// HttpSession - an association of HTTP interactions//// API based on documentation from JavaSoft.//// Copyright (C) 1998 by Jef Poskanzer <jef@acme.com>. All rights reserved.//// Redistribution and use in source and binary forms, with or without// modification, are permitted provided that the following conditions// are met:// 1. Redistributions of source code must retain the above copyright//    notice, this list of conditions and the following disclaimer.// 2. Redistributions in binary form must reproduce the above copyright//    notice, this list of conditions and the following disclaimer in the//    documentation and/or other materials provided with the distribution.//// THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE// ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS// OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF// SUCH DAMAGE.//// Visit the ACME Labs Java page for up-to-date versions of this and other// fine Java utilities: http://www.acme.com/java/package Acme.Serve.servlet.http;import Acme.Serve.servlet.*;/// An association of HTTP interactions.// <P>// This is taken from JavaSoft's Servlet API documentation.// <P>// <A HREF="/resources/classes/Acme/Serve/servlet/http/HttpSession.java">Fetch the software.</A><BR>// <A HREF="/resources/classes/Acme.tar.gz">Fetch the entire Acme package.</A>public interface HttpSession    {    /// Returns the identifier assigned to this session.  An HttpSession's    // identifier is a unique string that is created and maintained by    // HttpSessionContext.    public String getId();    /// Returns the context in which this session is bound.    public HttpSessionContext getSessionContext();    /// Returns the time at which this session representation was created.    public long getCreationTime();    /// Returns the last time the client sent a request carrying the identifier    // assigned to the session.  Application level operations, such as getting    // or setting a value associated with the session, does not affect the    // access time.    // <P>    // This information is particularly useful in session management policies.    // For example, a session manager could leave all sessions which have not    // been used in a long time in a given context.  The sessions can be    // sorted according to age to optimize some task.    public long getLastAccessedTime();    /// Causes this representation of the session to be invalidated and removed    // from its context.    // @exception IllegalStateException if an attempt is made to access session data after the session has been invalidated    public void invalidate();    /// Binds the specified object into the session's application layer data    // with the given name.  Any existing binding with the same name is    // replaced.  New (or existing) values that implement the    // HttpSessionBindingListener interface will call its valueBound()    // method.    public void putValue( String name, Object value );    /// Returns the object bound to the given name in the session's application    // layer data.  Returns null if there is no such binding.    public Object getValue( String name );    /// Removes the object bound to the given name in the session's application    // layer data.  Does nothing if there is no object bound to the given name.    // The value that implements the HttpSessionBindingListener interface will    // call its valueUnbound() method.    public void removeValue( String name );    /// Returns an array of the names of all the application layer data objects    // bound into the session.  For example, if you want to delete all of the    // data objects bound into the session, use this method to obtain their    // names.    // public String[] getValueNames();    /// A session is considered to be "new" if it has been created by the    // server, but the client has not yet acknowledged joining the session.    // For example, if the server supported only cookie-based sessions and the    // client had completely disabled the use of cookies, then calls to    // HttpServletRequest.getSession() would always return "new" sessions.    public boolean isNew();    }