org.apache.flink.runtime.leaderelection.LeaderContender Maven / Gradle / Ivy
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* 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.flink.runtime.leaderelection;
import java.util.UUID;
/**
* Interface which has to be implemented to take part in the leader election process of the {@link
* LeaderElectionService}.
*/
public interface LeaderContender {
/**
* Callback method which is called by the {@link LeaderElectionService} upon selecting this
* instance as the new leader. The method is called with the new leader session ID.
*
* @param leaderSessionID New leader session ID
*/
void grantLeadership(UUID leaderSessionID);
/**
* Callback method which is called by the {@link LeaderElectionService} upon revoking the
* leadership of a former leader. This might happen in case that multiple contenders have been
* granted leadership.
*/
void revokeLeadership();
/**
* Callback method which is called by {@link LeaderElectionService} in case of an error in the
* service thread.
*
* @param exception Caught exception
*/
void handleError(Exception exception);
/**
* Returns the description of the {@link LeaderContender} for logging purposes.
*
* @return Description of this contender.
*/
default String getDescription() {
return "LeaderContender: " + getClass().getSimpleName();
}
}