Starting with ElasticSearch

ElasticSearch is a distributed, RESTful search server based on Apache Lucene. The important features of it are listed below:

• Real time data
• RESTful API
• Distributed
• Multi-tenancy
• Document oriented
• Schema free
• Per-operation persistence
• Built on top of Apache Lucene
• High availability
• Full text search
• Conflict management

More detailed information about ElasticSearch can be found at ElasticSearch.org A small example program to add, retrieve and search for documents in ES is given below:

package com.rishav.es;

import static org.elasticsearch.node.NodeBuilder.*;

import java.io.IOException;

import org.apache.lucene.search.TermQuery;
import org.elasticsearch.node.Node;
import org.elasticsearch.client.Client;
import org.elasticsearch.action.get.GetResponse;
import  org.elasticsearch.action.index.IndexResponse;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.action.search.SearchType;

import static org.elasticsearch.common.xcontent.XContentFactory.*;
import org.elasticsearch.common.xcontent.XContentBuilder;
import org.elasticsearch.common.settings.ImmutableSettings;
import org.elasticsearch.common.settings.Settings;
import org.elasticsearch.common.transport.InetSocketTransportAddress;
import org.elasticsearch.client.transport.TransportClient;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.action.search.SearchType;
import org.elasticsearch.index.query.FilterBuilder;
import org.elasticsearch.index.query.FilterBuilders;
import org.elasticsearch.index.query.QueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.FilterBuilders.*;
import org.elasticsearch.index.query.QueryBuilders.*;

public class esConnect {

 // on startup

 public static void main (String args[]) throws IOException{

  // create a client for ElasticSearch running on localhost listening to port 9300
  Node node = nodeBuilder().node();
  Client client = new TransportClient().addTransportAddress(
      new InetSocketTransportAddress("localhost",9300));
  
  // add some record
  IndexResponse iresponse = client.prepareIndex("testindex", "tweets", "1")
     .setSource(jsonBuilder()
                 .startObject()
                     .field("user", "rishav")
                     .field("postDate", "2013-01-30")
                     .field("message", "trying out Elastic Search")
                 .endObject()
               )
     .execute()
     .actionGet();
  
  
  // retrieve record based on id
  GetResponse gresponse = client.prepareGet("testindex", "tweets", "1")
        .execute().actionGet();
  System.out.println(gresponse.getSourceAsString());
  
  // search for a record based on below filters
  SearchResponse sresponse = client.prepareSearch("testindex").
         setSearchType(SearchType.DFS_QUERY_THEN_FETCH).
         setQuery(QueryBuilders.termQuery("user", "rishav")).  // query
         setFilter(FilterBuilders.termFilter("message", "out")).
         execute().
         actionGet();
  System.out.println(sresponse.getHits());
  
  // shutdown client
  client.close();
 }
}