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 *
When an application stores an object in or removes an object from a * session, the session checks whether the object implements * {@link 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 session that are invalidated or expire, notifications are sent after * the session has been invalidatd or expired. * *
When container migrates a session between VMs in a distributed container * setting, all session atributes implementing the {@link HttpSessionActivationListener} * interface 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
* (ServletContext), so information stored in one context
* will not be directly visible in another.
*
* @author Various
* @version $Version$
*
*
* @see HttpSessionBindingListener
* @see HttpSessionContext
*
*/
public interface HttpSession {
/**
*
* Returns the time when this session was created, measured
* in milliseconds since midnight January 1, 1970 GMT.
*
* @return a long specifying
* when this session was created,
* expressed in
* milliseconds since 1/1/1970 GMT
*
* @exception IllegalStateException if this method is called on an
* invalidated session
*
*/
public long getCreationTime();
/**
*
* Returns a string containing the unique identifier assigned
* to this session. The identifier is assigned
* by the servlet container and is implementation dependent.
*
* @return a string specifying the identifier
* assigned to this session
*
* @exeption IllegalStateException if this method is called on an
* invalidated session
*
*/
public String getId();
/**
*
* Returns the last time the client sent a request associated with
* this session, as the number of milliseconds since midnight
* January 1, 1970 GMT, and marked by the time the container recieved the request.
*
*
Actions that your application takes, such as getting or setting
* a value associated with the session, do not affect the access
* time.
*
* @return a long
* representing the last time
* the client sent a request associated
* with this session, expressed in
* milliseconds since 1/1/1970 GMT
*
* @exeption IllegalStateException if this method is called on an
* invalidated session
*
*/
public long getLastAccessedTime();
/**
* Returns the ServletContext to which this session belongs.
*
* @return The ServletContext object for the web application
* @since 2.3
*/
public ServletContext getServletContext();
/**
*
* Specifies the time, in seconds, between client requests before the
* servlet container will invalidate this session. A negative time
* indicates the session should never timeout.
*
* @param interval An integer specifying the number
* of seconds
*
*/
public void setMaxInactiveInterval(int interval);
/**
* 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 the setMaxInactiveInterval method.
* A negative time indicates the session should never timeout.
*
*
* @return an integer specifying the number of
* seconds this session remains open
* between client requests
*
* @see #setMaxInactiveInterval
*
*
*/
public int getMaxInactiveInterval();
/**
*
* @deprecated As of Version 2.1, this method is
* deprecated and has no replacement.
* It will be removed in a future
* version of the Java Servlet API.
*
*/
public HttpSessionContext getSessionContext();
/**
*
* Returns the object bound with the specified name in this session, or
* null if no object is bound under the name.
*
* @param name a string specifying the name of the object
*
* @return the object with the specified name
*
* @exception IllegalStateException if this method is called on an
* invalidated session
*
*/
public Object getAttribute(String name);
/**
*
* @deprecated As of Version 2.2, this method is
* replaced by {@link #getAttribute}.
*
* @param name a string specifying the name of the object
*
* @return the object with the specified name
*
* @exception IllegalStateException if this method is called on an
* invalidated session
*
*/
public Object getValue(String name);
/**
*
* Returns an Enumeration of String objects
* containing the names of all the objects bound to this session.
*
* @return an Enumeration of
* String objects specifying the
* names of all the objects bound to
* this session
*
* @exception IllegalStateException if this method is called on an
* invalidated session
*
*/
public Enumeration getAttributeNames();
/**
*
* @deprecated As of Version 2.2, this method is
* replaced by {@link #getAttributeNames}
*
* @return an array of String
* objects specifying the
* names of all the objects bound to
* this session
*
* @exception IllegalStateException if this method is called on an
* invalidated session
*
*/
public String[] getValueNames();
/**
* Binds an object to this session, using the name specified.
* 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 HttpSessionBindingListener,
* the container calls
* HttpSessionBindingListener.valueBound. The container then
* notifies any HttpSessionAttributeListeners in the web
* application.
*
If an object was already bound to this session of this name
* that implements HttpSessionBindingListener, its
* HttpSessionBindingListener.valueUnbound method is called.
*
*
If the value passed in is null, this has the same effect as calling
* After this method executes, and if the object
* implements removeAttribute().
*
*
* @param name the name to which the object is bound;
* cannot be null
*
* @param value the object to be bound
*
* @exception IllegalStateException if this method is called on an
* invalidated session
*
*/
public void setAttribute(String name, Object value);
/**
*
* @deprecated As of Version 2.2, this method is
* replaced by {@link #setAttribute}
*
* @param name the name to which the object is bound;
* cannot be null
*
* @param value the object to be bound; cannot be null
*
* @exception IllegalStateException if this method is called on an
* invalidated session
*
*/
public void putValue(String name, Object value);
/**
*
* 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.
*
* HttpSessionBindingListener,
* the container calls
* HttpSessionBindingListener.valueUnbound. The container
* then notifies any HttpSessionAttributeListeners in the web
* application.
*
*
*
* @param name the name of the object to
* remove from this session
*
* @exception IllegalStateException if this method is called on an
* invalidated session
*/
public void removeAttribute(String name);
/**
*
* @deprecated As of Version 2.2, this method is
* replaced by {@link #removeAttribute}
*
* @param name the name of the object to
* remove from this session
*
* @exception IllegalStateException if this method is called on an
* invalidated session
*/
public void removeValue(String name);
/**
*
* Invalidates this session then unbinds any objects bound
* to it.
*
* @exception IllegalStateException if this method is called on an
* already invalidated session
*
*/
public void invalidate();
/**
*
* Returns true if 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.
*
* @return true if the
* server has created a session,
* but the client has not yet joined
*
* @exception IllegalStateException if this method is called on an
* already invalidated session
*
*/
public boolean isNew();
}