//
//  ========================================================================
//  Copyright (c) 1995-2014 Mort Bay Consulting Pty. Ltd.
//  ------------------------------------------------------------------------
//  All rights reserved. This program and the accompanying materials
//  are made available under the terms of the Eclipse Public License v1.0
//  and Apache License v2.0 which accompanies this distribution.
//
//      The Eclipse Public License is available at
//      http://www.eclipse.org/legal/epl-v10.html
//
//      The Apache License v2.0 is available at
//      http://www.opensource.org/licenses/apache2.0.php
//
//  You may elect to redistribute this code under either of these licenses.
//  ========================================================================
//

package org.eclipse.jetty.util.component;

import java.util.EventListener;

/* ------------------------------------------------------------ */
/**
 * The lifecycle interface for generic components.
 * <br />
 * Classes implementing this interface have a defined life cycle
 * defined by the methods of this interface.
 *
 * 
 */
public interface LifeCycle
{
	/* ------------------------------------------------------------ */
	/**
	 * Starts the component.
	 * @throws Exception If the component fails to start
	 * @see #isStarted()
	 * @see #stop()
	 * @see #isFailed()
	 */
	public void start()
		throws Exception;

	/* ------------------------------------------------------------ */
	/**
	 * Stops the component.
	 * The component may wait for current activities to complete
	 * normally, but it can be interrupted.
	 * @exception Exception If the component fails to stop
	 * @see #isStopped()
	 * @see #start()
	 * @see #isFailed()
	 */
	public void stop()
		throws Exception;

	/* ------------------------------------------------------------ */
	/**
	 * @return true if the component is starting or has been started.
	 */
	public boolean isRunning();

	/* ------------------------------------------------------------ */
	/**
	 * @return true if the component has been started.
	 * @see #start()
	 * @see #isStarting()
	 */
	public boolean isStarted();

	/* ------------------------------------------------------------ */
	/**
	 * @return true if the component is starting.
	 * @see #isStarted()
	 */
	public boolean isStarting();

	/* ------------------------------------------------------------ */
	/**
	 * @return true if the component is stopping.
	 * @see #isStopped()
	 */
	public boolean isStopping();

	/* ------------------------------------------------------------ */
	/**
	 * @return true if the component has been stopped.
	 * @see #stop()
	 * @see #isStopping()
	 */
	public boolean isStopped();

	/* ------------------------------------------------------------ */
	/**
	 * @return true if the component has failed to start or has failed to stop.
	 */
	public boolean isFailed();

}