What is Singleton Class Java & How to implement With Selenium WebDriver?

Singleton Class Java: For any java class if we are allowed to create only one object such type of class is called a singleton class. So in this post, we will try to discuss more singleton design patterns or Singleton class and we will also try to implement in selenium with real-time example.

Advantages: if several peoples have the same requirement then it is not recorded to create a separate object for every requirement.

Read Also: Selenium Tutorial

we have to create only one object and we can reuse the same object for every similar requirement is that the performance and the memory utilization will be improved.

How to create our own Singleton Class?

we can create our own singleton classes for this we have to use the private constructor, private static variable and public factory method.

Design Pattern 1

This Pattern, you can see that we are creating an instance much before its requirement. most of the cases it is done in the system startup that’s why it is called as eager initialization singleton pattern.

SingletonDesignDemo1.Java

package com.softwaretestingblog.singleton;
public class SingletonDesignDemo1 
{
   private static SingletonDesignDemo1 obj=new SingletonDesignDemo1();
   
   //We Make Constructor as Private so other class will not create object
   private SingletonDesignDemo1()
   {
      
   }

   public static SingletonDesignDemo1 getObject()
   {
      return obj;
   }
   
   //Other Method protected by Singleton-ness
   public static void demomethod()
   {
      System.out.println("Singleton Design Pattern Method 1");
   }

}

SingletonDesignMain1.Java

package com.softwaretestingblog.singleton;
public class SingletonDesignMain1
{
   public static void main(String[] args) 
   {
      // TODO Auto-generated method stub
      SingletonDesignDemo1 obj= SingletonDesignDemo1.getObject();
      obj.demomethod();
   }
}

We can create a singleton class by using the above method but there is a drawback of this method. in the above method, we create the object irrespective of it’s required or not.  if the instance is not a big object and you can live with it being unused, then it is the best approach.

You Can see the Full image using this link

Note: Runtime class is internally implemented by using this approach.

Design Pattern  2:

In this design pattern, you can say that we are not creating the instance before its requirement.  as you see in the below example in the main class then we call the below statement

SingletonDesignDemo2 obj = SingletonDesignDemo2.getObject();

It will instance and verify if the instance is null or not. if that instance is already initialized then it will allow you to initialize again in this way we are implementing the singleton design pattern here. if the instance is not initialized then it will proceed further and initialize the instance.

SingletonDesignDemo2.java

package com.softwaretestingblog.singleton;
public class SingletonDesignDemo2 
{
   private static SingletonDesignDemo2 obj=null;	
   //We Make Constructor as Private so other class will not create object
   private SingletonDesignDemo2()
   {
      
   }	
   public static SingletonDesignDemo2 getObject()
   {
      if(obj==null)
      {
         obj= new SingletonDesignDemo2();
      }		
      return obj;
   }	
   public static void demoMethod()
   {
      System.out.println("Singleton Design Pattern Method 2");
   }
}

SingletonDesignMain2.Java

package com.softwaretestingblog.singleton;
public class SingletonDesignMain2 
{
   public static void main(String[] args) 
   {
      // TODO Auto-generated method stub
      SingletonDesignDemo2 obj = SingletonDesignDemo2.getObject();
      obj.demoMethod();
   }
}

At any point in time for the test class, we can create only one object. Hence Test class is Singleton class. See the full image use this link

How to Implement Singleton Class with Selenium WebDriver?

ConstantVariable.java

package com.softwaretestingblog.singleton;
public class ConstantVariable 
{
   public static String browserName="Chrome";
   public static String URl="https://www.google.com";
}

BaseClass.java

package com.softwaretestingblog.singleton;
import java.util.concurrent.TimeUnit;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
public class Baseclass 
{
   public static WebDriver driver=null;

   public static void initilize()
   {
      //Use Of Singleton Concept and Initilize webDriver
      if(driver == null)
      {
         if(ConstantVariable.browserName.equalsIgnoreCase("chrome"))
         {
            System.setProperty("webdriver.chrome.driver", "F:\\Photon_Workspace\\SingletonPracticeProject\\Drivers\\chromedriver.exe");
            driver=new ChromeDriver();
         }
         else if(ConstantVariable.browserName.equalsIgnoreCase("Firefox"))
         {
            System.setProperty("webdriver.gecko.driver", "F:\\Photon_Workspace\\SingletonPracticeProject\\Drivers\\geckodriver.exe");
            driver=new FirefoxDriver();
         }
         else if(ConstantVariable.browserName.equalsIgnoreCase("IE"))
         {
            System.setProperty("webdriver.edge.driver", "F:\\Photon_Workspace\\SingletonPracticeProject\\Drivers\\MicrosoftWebDriver.exe");
            driver=new EdgeDriver();
         }
      }
      
      //Perform Basic Operations
      driver.manage().deleteAllCookies();
      driver.manage().window().maximize();
      driver.manage().timeouts().implicitlyWait(30, TimeUnit.SECONDS);
      driver.manage().timeouts().pageLoadTimeout(30, TimeUnit.SECONDS);
   }
   public static void quit()
   {
      driver.quit();
      driver=null; // we destroy the driver object after quit operation
   }
   public static void close()
   {
      driver.close();
      driver=null;  // we destroy the driver object after quit operation
   }	
   public  static void openurl(String URL)
   {
      driver.get(URL);
   }
}

TestClass.java

package com.softwaretestingblog.singleton;
import org.testng.annotations.AfterClass;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.Test;
public class TestClass 
{
   @BeforeClass
   public void setup()
   {
      Baseclass.initilize();
   }
   @Test
   public void openUrl() throws InterruptedException
   {
      Baseclass.openurl(ConstantVariable.URl);
      Thread.sleep(3000);
   }
   @AfterClass
   public void tearDown()
   {
      Baseclass.quit();
   }
}

Check Full Image link

[RemoteTestNG] detected TestNG version 6.14.2
Starting ChromeDriver 2.41.578737 (49da6702b16031c40d63e5618de03a32ff6c197e) on port 49070
Only local connections are allowed.
Sep 21, 2018 10:51:31 AM org.openqa.selenium.remote.ProtocolHandshake createSession
INFO: Detected dialect: OSS
PASSED: openUrl

===============================================
Default test
Tests run: 1, Failures: 0, Skips: 0
===============================================

===============================================
Default suite
Total tests run: 1, Failures: 0, Skips: 0
===============================================

Still, if you have any doubts about the implementation With Selenium Webdriver then drop your query in the comment section.