001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License.
018 *
019 */
020package org.apache.mina.filter.keepalive;
021
022import org.apache.mina.core.session.IoSession;
023
024/**
025 * Provides keep-alive messages to {@link KeepAliveFilter}.
026 *  
027 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
028 */
029public interface KeepAliveMessageFactory {
030
031    /**
032     * @return <tt>true</tt> if and only if the specified message is a
033     * keep-alive request message.
034     * 
035     * @param session The current session
036     * @param message teh message to check
037     */
038    boolean isRequest(IoSession session, Object message);
039
040    /**
041     * @return <tt>true</tt> if and only if the specified message is a 
042     * keep-alive response message;
043     * 
044     * @param session The current session
045     * @param message teh message to check
046     */
047    boolean isResponse(IoSession session, Object message);
048
049    /**
050     * @return a (new) keep-alive request message or <tt>null</tt> if no request is required.
051     * 
052     * @param session The current session
053     */
054    Object getRequest(IoSession session);
055
056    /**
057     * @return a (new) response message for the specified keep-alive request, or <tt>null</tt> if no response is required.
058     * 
059     * @param session The current session
060     * @param request The request we are lookig for
061     */
062    Object getResponse(IoSession session, Object request);
063}