https://tomcat.apache.org/: jakarta.servlet package 
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */
package jakarta.servlet.http;

import java.io.Serializable;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.text.MessageFormat;
import java.util.BitSet;
import java.util.Locale;
import java.util.ResourceBundle;


Creates a cookie, a small amount of information sent by a servlet to a Web
browser, saved by the browser, and later sent back to the server. A cookie's
value can uniquely identify a client, so cookies are commonly used for
session management.


A cookie has a name, a single value, and optional attributes such as a
comment, path and domain qualifiers, a maximum age, and a version number.
Some Web browsers have bugs in how they handle the optional attributes, so
use them sparingly to improve the interoperability of your servlets.

 The servlet sends cookies to the browser by using the HttpServletResponse.addCookie method, which adds fields to HTTP response headers to send cookies to the browser, one at a time. The browser is expected to support 20 cookies for each Web server, 300 cookies total, and may limit cookie size to 4 KB each. 
 The browser returns cookies to the servlet by adding fields to HTTP request headers. Cookies can be retrieved from a request by using the HttpServletRequest.getCookies method. Several cookies might have the same name but different path attributes. 

Cookies affect the caching of the Web pages that use them. HTTP 1.0 does not
cache pages that use cookies created with this class. This class does not
support the cache control defined with HTTP 1.1.


This class supports both the RFC 2109 and the RFC 6265 specifications.
By default, cookies are created using RFC 6265.

/**
 * Creates a cookie, a small amount of information sent by a servlet to a Web
 * browser, saved by the browser, and later sent back to the server. A cookie's
 * value can uniquely identify a client, so cookies are commonly used for
 * session management.
 * <p>
 * A cookie has a name, a single value, and optional attributes such as a
 * comment, path and domain qualifiers, a maximum age, and a version number.
 * Some Web browsers have bugs in how they handle the optional attributes, so
 * use them sparingly to improve the interoperability of your servlets.
 * <p>
 * The servlet sends cookies to the browser by using the
 * {@link HttpServletResponse#addCookie} method, which adds fields to HTTP
 * response headers to send cookies to the browser, one at a time. The browser
 * is expected to support 20 cookies for each Web server, 300 cookies total, and
 * may limit cookie size to 4 KB each.
 * <p>
 * The browser returns cookies to the servlet by adding fields to HTTP request
 * headers. Cookies can be retrieved from a request by using the
 * {@link HttpServletRequest#getCookies} method. Several cookies might have the
 * same name but different path attributes.
 * <p>
 * Cookies affect the caching of the Web pages that use them. HTTP 1.0 does not
 * cache pages that use cookies created with this class. This class does not
 * support the cache control defined with HTTP 1.1.
 * <p>
 * This class supports both the RFC 2109 and the RFC 6265 specifications.
 * By default, cookies are created using RFC 6265.
 */
public class Cookie implements Cloneable, Serializable {

    private static final CookieNameValidator validation;

    static {
        boolean strictServletCompliance;
        boolean strictNaming;
        boolean allowSlash;
        String propStrictNaming;
        String propFwdSlashIsSeparator;

        if (System.getSecurityManager() == null) {
            strictServletCompliance = Boolean.getBoolean(
                    "org.apache.catalina.STRICT_SERVLET_COMPLIANCE");
            propStrictNaming = System.getProperty(
                    "org.apache.tomcat.util.http.ServerCookie.STRICT_NAMING");
            propFwdSlashIsSeparator = System.getProperty(
                    "org.apache.tomcat.util.http.ServerCookie.FWD_SLASH_IS_SEPARATOR");
        } else {
            strictServletCompliance = AccessController.doPrivileged(
                    (PrivilegedAction<Boolean>) () -> Boolean.valueOf(System.getProperty(
                            "org.apache.catalina.STRICT_SERVLET_COMPLIANCE"))).booleanValue();
            propStrictNaming = AccessController.doPrivileged(
                    (PrivilegedAction<String>) () -> System.getProperty(
                            "org.apache.tomcat.util.http.ServerCookie.STRICT_NAMING"));
            propFwdSlashIsSeparator = AccessController.doPrivileged(
                    (PrivilegedAction<String>) () -> System.getProperty(
                            "org.apache.tomcat.util.http.ServerCookie.FWD_SLASH_IS_SEPARATOR"));
        }

        if (propStrictNaming == null) {
            strictNaming = strictServletCompliance;
        } else {
            strictNaming = Boolean.parseBoolean(propStrictNaming);
        }

        if (propFwdSlashIsSeparator == null) {
            allowSlash = !strictServletCompliance;
        } else {
            allowSlash = !Boolean.parseBoolean(propFwdSlashIsSeparator);
        }

        if (strictNaming) {
            validation = new RFC2109Validator(allowSlash);
        } else {
            validation = new RFC6265Validator();
        }
    }

    private static final long serialVersionUID = 1L;

    private final String name;
    private String value;

    private int version = 0; // ;Version=1 ... means RFC 2109 style

    //
    // Attributes encoded in the header's cookie fields.
    //
    private String comment; // ;Comment=VALUE ... describes cookie's use
    private String domain; // ;Domain=VALUE ... domain that sees cookie
    private int maxAge = -1; // ;Max-Age=VALUE ... cookies auto-expire
    private String path; // ;Path=VALUE ... URLs that see the cookie
    private boolean secure; // ;Secure ... e.g. use SSL
    private boolean httpOnly; // Not in cookie specs, but supported by browsers

    
Constructs a cookie with a specified name and value.


The name must conform to RFC 2109. 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.


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 setValue method.


By default, cookies are created according to the Netscape cookie
specification. The version can be changed with the
setVersion method.

Params:
  • name – 
           a String specifying the name of the cookie
  • value – 
           a String specifying the value of the cookie
Throws:
  • IllegalArgumentException – 
            if the cookie name contains illegal characters (for example,
            a comma, space, or semicolon) or it is one of the tokens
            reserved for use by the cookie protocol
See Also:
/**
     * Constructs a cookie with a specified name and value.
     * <p>
     * The name must conform to RFC 2109. 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 Netscape 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 (for example,
     *             a comma, space, or semicolon) or it is one of the tokens
     *             reserved for use by the cookie protocol
     * @see #setValue
     * @see #setVersion
     */
    public Cookie(String name, String value) {
        validation.validate(name);
        this.name = name;
        this.value = value;
    }

    
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.

Params:
  • purpose – 
           a String specifying the comment to display to the
           user
See Also:
/**
     * 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
null if the cookie has no comment.

See Also:
Returns:a String containing the comment, or
        null if none
/**
     * 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 the domain within which this cookie should be presented.


The form of the domain name is specified by RFC 2109. A domain name
begins with a dot (.foo.com) and means that the cookie is
visible to servers in a specified Domain Name System (DNS) zone (for
example, www.foo.com, but not a.b.foo.com). By
default, cookies are only returned to the server that sent them.

Params:
  • pattern – 
           a String containing the domain name within which
           this cookie is visible; form is according to RFC 2109
See Also:
/**
     * Specifies the domain within which this cookie should be presented.
     * <p>
     * The form of the domain name is specified by RFC 2109. 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 2109
     * @see #getDomain
     */
    public void setDomain(String pattern) {
        domain = pattern.toLowerCase(Locale.ENGLISH); // IE allegedly needs this
    }

    
Returns the domain name set for this cookie. The form of the domain name
is set by RFC 2109.

See Also:
Returns:a String containing the domain name
/**
     * Returns the domain name set for this cookie. The form of the domain name
     * is set by RFC 2109.
     *
     * @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.


A positive value indicates that the cookie will expire after that many
seconds have passed. Note that the value is the maximum age when
the cookie will expire, not the cookie's current age.


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.

Params:
  • expiry – 
           an integer specifying the maximum age of the cookie in
           seconds; if negative, means the cookie is not stored; if zero,
           deletes the cookie
See Also:
/**
     * 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 negative, means the cookie is not stored; if zero,
     *            deletes the cookie
     * @see #getMaxAge
     */
    public void setMaxAge(int expiry) {
        maxAge = expiry;
    }

    
Returns the maximum age of the cookie, specified in seconds, By default,
-1 indicating the cookie will persist until browser
shutdown.

See Also:
Returns:an integer specifying the maximum age of the cookie in seconds; if
        negative, means the cookie persists until browser shutdown
/**
     * 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; if
     *         negative, means the cookie persists until browser shutdown
     * @see #setMaxAge
     */
    public int getMaxAge() {
        return maxAge;
    }

    
Specifies a path for the cookie to which the client should return the
cookie.


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, /catalog,
which makes the cookie visible to all directories on the server under
/catalog.


Consult RFC 2109 (available on the Internet) for more information on
setting path names for cookies.

Params:
  • uri – 
           a String specifying a path
See Also:
/**
     * 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 2109 (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.

See Also:
Returns:a String specifying a path that contains a servlet
        name, for example, /catalog
/**
     * 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.


The default value is false.

Params:
  • flag – 
           if true, sends the cookie from the browser to the
           server only when using a secure protocol; if
           false, sent on any protocol
See Also:
/**
     * 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 only when using a secure protocol; if
     *            <code>false</code>, sent on any protocol
     * @see #getSecure
     */
    public void setSecure(boolean flag) {
        secure = flag;
    }

    
Returns true if the browser is sending cookies only over a
secure protocol, or false if the browser can send cookies
using any protocol.

See Also:
Returns:true if the browser uses a secure protocol;
        otherwise, true
/**
     * 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 uses a secure protocol;
     *         otherwise, <code>true</code>
     * @see #setSecure
     */
    public boolean getSecure() {
        return secure;
    }

    
Returns the name of the cookie. The name cannot be changed after
creation.

Returns:a String specifying the cookie's name
/**
     * 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.


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.

Params:
  • newValue – 
           a String specifying the new value
See Also:
/**
     * 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
     * @see Cookie
     */
    public void setValue(String newValue) {
        value = newValue;
    }

    
Returns the value of the cookie.

See Also:
Returns:a String containing the cookie's present value
/**
     * Returns the value of the cookie.
     *
     * @return a <code>String</code> containing the cookie's present value
     * @see #setValue
     * @see Cookie
     */
    public String getValue() {
        return value;
    }

    
Returns the version of the protocol this cookie complies with. Version 1
complies with RFC 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.

See Also:
Returns:0 if the cookie complies with the original Netscape specification;
        1 if the cookie complies with RFC 2109
/**
     * Returns the version of the protocol this cookie complies with. Version 1
     * complies with RFC 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 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 2109.


Since RFC 2109 is still somewhat new, consider version 1 as experimental;
do not use it yet on production sites.

Params:
  • v – 
           0 if the cookie should comply with the original Netscape
           specification; 1 if the cookie should comply with RFC 2109
See Also:
/**
     * 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 2109.
     * <p>
     * Since RFC 2109 is still somewhat new, consider version 1 as experimental;
     * do not use it yet on production sites.
     *
     * @param v
     *            0 if the cookie should comply with the original Netscape
     *            specification; 1 if the cookie should comply with RFC 2109
     * @see #getVersion
     */
    public void setVersion(int v) {
        version = v;
    }

    
Overrides the standard java.lang.Object.clone method to
return a copy of this cookie.

/**
     * Overrides the standard <code>java.lang.Object.clone</code> method to
     * return a copy of this cookie.
     */
    @Override
    public Object clone() {
        try {
            return super.clone();
        } catch (CloneNotSupportedException e) {
            throw new RuntimeException(e);
        }
    }

    
Sets the flag that controls if this cookie will be hidden from scripts on
the client side.

Params:
  • httpOnly –  The new value of the flag
Since:Servlet 3.0
/**
     * Sets the flag that controls if this cookie will be hidden from scripts on
     * the client side.
     *
     * @param httpOnly  The new value of the flag
     *
     * @since Servlet 3.0
     */
    public void setHttpOnly(boolean httpOnly) {
        this.httpOnly = httpOnly;
    }

    
Gets the flag that controls if this cookie will be hidden from scripts on
the client side.

Returns: true if the cookie is hidden from scripts, else
         false
Since:Servlet 3.0
/**
     * Gets the flag that controls if this cookie will be hidden from scripts on
     * the client side.
     *
     * @return  <code>true</code> if the cookie is hidden from scripts, else
     *          <code>false</code>
     * @since Servlet 3.0
     */
    public boolean isHttpOnly() {
        return httpOnly;
    }
}


class CookieNameValidator {
    private static final String LSTRING_FILE = "jakarta.servlet.http.LocalStrings";
    protected static final ResourceBundle lStrings = ResourceBundle.getBundle(LSTRING_FILE);

    protected final BitSet allowed;

    protected CookieNameValidator(String separators) {
        allowed = new BitSet(128);
        allowed.set(0x20, 0x7f); // any CHAR except CTLs or separators
        for (int i = 0; i < separators.length(); i++) {
            char ch = separators.charAt(i);
            allowed.clear(ch);
        }
    }

    void validate(String name) {
        if (name == null || name.length() == 0) {
            throw new IllegalArgumentException(lStrings.getString("err.cookie_name_blank"));
        }
        if (!isToken(name)) {
            String errMsg = lStrings.getString("err.cookie_name_is_token");
            throw new IllegalArgumentException(MessageFormat.format(errMsg, name));
        }
    }

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

        for (int i = 0; i < len; i++) {
            char c = possibleToken.charAt(i);
            if (!allowed.get(c)) {
                return false;
            }
        }
        return true;
    }
}

class RFC6265Validator extends CookieNameValidator {
    private static final String RFC2616_SEPARATORS = "()<>@,;:\\\"/[]?={} \t";

    RFC6265Validator() {
        super(RFC2616_SEPARATORS);
    }
}

class RFC2109Validator extends RFC6265Validator {
    RFC2109Validator(boolean allowSlash) {
        // special treatment to allow for FWD_SLASH_IS_SEPARATOR property
        if (allowSlash) {
            allowed.set('/');
        }
    }

    @Override
    void validate(String name) {
        super.validate(name);
        if (name.charAt(0) == '$') {
            String errMsg = lStrings.getString("err.cookie_name_is_token");
            throw new IllegalArgumentException(MessageFormat.format(errMsg, name));
        }
    }
}