/*
   * Copyright 2004 The Apache Software Foundation
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
  package javax.servlet.http;
  
  import java.text.MessageFormat;
  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.
   * 
   * <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
   * @version	$Version$
   *
   */
  
  // XXX would implement java.io.Serializable too, but can't do that
  // so long as sun.servlet.* must run on older JDK 1.02 JVMs which
  // don't include that support.
  
  public class Cookie implements Cloneable {
  
      private static final String LSTRING_FILE =
  	"javax.servlet.http.LocalStrings";
      private static ResourceBundle lStrings =
  	ResourceBundle.getBundle(LSTRING_FILE);
      
      //
      // 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
      
      
  
      /**
       * 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) {
 	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.
      *
      * @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 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();	// IE allegedly needs this
     }
     
     
     
     
 
     /**
      * 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.
      *
      * <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, <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.
      *
      * <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.
      *
      *
      * @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 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 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.
      *
      * @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
      * @see Cookie
      *
      */
 
     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
      * @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.
      * 
      *
      * @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.
      *
      * <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;
     }
 
     // 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 
      * 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>
      *				if it is not			
      */
 
     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 <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());
 	}
     }
 }