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Elasticsearch subproject :server
/*
* 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.discovery;
import org.elasticsearch.ElasticsearchException;
import org.elasticsearch.cluster.ClusterChangedEvent;
import org.elasticsearch.cluster.node.DiscoveryNode;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.component.LifecycleComponent;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.unit.TimeValue;
import java.io.IOException;
/**
* A pluggable module allowing to implement discovery of other nodes, publishing of the cluster
* state to all nodes, electing a master of the cluster that raises cluster state change
* events.
*/
public interface Discovery extends LifecycleComponent {
/**
* Publish all the changes to the cluster from the master (can be called just by the master). The publish
* process should apply this state to the master as well!
*
* The {@link AckListener} allows to keep track of the ack received from nodes, and verify whether
* they updated their own cluster state or not.
*
* The method is guaranteed to throw a {@link FailedToCommitClusterStateException} if the change is not
* committed and should be rejected.
* Any other exception signals the something wrong happened but the change is committed.
*/
void publish(ClusterChangedEvent clusterChangedEvent, AckListener ackListener);
interface AckListener {
/**
* Should be called when the discovery layer has committed the clusters state (i.e. even if this publication fails,
* it is guaranteed to appear in future publications).
* @param commitTime the time it took to commit the cluster state
*/
void onCommit(TimeValue commitTime);
/**
* Should be called whenever the discovery layer receives confirmation from a node that it has successfully applied
* the cluster state. In case of failures, an exception should be provided as parameter.
* @param node the node
* @param e the optional exception
*/
void onNodeAck(DiscoveryNode node, @Nullable Exception e);
}
class FailedToCommitClusterStateException extends ElasticsearchException {
public FailedToCommitClusterStateException(StreamInput in) throws IOException {
super(in);
}
public FailedToCommitClusterStateException(String msg, Object... args) {
super(msg, args);
}
public FailedToCommitClusterStateException(String msg, Throwable cause, Object... args) {
super(msg, cause, args);
}
}
/**
* @return stats about the discovery
*/
DiscoveryStats stats();
/**
* Triggers the first join cycle
*/
void startInitialJoin();
}