/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.cluster;
import java.util.function.Predicate;
public final class MasterNodeChangePredicate {
private MasterNodeChangePredicate() {
}
/**
* builds a predicate that will accept a cluster state only if it was generated after the current has
* (re-)joined the master
*/
public static Predicate<ClusterState> build(ClusterState currentState) {
final long currentVersion = currentState.version();
final String currentMaster = currentState.nodes().getMasterNodeId();
return newState -> {
final String newMaster = newState.nodes().getMasterNodeId();
final boolean accept;
if (newMaster == null) {
accept = false;
} else if (newMaster.equals(currentMaster) == false){
accept = true;
} else {
accept = newState.version() > currentVersion;
}
return accept;
};
}
}