javax.servlet.http.HttpSession Maven / Gradle / Ivy
/*
* Copyright (c) 1997-2018 Oracle and/or its affiliates. All rights reserved.
* 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.util.Enumeration;
import javax.servlet.ServletContext;
/**
*
* Provides a way to identify a user across more than one page
* request or visit to a Web site 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
*
- 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
* {@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 invalidated or expired.
*
*
When container migrates a session between VMs in a distributed container
* setting, all session attributes 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
*
* @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
*/
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 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.
*
* @return a long
* representing the last time
* the client sent a request associated
* with this session, expressed in
* milliseconds since 1/1/1970 GMT
*
* @exception 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 Servlet 2.3
*/
public ServletContext getServletContext();
/**
* Specifies the time, in seconds, between client requests before the
* servlet container will invalidate this session.
*
*
An interval value of zero or less indicates that 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 return value of zero or less indicates that the
* session will 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.
*
* @return the {@link HttpSessionContext} for this session.
*/
@Deprecated
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
*/
@Deprecated
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
*/
@Deprecated
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
* 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
*/
@Deprecated
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.
*
*
After this method executes, and if the object
* implements 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
*/
@Deprecated
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();
}