// Topic - a conferencing 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;

import java.util.*;

/// A conferencing topic.
// <P>
// Topics are contained in conferences, and contain responses.
// Each topic has a title, and flags saying whether it's retired or frozen.
// <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/Topic.java">Fetch the software.</A><BR>
// <A HREF="/resources/classes/Acme.tar.gz">Fetch the entire Acme package.</A>
// <P>
// @see Conference
// @see Response

public abstract class Topic
    {

    /// The date this topic was created.
    public abstract long getDate();

    /// The user who created this topic
    public abstract User getCreator();
    
    /// The topic's title.
    public abstract String getTitle();
    
    /// The last response number.  Response numbers always start at
    // zero and there are no gaps.
    public abstract int getLastResponseNumber();

    /// Get a response by number.
    public abstract Response getResponse( int n );
    
    /// Whether the topic is retired.
    // Retired topics are generally not shown.
    public abstract boolean isRetired();

    /// Whether the topic is frozen.
    // Frozen topics may not have new responses added.
    public abstract boolean isFrozen();


    /// Retire this topic.
    // <P>
    // Only a host or the topic creator may do this.
    public abstract void retire( Session session );

    /// Unretire this topic.
    // <P>
    // Only a host or the topic creator may do this.
    public abstract void unretire( Session session );

    /// Freeze this topic.
    // <P>
    // Only a host or the topic creator may do this.
    public abstract void freeze( Session session );

    /// Unfreeze this topic.
    // <P>
    // Only a host or the topic creator may do this.
    public abstract void unfreeze( Session session );

    /// Add a new response to the topic.
    // If the pseud is null then the user's real name is used.
    // <P>
    // Note that there is no method for linking an existing response.
    // Unlike topics, which can be in multiple conferences, responses
    // can be in only one topic.
    public abstract int addResponse( Session session, String pseud, String text );

    }