The following is sample Java program to get the list of aliases in an Elasticsearch instance.

Sample Program:

package com.report.test;

import java.util.ArrayList;
import java.util.List;
import org.elasticsearch.client.Client;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.cluster.metadata.AliasMetaData;
import org.elasticsearch.common.collect.ImmutableOpenMap;
import org.elasticsearch.common.settings.ImmutableSettings;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.InetSocketTransportAddress;

public class SampleProgram{
     public static void main(String[] args) {
          String hostname = "localhost";
          String clusterName = "elasticsearch";

          Settings settings = ImmutableSettings.settingsBuilder().put("client.transport.sniff", true).put("cluster.name", clusterName).build();
          Client esclient = new TransportClient(settings).addTransportAddress(new InetSocketTransportAddress(hostname, 9300));

          List aliasList = new ArrayList();
	  ImmutableOpenMap<String, ImmutableOpenMap<String, AliasMetaData>> object = esclient.admin().cluster().prepareState().execute().actionGet().getState().getMetaData().getAliases();
	  Object[] aliasKeyObjectArray = object.keys().toArray();

	  for (Object aliasObject : aliasKeyObjectArray) {
	       aliasList.add(aliasObject.toString());
          }

          System.out.println("Alias List:");
          for (String alias : aliasList) {
	       System.out.println(alias);
          }
     }
}

Sample Output:

Alias List:
student_group
sample_alias

Related Links: