javax.servlet.http.HttpSession Maven / Gradle / Ivy
/*
* 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.
*
* @see HttpSessionBindingListener
*/
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
* @exception 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 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. A zero or negative time
* 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 zero or negative time indicates that 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();
/**
* Do not use.
* @return A dummy implementation of HttpSessionContext
* @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.
*/
@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);
/**
* @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 As of Version 2.2, this method is replaced by
* {@link #getAttribute}.
*/
@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();
/**
* @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 As of Version 2.2, this method is replaced by
* {@link #getAttributeNames}
*/
@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);
/**
* @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 As of Version 2.2, this method is replaced by
* {@link #setAttribute}
*/
@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);
/**
* @param name
* the name of the object to remove from this session
* @exception IllegalStateException
* if this method is called on an invalidated session
* @deprecated As of Version 2.2, this method is replaced by
* {@link #removeAttribute}
*/
@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();
}