/*
* Licensed to CRATE Technology GmbH ("Crate") under one or more contributor
* license agreements. See the NOTICE file distributed with this work for
* additional information regarding copyright ownership. Crate 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.
*
* However, if you have executed another commercial license agreement
* with Crate these terms will supersede the license and you may use the
* software solely pursuant to the terms of the relevant commercial agreement.
*/
package io.crate.operation.reference.sys.cluster;
import io.crate.metadata.ReferenceImplementation;
import org.apache.lucene.util.BytesRef;
import org.elasticsearch.cluster.service.ClusterService;
import org.elasticsearch.common.inject.Inject;
public class ClusterMasterNodeExpression implements ReferenceImplementation<BytesRef> {
public static final String NAME = "master_node";
private final ClusterService clusterService;
@Inject
public ClusterMasterNodeExpression(ClusterService clusterService) {
this.clusterService = clusterService;
}
@Override
public BytesRef value() {
String masterNodeId = clusterService.state().nodes().getMasterNodeId();
if (masterNodeId == null) {
return null;
}
return new BytesRef(masterNodeId);
}
}