/*
* 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 org.elasticsearch.common.Nullable;
import org.elasticsearch.common.Priority;
import org.elasticsearch.common.unit.TimeValue;
import java.util.List;
/**
* Used to apply state updates on nodes that are not necessarily master
*/
public abstract class LocalClusterUpdateTask implements ClusterStateTaskConfig, ClusterStateTaskExecutor<LocalClusterUpdateTask>,
ClusterStateTaskListener {
private final Priority priority;
public LocalClusterUpdateTask() {
this(Priority.NORMAL);
}
public LocalClusterUpdateTask(Priority priority) {
this.priority = priority;
}
public abstract ClusterTasksResult<LocalClusterUpdateTask> execute(ClusterState currentState) throws Exception;
@Override
public final ClusterTasksResult<LocalClusterUpdateTask> execute(ClusterState currentState,
List<LocalClusterUpdateTask> tasks) throws Exception {
assert tasks.size() == 1 && tasks.get(0) == this : "expected one-element task list containing current object but was " + tasks;
ClusterTasksResult<LocalClusterUpdateTask> result = execute(currentState);
return ClusterTasksResult.<LocalClusterUpdateTask>builder().successes(tasks).build(result, currentState);
}
/**
* no changes were made to the cluster state. Useful to execute a runnable on the cluster state applier thread
*/
public static ClusterTasksResult<LocalClusterUpdateTask> unchanged() {
return new ClusterTasksResult<>(null, null);
}
@Override
public String describeTasks(List<LocalClusterUpdateTask> tasks) {
return ""; // one of task, source is enough
}
@Nullable
public TimeValue timeout() {
return null;
}
@Override
public Priority priority() {
return priority;
}
@Override
public final boolean runOnlyOnMaster() {
return false;
}
}