/**
* 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.hadoop.hdfs.server.datanode;
import org.apache.hadoop.util.ServicePlugin;
public abstract class DatanodePlugin implements ServicePlugin {
// ServicePlugin hooks
/** {@inheritDoc} */
public abstract void start(Object obj);
/** {@inheritDoc} */
public abstract void stop();
// Datanode specific hooks
/**
* The DataNode has registered itself with the NameNode during the initial
* startup sequence. This is called before the DataNode Thread has started
* running.
*/
public void initialRegistrationComplete() {}
/**
* The DataNode has re-registered itself with the NameNode in response to a
* DNA_REGISTER event. This occurs when the NN has lost and regained contact
* with the DataNode.
*/
public void reregistrationComplete() {}
}