public interface

ShutdownNotifier

//  The contents of this file are subject to the Mozilla Public License
//  Version 1.1 (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.mozilla.org/MPL/
//
//  Software distributed under the License is distributed on an "AS IS"
//  basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
//  the License for the specific language governing rights and
//  limitations under the License.
//
//  The Original Code is RabbitMQ.
//
//  The Initial Developer of the Original Code is VMware, Inc.
//  Copyright (c) 2007-2011 VMware, Inc.  All rights reserved.
//


package com.rabbitmq.client;

/**
 * Interface for components that are shutdown capable and
 * that allow listeners to be added for shutdown signals
 *
 * @see ShutdownListener
 * @see ShutdownSignalException
 */
public interface ShutdownNotifier {
    /**
     * Add shutdown listener.
     * If the component is already closed, handler is fired immediately
     *
     * @param listener {@link ShutdownListener} to the component
     */
    public void addShutdownListener(ShutdownListener listener);

    /**
     * Remove shutdown listener for the component.
     *
     * @param listener {@link ShutdownListener} to be removed
     */
    public void removeShutdownListener(ShutdownListener listener);

    /**
     * Get the shutdown reason object
     * @return ShutdownSignalException if component is closed, null otherwise
     */
    public ShutdownSignalException getCloseReason();

    /**
     * Protected API - notify the listeners attached to the component
     * @see com.rabbitmq.client.ShutdownListener
     */
    public void notifyListeners();

    /**
     * Determine whether the component is currently open.
     * Will return false if we are currently closing.
     * Checking this method should be only for information,
     * because of the race conditions - state can change after the call.
     * Instead just execute and try to catch ShutdownSignalException
     * and IOException
     *
     * @return true when component is open, false otherwise
     */
    boolean isOpen();
}