NAME

Servlet::Http::HttpSession - HTTP session interface

SYNOPSIS

  for my $name ($session->getAttributeNames()) {
      my $value = $session->getAttribute($name);
      # or
      $session->removeAttribute($name);
  }

  my $time = $session->getCreationTime();

  my $id = $session->getId();

  my $time = $session->getLastAccessedTime();

  my $timeout = $session->getMaxInactiveInterval();

  $session->invalidate();

  my $bool = $session->isNew();

  $session->setAttributre($name, $value);

  $session->setMaxInactiveInterval($timeout);

DESCRIPTION

Provides a way to identify a user across more than one page request or site visit and to store information about that user.

The servlet container uses this interface to create a session between an HTTP client and an HTTP server. The session persists for a specified time period, across more than one connection or page request from the user. A session usually corresponds to one user, who may visit a site many times. The server can maintain a session in many ways such as using cookies or rewriting URLs.

This interface allows servlets to view and manipulate information about a session, such as the session identifier, creation time and last accessed time, and to bind objects to sessions, allowing user information to persist across multiple user connections.

When an application stores an object in or removes an object from a session, the session checks whether the object implements Servlet::Http::HttpSessionBindingListener. If it does, the servlet notifies the object that it has been bound to or unbound from the session. Notifications are sent after the binding methods complete. For sessions that are invalidated or expire, notifications are sent after the session has been invalidated or expired.

When a container migrates a session between intepreters in a distributed container setting, all session attributes implementing Servlet::Http::HttpSessionActivationListener are notified.

A servlet should be able to handle cases in which the client does not choose to join a session, such as when cookies are intentionally turned off. Until the client joins the session, isNew() returns true. If the client chooses not to join the session, getSession() will return a different session on each request, and isNew() will always return true.

Session information is scoped only to the current web application (Servlet::ServletContext), so information stored in one context will not be directly visible in another.

METHODS

getAttribute($name)

Returns the object bound with the specified name in this session, or undef if no object is bound under the name.

Parameters:

$name

the name of the object

Throws:

Servlet::Util::IllegalStateException

if this method is called on an invalidated session

getAttributeNames()

Returns an array containing the names of all the objects bound to this session, or an empty array if there are no bound objects.

Throws:

Servlet::Util::IllegalStateException

if this method is called on an invalidated session

getCreationTime()

Returns the time when this session was created, measured in seconds since the epoch.

Throws:

Servlet::Util::IllegalStateException

if this method is called on an invalidated session

getId()

Returns the unique identifier assigned to this session. The identifier is assigned by the servlet container and is implementation dependent.

getLastAccessedTime()

Returns the last time the client sent a request associated with this session, as the number of seconds since the epoch, and marked by the time the container received the request.

Actions that your application takes, such as getting or setting a value associated with the session, do not affect the access time.

getMaxInactiveInterval()

Returns the maximum time interval (in seconds) that the servlet container will keep this session open between client accesses. After this interval, the servlet container will invalidate the session. The maximum time interval can be set with setMaxInactiveInterval(). A negative time indicates the session should never time out.

invalidate()

Invalidates this session, then unbinds any objects bound to it.

Throws:

Servlet::Util::IllegalStateException

if this method is called on an invalidated session

isNew()

Returns true fi the client does not yet know about the session or if the client chooses not to join the session. For example, if the server used only cookie-based sessions, and the client had disabled the use of cookies, then a session would be new on each request.

Throws:

Servlet::Util::IllegalStateException

if this method is called on an invalidated session

removeAttribute($name)

Removes the object bound with the specified name from this session. If the session does not have an object bound with the specified name, this method does nothing.

After this method executes, and if the object implements Servlet::Http::HttpSessionBindingListener, the container calls valueUnbound() on the object.

Parameters:

$name

the name of the object

Throws:

Servlet::Util::IllegalStateException

if this method is called on an invalidated session

setAttribute($name, $value)

Binds an object to this session using the specified name. If an object of the same name is already bound to the session, the object is replaced.

After this method executes, and if the new object implements Servlet::Http::HttpSessionBindingListener, the container calls valueBound() on the object.

If a previously bound object was replaced, and it implements Servlet::Http::HttpSessionBindingListener, the container calls valueUnbound() on it.

Parameters:

$name

the name to which the object is bound

$value

the object to be bound

Throws:

Servlet::Util::IllegalStateException

if this method is called on an invalidated session

setMaxInactiveInterval($interval)

Specifies the time, in seconds, between client requests before the servlet container will invalidate this session. A negative indicates the session should never timeout.

Parameters:

$interval

the number of seconds

SEE ALSO

Servlet::Http::HttpSessionActivationListener, Servlet::Http::HttpSessionBindingListener, Servlet::Http::HttpSessionContext

AUTHOR

Brian Moseley, bcm@maz.org