// Seen - what responses a user has seen in a topic
//
// Copyright (C) 1996 by Jef Poskanzer <jef@mail.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.Conf;

/// What responses a user has seen in a topic.
// <P>
// Users have one of these for each topic they are reading.
// They are stored in a Seentab.
// <P>
// This is an abstract class with separate implementations on the
// client and server sides, mirrored via RPC.
// <P>
// <A HREF="/resources/classes/Acme/Conf/Seen.java">Fetch the software.</A><BR>
// <A HREF="/resources/classes/Acme.tar.gz">Fetch the entire Acme package.</A>
// <P>
// @see User
// @see Topic
// @see Seentab

public abstract class Seen
    {

    /// Whether the topic is forgotten.
    public abstract boolean isForgotten();

    /// The last response number the user has read.
    public abstract int getLastResponseNumberSeen();


    /// Forget the topic.
    public abstract void forget( Session session );

    /// Remember the topic.
    public abstract void unforget( Session session );

    /// Set the last response number read.
    public abstract void setLastResponseNumberSeen( Session session, int n );

    }