org.apache.hive.service.Service Maven / Gradle / Ivy
/**
* 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.hive.service;
import org.apache.hadoop.hive.conf.HiveConf;
/**
* Service.
*
*/
public interface Service {
/**
* Service states
*/
public enum STATE {
/** Constructed but not initialized */
NOTINITED,
/** Initialized but not started or stopped */
INITED,
/** started and not stopped */
STARTED,
/** stopped. No further state transitions are permitted */
STOPPED
}
/**
* Initialize the service.
*
* The transition must be from {@link STATE#NOTINITED} to {@link STATE#INITED} unless the
* operation failed and an exception was raised.
*
* @param config
* the configuration of the service
*/
void init(HiveConf conf);
/**
* Start the service.
*
* The transition should be from {@link STATE#INITED} to {@link STATE#STARTED} unless the
* operation failed and an exception was raised.
*/
void start();
/**
* Stop the service.
*
* This operation must be designed to complete regardless of the initial state
* of the service, including the state of all its internal fields.
*/
void stop();
/**
* Register an instance of the service state change events.
*
* @param listener
* a new listener
*/
void register(ServiceStateChangeListener listener);
/**
* Unregister a previously instance of the service state change events.
*
* @param listener
* the listener to unregister.
*/
void unregister(ServiceStateChangeListener listener);
/**
* Get the name of this service.
*
* @return the service name
*/
String getName();
/**
* Get the configuration of this service.
* This is normally not a clone and may be manipulated, though there are no
* guarantees as to what the consequences of such actions may be
*
* @return the current configuration, unless a specific implementation chooses
* otherwise.
*/
HiveConf getHiveConf();
/**
* Get the current service state
*
* @return the state of the service
*/
STATE getServiceState();
/**
* Get the service start time
*
* @return the start time of the service. This will be zero if the service
* has not yet been started.
*/
long getStartTime();
}