/**
* 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.notifier;
/**
* Must be implemented by the classes which want to receive namespace
* notifications.
*/
public interface Watcher {
/**
* Called when a notification was received.
* @param notification
*/
public void handleNamespaceNotification(NamespaceNotification notification);
/**
* Called when the connection to the server failed and recovering the
* connection trough all the other servers failed.
*/
public void connectionFailed();
/**
* Called when the connection to the server is established. This will be
* called on start-up and after a connectionFailed method call. You can only
* place watches after this method has been called given that connectionFailed
* was not called since then.
*/
public void connectionSuccesful();
}