/*************************************************************************
 *                                                                       *
 *  SignServer: The OpenSource Automated Signing Server                  *
 *                                                                       *
 *  This software is free software; you can redistribute it and/or       *
 *  modify it under the terms of the GNU Lesser General Public           *
 *  License as published by the Free Software Foundation; either         *
 *  version 2.1 of the License, or any later version.                    *
 *                                                                       *
 *  See terms of license at gnu.org.                                     *
 *                                                                       *
 *************************************************************************/
package org.signserver.server.timedservices;

import org.signserver.server.IWorker;
import org.signserver.server.ServiceExecutionFailedException;

/**
 * ITimedService is an interface that all services should implement.
 * 
 * There exists a BaseTimedService that can be extended covering some of it's functions
 *
 * @author Philip Vendil
 * @version $Id: ITimedService.java 2345 2012-05-06 09:03:57Z netmackan $
 */
public interface ITimedService extends IWorker {

    /**
     * Constant indicating if the service should stop executing
     */
    long DONT_EXECUTE = -1;

    /**
     * Method that should do the actual work and should
     * be implemented by all services. The method is run
     * at a periodical interval defined in getNextInterval.
     * 
     * @throws ServiceExecutionFailedException if execution of a service failed
     */
    void work() throws ServiceExecutionFailedException;

    /**
     * @return should return the milliseconds to next time the service should
     * execute, or -1 (DONE_EXECUTE) if the service should stop executing.
     * 
     * IMPORTANT, this have changed since 2.0 version were seconds were 
     * specified. This shouldn't be confused with the INTERVAL setting 
     * that is still configured in seconds.
     */
    long getNextInterval();

    /**
     * @return true if the service should be active and run
     */
    boolean isActive();

    /**
     * @return true if it should be a singleton only run at one node at
     * the time, of false if it should be run on all nodes simultaneously.
     */
    boolean isSingleton();
}