Getting started with Spring XD(exstream Data)in windows environment and Retrieve twitter live tweets data using Spring XD

Step 0: Java 1.7 or above needs to be installed.
Step1 : Download spring xd from below URL Spring XD
Step2: Unzip and place it where ever you desire. I have placed it in F:\softwares\spring-xd
Step3: Open command Prompt- go to F:\softwares\spring-xd\spring-xd-1.2.0.RELEASE\xd\bin
Step 4: F:\softwares\spring-xd\spring-xd-1.2.0.RELEASE\xd\bin>xd-singlenode
Spring xd will start and displayed as mentioned below.



Step 5: Now open another command prompt to run the shell- F:\softwares\spring-xd\spring-xd-1.2.0.RELEASE\shell\bin
Step 6: F:\softwares\spring-xd\spring-xd-1.2.0.RELEASE\shell\bin>xd-shell
Shell prompt will display as mentioned below.



Step 7: Now we need to create twitter steam inside Spring XD shell
Step 8: We need to create an application inside twitter to get the consumer key and consumer secret key
Step 9: I have created application with name- twitterspringxdsearchjava.
Step 10: Please login into - https://apps.twitter.com and create your own application



Step 11: Now we need to run the created twitter application using spring xd shell

Xd> stream create --name twitterspringxdsearchjava --definition "twittersearch --consumerKey=a7gswQzBwemVLW4rFBz3kERXd --consumerSecret=YewRBaxRZUXP85xsOUnquFCTOcESTy5QCTmfQSUfsuk7S1bCVv --query='java' | file" –deploy

Step 12: output file created inside - F:\tmp\xd\output with name – twitterspringxdsearchjava.out
Step 13: This file will have live tweets data in json format.


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How to load Environment specific properties using Spring PropertyPlaceholderConfigurer

This post will explain how to load environment specific[DEV,SIT,UAT,PROD] properties from the single properties file

Step 1: Create simple java project using eclipse
Step 2: Create a abstract class , with under package - com.javaguru.property, i have created with name - PropertyClient.java

package com.javaguru.property;

public abstract class PropertyClient {

 
 protected String hostName;
 protected String userId;
 protected String password;
 
 
 
 public PropertyClient(String hostName, String userId, String password) {
  super();
  this.hostName = hostName;
  this.userId = userId;
  this.password = password;
  
 }
 
 public PropertyClient(){
  
 }
 
 public String getHostName() {
  return hostName;
 }
 public void setHostName(String hostName) {
  this.hostName = hostName;
 }
 public String getUserId() {
  return userId;
 }
 public void setUserId(String userId) {
  this.userId = userId;
 }
 public String getPassword() {
  return password;
 }
 public void setPassword(String password) {
  this.password = password;
 }
 
 //common methods related to functionality
}
   

Step 3: Create implementation class.

package com.javaguru.property;

public class PropertyClientImpl extends PropertyClient{

 
 public PropertyClientImpl(String hostName, String userId, String password) {
  super(hostName, userId, password);
 }
 public PropertyClientImpl(){
  super();
 }
 //Implementation of abstract methods
}

Step 4: Create property file name called - application.properties under src folder

[DEV]
ftp.dev.hostname=dev.com
ftp.dev.username=user
ftp.dev.password=pass

[SIT]
ftp.sit.hostname=sit.net
ftp.sit.username=user
ftp.sit.password=pass

[UAT]
ftp.uat.hostname=uat.net
ftp.uat.username=user
ftp.uat.password=pass

[PROD]
ftp.prod.hostname=prod.net
ftp.prod.username=user
ftp.prod.password=pass

Step 5: Create applicationContext.xml under src- folder

 

 
   
  application.properties
  
 


    
    
    

Step 6: Create Test class with name - TestEnvSpecificProperty.java- or call the code which ever place you need to load the properties

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.javaguru.property.PropertyClient;
import com.javaguru.property.PropertyClientImpl;
/**
 * 
 * @author siva
 *
 */
public class TestEnvSpecificProperty {

 public static void main(String[] args) {
  //Set which environment properties we need to load.
  System.setProperty("env","dev");
  //load the applicationContext.xml file
  ApplicationContext context =  new ClassPathXmlApplicationContext("applicationContext.xml");
  PropertyClient propertyClient= (PropertyClientImpl)context.getBean("propertyClient");
  //print property details
   System.out.println("Host Name: ["+propertyClient.getHostName()+"]");
   System.out.println("User ID: ["+propertyClient.getUserId()+"]");
   System.out.println("Password: ["+propertyClient.getPassword()+"]");
  
 }
}

Step 7: Output would be like below, if you mention System property as dev

Host Name: [dev.com]
User ID: [user]
Password: [pass]

Step 8: Required jars

commons-codec-1.3.jar
commons-collections-3.2.jar
commons-logging-1.1.1.jar
commons-net-3.3.jar
spring-asm-3.0.5.RELEASE.jar
spring-beans-3.0.4.RELEASE.jar
spring-context-3.0.5.RELEASE.jar
spring-core-3.0.4.RELEASE.jar
spring-expression-3.2.1.release.jar

How to check given interger value is palindrome or not using java

This post will explain you about, given integer palindrome or not.
ex: 121 or 1441 is palindrome- if we write reverse also it should be same

public class PalindromeTest {
 
 public static  boolean isPalindrome(int number){
  boolean isPolindrome = false;
  int palindrome = number;
  int reverseValue = 0;
  while(palindrome !=0){
   int reminder = palindrome % 10;
   reverseValue = reverseValue * 10 + reminder;
   palindrome = palindrome/10;
  }
   if(number==reverseValue){
    isPolindrome = true;
   }
  return isPolindrome;
  
 }
 public static void main(String[] args) {
  System.out.println("Given number is palindrome["+PalindromeTest.isPalindrome(121)+"]");
 }

}

output:

Given number is palindrome[true]

How to print fibonacci series values using java

This post will explain you about how to write fibonacci program for given 10 integer value using java

public class Fibonacci {
 
 public static void main(String[] args) {
  
  int febonacci[] = new int[10];
  febonacci[0]=0;
  febonacci[1]=1;
  for (int i = 2; i < febonacci.length; i++) {
   febonacci[i] = febonacci[i-1]+febonacci[i-2];
   
  }
  for (int i = 0; i < febonacci.length; i++) {
   System.out.print(febonacci[i]+",");
  }
  
  
 }

output:

0,1,1,2,3,5,8,13,21,34

Java interview questions

1.How ArrayList internally works or What will happen if we initialized arraylist size as 10 and tried to add 11th element to arrayList?

Ans: ArrayList uses object[] internally.
ArrayList default size is - 10
If we initialize default size as 10 for arraylist.
Now we are trying add 11th element to ArrayList.
Then it will doubled the size(now size is 20).
Copy previous elements(old array) to new arraylist(new array)
Add the new element(11th element) in newly created array.
Arraylist internally uses array datastructure.

How to do customized Sorting byHashMap key or by value using Comparator - Java

This post will explain how to sort by key and sort by value using HashMap and Comparator.

Step 1: First create a Employee class which is having all the details related to Employee

/**
 * 
 * @author rajusiva
 *
 */

public class Employee {

	
	Integer empId;
	String name;
	Float salary;
	
	public Employee(Integer id,String name, Float sal){
		this.empId = id;
		this.name = name;
		this.salary = sal;
		
	}
	
	@Override
	public String toString() {
		return "Emp Id: "+this.empId+" Name: "+this.name +" salary: " +this.salary;
	}

	public Integer getEmpId() {
		return empId;
	}
	public void setEmpId(Integer empId) {
		this.empId = empId;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Float getSalary() {
		return salary;
	}
	public void setSalary(Float salary) {
		this.salary = salary;
	}

}

Step 2: Below is the class for sort by key and sort by value using comparator

import java.util.Collections;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;

/** This class is used to custom sort using Comparator interface and overriding compare method.
 * 
 * @author rajusiva
 *
 */
public class CustomHashMapSort {
	
	public static void main(String[] args) {
		Map map = new HashMap();
		map.put("205", new Employee(1, "siva", 75000f));
		map.put("202", new Employee(2, "raju", 85000f));
		map.put("203", new Employee(3, "kumar", 50000f));
		map.put("204", new Employee(4, "arjun", 35000f));
		map.put("200", new Employee(5, "neha", 45000f));
		map.put("198", new Employee(6, "sneha", 25000f));
		
		Map sortedMap = new TreeMap(map);
		for (Iterator iterator = sortedMap.keySet().iterator(); iterator.hasNext();) {
			String key = (String) iterator.next();
			Employee emp = map.get(key);
			System.out.println("Sort By key [" + key  +"]  [" + emp + "]");
			
		}
		System.out.println("=============================================");
		HashMap sortedMapByValue = sortByValue(map);
		for (Iterator iterator = sortedMapByValue.keySet().iterator(); iterator.hasNext();) {
			String key = (String) iterator.next();
			Employee emp = map.get(key);
			System.out.println("Sort By Value by Name  Key-[ "+key  +"]  value [" + emp.getName() +"]");
			
		}
		
		
	}
	/**This method will used to sort custom object value type(either empId,name, salary)
	 * 
	 * @param empLoyeeMap of type Map values
	 * @return sorted hashmap values
	 */
	public static  HashMap sortByValue(Map empLoyeeMap) {
		List> list = new java.util.LinkedList>(empLoyeeMap.entrySet());

		Collections.sort(list, new Comparator>() {
        // sort the value using compare method and comparator
		 @Override
		 public int compare(Map.Entry value1, Map.Entry value2) {
		 return (value1.getValue().getName()).compareTo(value2.getValue().getName());
		 }
		});
		
		 HashMap sortedHashMap = new LinkedHashMap();
	       for (Iterator it = list.iterator(); it.hasNext();) {
	              Map.Entry entry = (Map.Entry) it.next();
	              sortedHashMap.put(entry.getKey(), entry.getValue());
	       } 
	       return sortedHashMap;
		
		
	}
	

}

output:

Sort By key [198]  [Emp Id: 6 Name: sneha salary: 25000.0]
Sort By key [200]  [Emp Id: 5 Name: neha salary: 45000.0]
Sort By key [202]  [Emp Id: 2 Name: raju salary: 85000.0]
Sort By key [203]  [Emp Id: 3 Name: kumar salary: 50000.0]
Sort By key [204]  [Emp Id: 4 Name: arjun salary: 35000.0]
Sort By key [205]  [Emp Id: 1 Name: siva salary: 75000.0]
=============================================
Sort By Value by Name  Key-[ 204]  value [arjun]
Sort By Value by Name  Key-[ 203]  value [kumar]
Sort By Value by Name  Key-[ 200]  value [neha]
Sort By Value by Name  Key-[ 202]  value [raju]
Sort By Value by Name  Key-[ 205]  value [siva]
Sort By Value by Name  Key-[ 198]  value [sneha]

Hope this will help you to understand how we can custom object sort by key and value using comparator.

Validate IP address using Java regex

Step 1. Write a java class with name ValidateIPAddress
Step 2. Write a regex pattern. Learn more about reg expression https://docs.oracle.com/javase/tutorial/essential/regex/

public class ValidateIPAddress {
 
 private static final String PATTERN =
   "^([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\." +
   "([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\." +
   "([01]?\\d\\d?|2[0-4]\\d|25[0-5])\\." +
   "([01]?\\d\\d?|2[0-4]\\d|25[0-5])$";
 public static void main(String []args)
    {
     //Pass input value has hard coded value or as a input parameter
            String IP = "000.12.12.034";
            System.out.println(IP.matches(PATTERN));
        

    }
}

Step 3. Description about regex

1. ^                   #line start
2. (                #  start of group 
3. [01]?\\d\\d?        # It can be one or two digits. If three digits appear, it must start either 0 or 1
4. |             # or
5. 2[0-4]\\d        # start with 2, follow by 0-4 and end with any digit (2[0-4][0-9])
6. |                   # or
7. 25[0-5]             # start with 2, follow by 5 and ends with 0-5 (25[0-5])
8. )             #  end of group #2
9. \.                  #  follow by a dot "."
10. ....               # repeat with 3 times (3x)
11. $             #end of the line
 

Step 4. Input 1. Hello.IP 2. 000.12.12.034
Step 5. Output 1. false 2.true

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