http://www.jboss.org/jboss-servlet-api_4.0_spec: The Java Servlet 4.0 API classes (JBoss by Red Hat) 
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package javax.servlet.http;

import java.io.Serializable;
import java.text.MessageFormat;
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 Version 0 (by Netscape) and Version 1 
(by RFC 2109) cookie specifications. By default, cookies are
created using Version 0 to ensure the best interoperability.

Author:	Various
/**
 *
 * 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 Version 0 (by Netscape) and Version 1 
 * (by RFC 2109) cookie specifications. By default, cookies are
 * created using Version 0 to ensure the best interoperability.
 *
 * @author	Various
 */
public class Cookie implements Cloneable, Serializable {

    private static final long serialVersionUID = -6454587001725327448L;

    private static final String TSPECIALS;

    private static final String LSTRING_FILE =
        "javax.servlet.http.LocalStrings";

    private static ResourceBundle lStrings =
        ResourceBundle.getBundle(LSTRING_FILE);

    static {
        if (Boolean.valueOf(System.getProperty("org.glassfish.web.rfc2109_cookie_names_enforced", "true"))) {
            TSPECIALS = "/()<>@,;:\\\"[]?={} \t";
        } else {
            TSPECIALS = ",; ";
        }
    }
    
    //
    // 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
				// ;Discard ... implied by maxAge < 0
    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 int version = 0;	// ;Version=1 ... means RFC 2109++ style
    private boolean isHttpOnly = false;

    
Constructs a cookie with the specified name and value.

The name must conform to RFC 2109. However, vendors may
provide a configuration option that allows cookie names conforming
to the original Netscape Cookie Specification to be accepted.

The name of a cookie cannot be changed once the cookie has
been created.

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 – the name of the cookie
  • value – the value of the cookie
Throws:
  • IllegalArgumentException – 	if the cookie name is null or
empty or contains any illegal characters (for example, a comma,
space, or semicolon) or matches a token reserved for use by the
cookie protocol
See Also:
/**
     * Constructs a cookie with the specified name and value.
     *
     * <p>The name must conform to RFC 2109. However, vendors may
     * provide a configuration option that allows cookie names conforming
     * to the original Netscape Cookie Specification to be accepted.
     *
     * <p>The name of a cookie cannot be changed once the cookie has
     * been created.
     *
     * <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 the name of the cookie
     *
     * @param value the value of the cookie
     *
     * @throws IllegalArgumentException	if the cookie name is null or
     * empty or contains any illegal characters (for example, a comma,
     * space, or semicolon) or matches a token reserved for use by the
     * cookie protocol
     *
     * @see #setValue
     * @see #setVersion
     */
    public Cookie(String name, String value) {
        if (name == null || name.length() == 0) {
            throw new IllegalArgumentException(
                    lStrings.getString("err.cookie_name_blank"));
        }
        if (!isToken(name) ||
                name.equalsIgnoreCase("Comment") || // rfc2019
                name.equalsIgnoreCase("Discard") || // 2019++
                name.equalsIgnoreCase("Domain") ||
                name.equalsIgnoreCase("Expires") || // (old cookies)
                name.equalsIgnoreCase("Max-Age") || // rfc2019
                name.equalsIgnoreCase("Path") ||
                name.equalsIgnoreCase("Secure") ||
                name.equalsIgnoreCase("Version") ||
                name.startsWith("$")) {
            String errMsg = lStrings.getString("err.cookie_name_is_token");
            Object[] errArgs = new Object[1];
            errArgs[0] = name;
            errMsg = MessageFormat.format(errMsg, errArgs);
            throw new IllegalArgumentException(errMsg);
        }

        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:the comment of the cookie, or null if unspecified
/**
     * Returns the comment describing the purpose of this cookie, or
     * <code>null</code> if the cookie has no comment.
     *
     * @return the comment of the cookie, or <code>null</code> if unspecified
     *
     * @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:
  • domain – 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 domain the domain name within which this cookie is visible;
     * form is according to RFC 2109
     *
     * @see #getDomain
     */
    public void setDomain(String domain) {
        this.domain = domain.toLowerCase(Locale.ENGLISH); // IE allegedly needs this
    }

    
Gets the domain name of this Cookie.

Domain names are formatted according to RFC 2109.

See Also:
Returns:the domain name of this Cookie
/**
     * Gets the domain name of this Cookie.
     *
     * <p>Domain names are formatted according to RFC 2109.
     *
     * @return the domain name of this Cookie
     *
     * @see #setDomain
     */ 
    public String getDomain() {
        return domain;
    }

    
Sets the maximum age in seconds for this Cookie.

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 in seconds for this Cookie.
     *
     * <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;
    }

    
Gets the maximum age in seconds of this Cookie.

By default, -1 is returned, which indicates that
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
/**
     * Gets the maximum age in seconds of this Cookie.
     *
     * <p>By default, <code>-1</code> is returned, which indicates that
     * 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,
false otherwise
/**
     * 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,
     * <code>false</code> otherwise
     *
     * @see #setSecure
     */
    public boolean getSecure() {
        return secure;
    }

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

Returns:the name of the cookie
/**
     * Returns the name of the cookie. The name cannot be changed after
     * creation.
     *
     * @return the name of the cookie
     */
    public String getName() {
        return name;
    }

    
Assigns a new value to this Cookie.

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 – the new value of the cookie
See Also:
/**
     * Assigns a new value to this Cookie.
     * 
     * <p>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 the new value of the cookie
     *
     * @see #getValue
     */
    public void setValue(String newValue) {
        value = newValue;
    }

    
Gets the current value of this Cookie.

See Also:
Returns:the current value of this Cookie
/**
     * Gets the current value of this Cookie.
     *
     * @return the current value of this Cookie
     *
     * @see #setValue
     */
    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 that 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 that this Cookie complies
     * with.
     *
     * <p>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;
    }

    /*
     * Tests a string and returns true if the string counts as a 
     * reserved token in the Java language.
     * 
     * @param value the <code>String</code> to be tested
     *
     * @return <code>true</code> if the <code>String</code> is a reserved
     * token; <code>false</code> otherwise
     */
    private 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;
    }

    
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.
     */
    public Object clone() {
        try {
            return super.clone();
        } catch (CloneNotSupportedException e) {
            throw new RuntimeException(e.getMessage());
        }
    }

    
Marks or unmarks this Cookie as HttpOnly.

If isHttpOnly is set to true, this cookie is
marked as HttpOnly, by adding the HttpOnly attribute
to it.

HttpOnly cookies are not supposed to be exposed to
client-side scripting code, and may therefore help mitigate certain
kinds of cross-site scripting attacks.

Params:
  • isHttpOnly – true if this cookie is to be marked as
HttpOnly, false otherwise
Since:Servlet 3.0
/**
     * Marks or unmarks this Cookie as <i>HttpOnly</i>.
     *
     * <p>If <tt>isHttpOnly</tt> is set to <tt>true</tt>, this cookie is
     * marked as <i>HttpOnly</i>, by adding the <tt>HttpOnly</tt> attribute
     * to it.
     *
     * <p><i>HttpOnly</i> cookies are not supposed to be exposed to
     * client-side scripting code, and may therefore help mitigate certain
     * kinds of cross-site scripting attacks.
     *
     * @param isHttpOnly true if this cookie is to be marked as
     * <i>HttpOnly</i>, false otherwise
     *
     * @since Servlet 3.0
     */
    public void setHttpOnly(boolean isHttpOnly) {
        this.isHttpOnly = isHttpOnly;
    }
 
    
Checks whether this Cookie has been marked as HttpOnly.

Returns:true if this Cookie has been marked as HttpOnly,
false otherwise
Since:Servlet 3.0
/**
     * Checks whether this Cookie has been marked as <i>HttpOnly</i>.
     *
     * @return true if this Cookie has been marked as <i>HttpOnly</i>,
     * false otherwise
     *
     * @since Servlet 3.0
     */
    public boolean isHttpOnly() {
        return isHttpOnly;
    }
}