org.elasticsearch.cluster.LocalNodeMasterListener Maven / Gradle / Ivy

Show more of this group Show more artifacts with this name
Show all versions of org.apache.servicemix.bundles.elasticsearch

This OSGi bundle wraps ${pkgArtifactId} ${pkgVersion} jar file.

There is a newer version: 7.10.2_1

Show newest version

/*
 * Licensed to Elastic Search and Shay Banon 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;

/**
 * Enables listening to master changes events of the local node (when the local node becomes the master, and when the local
 * node cease being a master).
 */
public interface LocalNodeMasterListener {

    /**
     * Called when local node is elected to be the master
     */
    void onMaster();

    /**
     * Called when the local node used to be the master, a new master was elected and it's no longer the local node.
     */
    void offMaster();

    /**
     * The name of the executor that the implementation of the callbacks of this lister should be executed on. The thread
     * that is responsible for managing instances of this lister is the same thread handling the cluster state events. If
     * the work done is the callbacks above is inexpensive, this value may be {@link org.elasticsearch.threadpool.ThreadPool.Names#SAME SAME}
     * (indicating that the callbaks will run on the same thread as the cluster state events are fired with). On the other hand,
     * if the logic in the callbacks are heavier and take longer to process (or perhaps involve blocking due to IO operations),
     * prefer to execute them on a separte more appropriate executor (eg. {@link org.elasticsearch.threadpool.ThreadPool.Names#GENERIC GENERIC}
     * or {@link org.elasticsearch.threadpool.ThreadPool.Names#MANAGEMENT MANAGEMENT}).
     *
     * @return The name of the executor that will run the callbacks of this listener.
     */
    String executorName();

}