/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.activemq.apollo.util;


import org.fusesource.hawtdispatch.Task;

/**
 * The core lifecyle interface for ActiveMQ components.
 *
 * @version $Revision: 1.1 $
 */
public interface Service {

    /**
     * Starts the service.  Executes the onComplete runnable once the service has fully started up.
     *
     * @param onComplete my be set to null if not interested in a callback.
     */
    void start(Task onComplete) throws Exception;

    /**
     * Stops the service.  Executes the onComplete runnable once the service has fully stopped.
     *
     * @param onComplete my be set to null if not interested in a callback.
     */
    void stop(Task onComplete) throws Exception;

    /**
     * @return the error that caused the service to not start.
     */
    public Throwable service_failure();

}
