/**
 * Copyright 2007-2016, Kaazing Corporation. All rights reserved.
 *
 * Licensed 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 org.apache.mina.filter.keepalive;

import org.apache.mina.core.session.IoSession;

/**
 * Provides keep-alive messages to {@link KeepAliveFilter}.
 *  
 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
 */
public interface KeepAliveMessageFactory {
    
    /**
     * Returns <tt>true</tt> if and only if the specified message is a
     * keep-alive request message.
     */
    boolean isRequest(IoSession session, Object message);

    /**
     * Returns <tt>true</tt> if and only if the specified message is a 
     * keep-alive response message;
     */
    boolean isResponse(IoSession session, Object message);
    
    /**
     * Returns a (new) keep-alive request message.
     * Returns <tt>null</tt> if no request is required.
     */
    Object getRequest(IoSession session);
    
    /**
     * Returns a (new) response message for the specified keep-alive request.
     * Returns <tt>null</tt> if no response is required.
     */
    Object getResponse(IoSession session, Object request);
}
