javax.servlet.http.HttpSession Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*
* @version $Rev: 788194 $ $Date: 2009-06-24 18:05:48 -0400 (Wed, 24 Jun 2009) $
* @see HttpSessionBindingListener
* @see HttpSessionContext
*/
public interface HttpSession {
/**
* Returns the time when this session was created, measured
* in milliseconds since midnight January 1, 1970 GMT.
*
* @throws IllegalStateException if this method is called on an
* invalidated session
* @return a long specifying
* when this session was created,
* expressed in
* milliseconds since 1/1/1970 GMT
*/
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.
*
* @throws IllegalStateException if this method is called on an
* invalidated session
* @return a string specifying the identifier
* assigned to this session
*/
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.
*
* @throws IllegalStateException if this method is called on an
* invalidated session
* @return a long
* representing the last time
* the client sent a request associated
* with this session, expressed in
* milliseconds since 1/1/1970 GMT
*/
long getLastAccessedTime();
/**
* Returns the ServletContext to which this session belongs.
*
* @return The ServletContext object for the web application
* @since 2.3
*/
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
*/
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
*/
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.
*/
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
* @throws IllegalStateException if this method is called on an
* invalidated session
* @return the object with the specified name
*/
Object getAttribute(String name);
/**
* @param name a string specifying the name of the object
* @throws IllegalStateException if this method is called on an
* invalidated session
* @return the object with the specified name
* @deprecated As of Version 2.2, this method is
* replaced by {@link #getAttribute}.
*/
Object getValue(String name);
/**
* Returns an Enumeration of String objects
* containing the names of all the objects bound to this session.
*
* @throws IllegalStateException if this method is called on an
* invalidated session
* @return an Enumeration of
* String objects specifying the
* names of all the objects bound to
* this session
*/
Enumeration getAttributeNames();
/**
* @throws IllegalStateException if this method is called on an
* invalidated session
* @return an array of String
* objects specifying the
* names of all the objects bound to
* this session
* @deprecated As of Version 2.2, this method is
* replaced by {@link #getAttributeNames}
*/
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
* @throws IllegalStateException if this method is called on an
* invalidated session
*/
void setAttribute(String name, Object value);
/**
* @param name the name to which the object is bound;
* cannot be null
* @param value the object to be bound; cannot be null
* @throws IllegalStateException if this method is called on an
* invalidated session
* @deprecated As of Version 2.2, this method is
* replaced by {@link #setAttribute}
*/
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
* @throws IllegalStateException if this method is called on an
* invalidated session
*/
void removeAttribute(String name);
/**
* @param name the name of the object to
* remove from this session
* @throws IllegalStateException if this method is called on an
* invalidated session
* @deprecated As of Version 2.2, this method is
* replaced by {@link #removeAttribute}
*/
void removeValue(String name);
/**
* Invalidates this session then unbinds any objects bound
* to it.
*
* @throws IllegalStateException if this method is called on an
* already invalidated session
*/
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
* @throws IllegalStateException if this method is called on an
* already invalidated session
*/
boolean isNew();
}