index = namevaluePair.indexOf('=');
            String name, value;
            if (index != -1) {
                name = namevaluePair.substring(0, index).trim();
                value = namevaluePair.substring(index + 1).trim();
            } else {
                name = namevaluePair.trim();
                value = null;
            }

            // assign attribute to cookie
            assignAttribute(cookie, name, value);
        }

        return cookie;
    }


    /*
     * assign cookie attribute value to attribute name;
     * use a map to simulate method dispatch
     */
    static interface CookieAttributeAssignor {
            public void assign(HttpCookie cookie, String attrName, String attrValue);
    }
    static java.util.Map<String, CookieAttributeAssignor> assignors = null;
    static {
        assignors = new java.util.HashMap<String, CookieAttributeAssignor>();
        assignors.put("comment", new CookieAttributeAssignor(){
                public void assign(HttpCookie cookie, String attrName, String attrValue) {
                    if (cookie.getComment() == null) cookie.setComment(attrValue);
                }
            });
        assignors.put("commenturl", new CookieAttributeAssignor(){
                public void assign(HttpCookie cookie, String attrName, String attrValue) {
                    if (cookie.getCommentURL() == null) cookie.setCommentURL(attrValue);
                }
            });
        assignors.put("discard", new CookieAttributeAssignor(){
                public void assign(HttpCookie cookie, String attrName, String attrValue) {
                    cookie.setDiscard(true);
                }
            });
        assignors.put("domain", new CookieAttributeAssignor(){
                public void assign(HttpCookie cookie, String attrName, String attrValue) {
                    if (cookie.getDomain() == null) cookie.setDomain(attrValue);
                }
            });
        assignors.put("max-age", new CookieAttributeAssignor(){
                public void assign(HttpCookie cookie, String attrName, String attrValue) {
                    try {
                        long maxage = Long.parseLong(attrValue);
                        if (cookie.getMaxAge() == MAX_AGE_UNSPECIFIED) cookie.setMaxAge(maxage);
                    } catch (NumberFormatException ignored) {
                        throw new IllegalArgumentException("Illegal cookie max-age attribute");
                    }
                }
            });
        assignors.put("path", new CookieAttributeAssignor(){
                public void assign(HttpCookie cookie, String attrName, String attrValue) {
                    if (cookie.getPath() == null) cookie.setPath(attrValue);
                }
            });
        assignors.put("port", new CookieAttributeAssignor(){
                public void assign(HttpCookie cookie, String attrName, String attrValue) {
                    if (cookie.getPortlist() == null) cookie.setPortlist(attrValue);
                }
            });
        assignors.put("secure", new CookieAttributeAssignor(){
                public void assign(HttpCookie cookie, String attrName, String attrValue) {
                    cookie.setSecure(true);
                }
            });
        assignors.put("version", new CookieAttributeAssignor(){
                public void assign(HttpCookie cookie, String attrName, String attrValue) {
                    try {
                        int version = Integer.parseInt(attrValue);
                        cookie.setVersion(version);
                    } catch (NumberFormatException ignored) {
                        throw new IllegalArgumentException("Illegal cookie version attribute");
                    }
                }
            });
        assignors.put("expires", new CookieAttributeAssignor(){ // Netscape only
                public void assign(HttpCookie cookie, String attrName, String attrValue) {
                    if (cookie.getMaxAge() == MAX_AGE_UNSPECIFIED) {
                        cookie.setMaxAge(cookie.expiryDate2DeltaSeconds(attrValue));
                    }
                }
            });
    }
    private static void assignAttribute(HttpCookie cookie,
                                       String attrName,
                                       String attrValue)
    {
        // strip off the surrounding "-sign if there's any
        attrValue = stripOffSurroundingQuote(attrValue);

        CookieAttributeAssignor assignor = assignors.get(attrName.toLowerCase());
        if (assignor != null) {
            assignor.assign(cookie, attrName, attrValue);
        } else {
            // must be an error
            throw new IllegalArgumentException("Illegal cookie attribute");
        }
    }

    /*
     * Constructs a string representation of this cookie. The string format is
     * as Netscape spec, but without leading "Cookie:" token.
     */
    private String toNetscapeHeaderString() {
        StringBuilder sb = new StringBuilder();

        sb.append(getName() + "=" + getValue());

        return sb.toString();
    }

    /*
     * Constructs a string representation of this cookie. The string format is
     * as RFC 2965/2109, but without leading "Cookie:" token.
     */
    private String toRFC2965HeaderString() {
        StringBuilder sb = new StringBuilder();

        sb.append(getName()).append("=\"").append(getValue()).append('"');
        if (getPath() != null)
            sb.append(";$Path=\"").append(getPath()).append('"');
        if (getDomain() != null)
            sb.append(";$Domain=\"").append(getDomain()).append('"');
        if (getPortlist() != null)
            sb.append(";$Port=\"").append(getPortlist()).append('"');

        return sb.toString();
    }

    /*
     * @param dateString        a date string in format of
     *                          "EEE',' dd-MMM-yyyy HH:mm:ss 'GMT'",
     *                          which defined in Netscape cookie spec
     *
     * @return                  delta seconds between this cookie's creation
     *                          time and the time specified by dateString
     */
    private long expiryDate2DeltaSeconds(String dateString) {
        SimpleDateFormat df = new SimpleDateFormat(NETSCAPE_COOKIE_DATE_FORMAT);
        df.setTimeZone(TimeZone.getTimeZone("GMT"));

        try {
            Date date = df.parse(dateString);
            return (date.getTime() - whenCreated) / 1000;
        } catch (Exception e) {
            return 0;
        }
    }


    /*
     * try to guess the cookie version through set-cookie header string
     */
    private static int guessCookieVersion(String header) {
        int version = 0;

        header = header.toLowerCase();
        if (header.indexOf("expires=") != -1) {
            // only netscape cookie using 'expires'
            version = 0;
        } else if (header.indexOf("version=") != -1) {
            // version is mandatory for rfc 2965/2109 cookie
            version = 1;
        } else if (header.indexOf("max-age") != -1) {
            // rfc 2965/2109 use 'max-age'
            version = 1;
        } else if (startsWithIgnoreCase(header, SET_COOKIE2)) {
            // only rfc 2965 cookie starts with 'set-cookie2'
            version = 1;
        }

        return version;
    }

    private static String stripOffSurroundingQuote(String str) {
        if (str != null && str.length() > 0 &&
            str.charAt(0) == '"' && str.charAt(str.length() - 1) == '"') {
            return str.substring(1, str.length() - 1);
        } else {
            return str;
        }
    }

    private static boolean equalsIgnoreCase(String s, String t) {
        if (s == t) return true;
        if ((s != null) && (t != null)) {
            return s.equalsIgnoreCase(t);
        }
        return false;
    }

    private static boolean equals(String s, String t) {
        if (s == t) return true;
        if ((s != null) && (t != null)) {
            return s.equals(t);
        }
        return false;
    }

    private static boolean startsWithIgnoreCase(String s, String start) {
        if (s == null || start == null) return false;

        if (s.length() >= start.length() &&
                start.equalsIgnoreCase(s.substring(0, start.length()))) {
            return true;
        }

        return false;
    }

    /*
     * Split cookie header string according to rfc 2965:
     *   1) split where it is a comma;
     *   2) but not the comma surrounding by double-quotes, which is the comma
     *      inside port list or embeded URIs.
     *
     * @param header            the cookie header string to split
     *
     * @return                  list of strings; never null
     *
     */
    private static List<String> splitMultiCookies(String header) {
        List<String> cookies = new java.util.ArrayList<String>();
        int quoteCount = 0;
        int p, q;

        for (p = 0, q = 0; p < header.length(); p++) {
            char c = header.charAt(p);
            if (c == '"') quoteCount++;
            if (c == ',' && (quoteCount % 2 == 0)) {      // it is comma and not surrounding by double-quotes
                cookies.add(header.substring(q, p));
                q = p + 1;
            }
        }

        cookies.add(header.substring(q));

        return cookies;
    }
}