ElasticSearch Tutorial : Creating index,updating an index,getting value by index search and delete index operation

What is Elastic search??

Why we need it??

Where Elastic search used??

a lot of question..... huh??

so lets start with minimum answer say "short ans". I also assume that you know about elasticsearch but don't know how to code it in java.

ElasticSearch is noting but a full Text search engine with an http web interface. ElasticSearch is developed in java. it also supports distributed operation as well.

we need it because it's search like NRT(Near Real Time). that's means search is significantly faster than database. it's schema free. Data store and pull both in json format. High availability and easy to scale.

Large and big big system like Github, Facebook, StackOverFlow etc. usages ElasticSearch.

Architecture is like it has some cluster. under the cluster it has some nodes, under the nodes it has document (we can say it "Index"). to insert data we need to specify the cluster name as well as node name. then create index, index type, and last of all id. under that id we can store data. feeling dizzy huh?? :D

lets see the picture

Fig 1: Elastic Search Architecture 

well, Elastic search has two clients, 

• Transport Client.
• Node Client.

Difference could be found here.

Now we want to go direct installation and coding part.

First you need to install java. For this example i used java 1.7. to see your java proper installed or version type  java -version from your command window.

now download ElasticSearch from here.

unzipping the package you found a folder "elasticsearch-XXXX" (xxx for version).

create a project in netbeans and include all the jars located "elasticsearch/lib" in the classpath.

now say we have a User object having field "id", "userName", "email". we insert that object in elasticsearch,search,update and delete.

Here I use elasticsearch version 2.1.0

I have the project structure like,

Fig 2: project structure

first connect to elasticsearch by your host ip and port by the following code

   public void connect(String host, int port) {  
     try {  
       final Settings settings = Settings.settingsBuilder()  
           .put("path.home", "F:\\elasticsearch-2.1.0")  
           .put("node.name", "node-1")  
           .put("cluster.name", "elasticsearch")  
           .build();  
       if (client == null) {  
         client = TransportClient.builder().settings(settings).build().addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName(host), port));  
       }  
     } catch (Exception e) {  
       e.printStackTrace();  
       try {  
         throw new ConnectException("Can not connect to " + host + ":" + port);  
       } catch (ConnectException ex) {  
         Logger.getLogger(ServiceManagerImpl.class.getName()).log(Level.SEVERE, null, ex);  
       }  
     }  
   }  

here "client" is a object of TransportClient. when we want to connect from program to elasticsearch, then we should use port 9300, and when access from browser then we should use 9200. as data get and store as json format, so before creating an index we need to convert our object as a json format. Here i used jackson object mapper. Object to json conversion code given below,

 private String getJSON(Object o) {  
     ObjectMapper mapper = new ObjectMapper();  
     mapper.setVisibility(JsonMethod.FIELD, JsonAutoDetect.Visibility.ANY);  
     try {  
       return mapper.writeValueAsString(o);  
     } catch (IOException ex) {  
       Logger.getLogger(ServiceManagerImpl.class.getName()).log(Level.SEVERE, null, ex);  
       return null;  
     }  
   }  

all the method in service implementation class given below,

 /*  
  * To change this template, choose Tools | Templates  
  * and open the template in the editor.  
  */  
 package com.elasticsearch.dao.impl;  
 import com.elasticsearch.beans.User;  
 import com.elasticsearch.dao.ServiceManagerInterface;  
 import java.io.IOException;  
 import java.net.ConnectException;  
 import java.net.InetAddress;  
 import java.util.List;  
 import java.util.concurrent.ExecutionException;  
 import java.util.logging.Level;  
 import java.util.logging.Logger;  
 import org.codehaus.jackson.annotate.JsonAutoDetect;  
 import org.codehaus.jackson.annotate.JsonMethod;  
 import org.codehaus.jackson.map.ObjectMapper;  
 import org.elasticsearch.action.bulk.BulkRequestBuilder;  
 import org.elasticsearch.action.bulk.BulkResponse;  
 import org.elasticsearch.action.get.GetResponse;  
 import org.elasticsearch.action.index.IndexResponse;  
 import org.elasticsearch.action.update.UpdateRequest;  
 import org.elasticsearch.action.update.UpdateResponse;  
 import org.elasticsearch.client.Client;  
 import org.elasticsearch.client.transport.TransportClient;  
 import org.elasticsearch.common.settings.Settings;  
 import org.elasticsearch.common.transport.InetSocketTransportAddress;  
 import org.elasticsearch.node.NodeBuilder.*;  
 /**  
  *  
  * @author Ataur Rahman  
  */  
 public class ServiceManagerImpl implements ServiceManagerInterface {  
   private static final String INDEX = "tigerit";  
   private static final String TYPE = "user";  
   Client client;  
   @Override  
   public BulkResponse addUser(List<User> userList) {  
     String data = "";  
     BulkRequestBuilder bulkRequest = client.prepareBulk();  
     if (userList != null && userList.size() > 0) {  
       for (User user : userList) {  
         data = getJSON(user);  
         bulkRequest.add(client.prepareIndex(INDEX, TYPE, user.getId()).setSource(data));  
       }  
       BulkResponse bulkResponse = bulkRequest.execute().actionGet();  
       if (!bulkResponse.hasFailures()) {  
         return bulkResponse;  
       }  
     }  
     return null;  
   }  
   @Override  
   public GetResponse getUser(String id) {  
     GetResponse response = client.prepareGet(INDEX, TYPE, id).get();  
     if (response != null) {  
       System.out.println("ID " + response.getId());  
       System.out.println("INDEX " + response.getIndex());  
       System.out.println("TYPE " + response.getType());  
       String output = getJSON(response.getSource());  
       System.out.println(output);  
     }  
     return response;  
   }  
   @Override  
   public UpdateResponse updateUser(User user) {  
     UpdateRequest updateRequest = new UpdateRequest();  
     UpdateResponse response = new UpdateResponse();  
     updateRequest.index(INDEX);  
     updateRequest.type(TYPE);  
     updateRequest.id(user.getId());  
     updateRequest.doc(getJSON(user));  
     try {  
       response = client.update(updateRequest).get();  
     } catch (InterruptedException ex) {  
       Logger.getLogger(ServiceManagerImpl.class.getName()).log(Level.SEVERE, null, ex);  
       response = null;  
     } catch (ExecutionException ex) {  
       Logger.getLogger(ServiceManagerImpl.class.getName()).log(Level.SEVERE, null, ex);  
       response = null;  
     }  
     return response;  
   }  
   @Override  
   public void connect(String host, int port) {  
     try {  
       final Settings settings = Settings.settingsBuilder()  
           .put("path.home", "F:\\elasticsearch-2.1.0")  
           .put("node.name", "node-1")  
           .put("cluster.name", "elasticsearch")  
           .build();  
       if (client == null) {  
         client = TransportClient.builder().settings(settings).build().addTransportAddress(new InetSocketTransportAddress(InetAddress.getByName(host), port));  
       }  
     } catch (Exception e) {  
       e.printStackTrace();  
       try {  
         throw new ConnectException("Can not connect to " + host + ":" + port);  
       } catch (ConnectException ex) {  
         Logger.getLogger(ServiceManagerImpl.class.getName()).log(Level.SEVERE, null, ex);  
       }  
     }  
   }  
   private String getJSON(Object o) {  
     ObjectMapper mapper = new ObjectMapper();  
     mapper.setVisibility(JsonMethod.FIELD, JsonAutoDetect.Visibility.ANY);  
     try {  
       return mapper.writeValueAsString(o);  
     } catch (IOException ex) {  
       Logger.getLogger(ServiceManagerImpl.class.getName()).log(Level.SEVERE, null, ex);  
       return null;  
     }  
   }  
   @Override  
   public BulkResponse deleteUser(List<User> userList) {  
     BulkRequestBuilder requestBuilder = client.prepareBulk();  
     if (userList != null && userList.size() > 1) {  
       for (User user : userList) {  
         requestBuilder.add(client.prepareDelete(INDEX, TYPE, user.getId()));  
       }  
     }  
     BulkResponse bulkResponse = requestBuilder.execute().actionGet();  
     if (bulkResponse != null && !bulkResponse.hasFailures()) {  
       System.out.println("Index " + " deleted");  
     }  
     return bulkResponse;  
   }  
 }  

Service interface class given below,

 /*  
  * To change this template, choose Tools | Templates  
  * and open the template in the editor.  
  */  
 package com.elasticsearch.dao;  
 import com.elasticsearch.beans.User;  
 import java.util.List;  
 import org.elasticsearch.action.bulk.BulkResponse;  
 import org.elasticsearch.action.get.GetResponse;  
 import org.elasticsearch.action.update.UpdateResponse;  
 /**  
  *  
  * @author Ataur Rahman  
  */  
 public interface ServiceManagerInterface {  
   BulkResponse addUser(List<User> userList);  
   GetResponse getUser(String id);  
   BulkResponse deleteUser(List<User> userList);  
   UpdateResponse updateUser(User user);  
   void connect(String host, int port);  
 }  

and last of all, the main method,

 /*  
  * To change this template, choose Tools | Templates  
  * and open the template in the editor.  
  */  
 package com.elasticsearch.client;  
 import com.elasticsearch.beans.User;  
 import com.elasticsearch.dao.ServiceManagerInterface;  
 import com.elasticsearch.dao.impl.ServiceManagerImpl;  
 import java.util.ArrayList;  
 import java.util.List;  
 import java.util.regex.Matcher;  
 import java.util.regex.Pattern;  
 import org.elasticsearch.action.bulk.BulkResponse;  
 import org.elasticsearch.action.delete.DeleteResponse;  
 import org.elasticsearch.action.get.GetResponse;  
 import org.elasticsearch.action.index.IndexResponse;  
 import org.elasticsearch.action.update.UpdateResponse;  
 /**  
  *  
  * @author Ataur Rahman  
  */  
 public class ElasticSearchClient {  
   public static void main(String[] args) {  
     ServiceManagerInterface service = new ServiceManagerImpl();  
     service.connect("192.168.103.11", 9300);  
     User user = new User();  
     user.setId("5");  
     List<User> userList = prepareUserForInsertion();  
     BulkResponse response = service.addUser(userList);  
     if(response!= null){  
       if(!response.hasFailures())  
         System.out.println("All data inserted");  
       else System.out.println("Error,All data not inserted");  
     }  
     GetResponse getResponse = service.getUser(user.getId());  
     if(getResponse!= null){  
       System.out.println("Getting the user with id : "+getResponse.getId());  
     }  
     user.setEmail("email@email.com");  
     UpdateResponse updateResponse = service.updateUser(user);  
     if(updateResponse!= null){  
       System.out.println("User updated with id"+updateResponse.getId());  
     }  
     BulkResponse deleteResponse = service.deleteUser(prepareUserForInsertion());  
     if(deleteResponse!= null && !deleteResponse.hasFailures()){  
       System.out.println("All Item deleted ");  
     }  
   }  
   public static List<User> prepareUserForInsertion(){  
     User user;  
     List <User> userList = new ArrayList<User>();  
     for(int i=1; i<=100; i++){  
       user = new User();  
       user.setId(String.valueOf(i));  
       System.out.println(user.getId());  
       user.setUserName("munna"+String.valueOf(i));  
       System.out.println(user.getUserName());  
       user.setEmail("munna@munna.com"+String.valueOf(i));  
       System.out.println(user.getEmail());  
       userList.add(user);  
     }  
     return userList;  
   }  
 }  

before test it comment out your delete block because it deleted all the inserted data. now we are going to test it. From your browser type
http://<your_ip_address>/INDEX/TYPE/ID?pretty=true
you will see the output in json format.
Cheers.... :)