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184

Chapter 8 Handling Cookies

getVersion

 and 

setVersion

), the comment is used purely for 

informational purposes on the server; it is not sent to the client.

public String getDomain()

public void setDomain(String domainPattern)

These methods get or set the domain to which the cookie applies. 

Normally, the browser only returns cookies to the exact same host 

name that sent them. You can use 

setDomain

 method to instruct the 

browser to return them to other hosts within the same domain. To 

prevent servers setting cookies that apply to hosts outside their 

domain, the domain specified is required to start with a dot (e.g., 

.prenhall.com

), and must contain two dots for noncountry domains 

like 

.com

, 

.edu

 and 

.gov

; and three dots for country domains like 

.co.uk

 and 

.edu.es

. For instance, cookies sent from a servlet at 

bali.vacations.com

 would not normally get sent by the browser to 

pages at 

mexico.vacations.com

. If the site wanted this to happen, 

the servlets could specify 

cookie.setDomain(".vacations.com")

. 

public int getMaxAge()

public void setMaxAge(int lifetime)

These methods tell how much time (in seconds) should elapse before 

the cookie expires. A negative value, which is the default, indicates that 

the cookie will last only for the current session (i.e., until the user quits 

the browser) and will not be stored on disk. See the 

LongLivedCookie

class (Listing 8.4), which defines a subclass of 

Cookie

 with a maximum 

age automatically set one year in the future. Specifying a value of 0 

instructs the browser to delete the cookie. 

public String getName()

public void setName(String cookieName)

This pair of methods gets or sets the name of the cookie. The name and 

the value are the two pieces you virtually always care about. However, 

since the name is supplied to the 

Cookie

 constructor, you rarely need to 

call 

setName

. On the other hand, 

getName

 is used on almost every 

cookie received on the server. Since the 

getCookies

 method of 

Http 

ServletRequest

 returns an array of 

Cookie

 objects, it is common to 

loop down this array, calling 

getName

 until you have a particular name, 

then check the value with 

getValue

. For an encapsulation of this pro 

cess, see the 

getCookieValue

 method shown in Listing 8.3.

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