Hello Folks,
In this post we are going to see something interesting concepts about waits in Selenium WebDriver.
Generally Selenium professionals know that there are three types of waits in Selenium WebDriver:-
- Implicit Wait
- Explicit Wait
- Fluent Wait
In fact there are only two types of waits:-
- Implicit wait
- Explicit wait
We can implement Explicit wait in two ways:-
Selenium official document talks the same. They have not mentioned Fluent wait separately .
Brief about both waits as per Selenium Documentation:-
An implicit wait is to tell WebDriver to poll the DOM for a certain amount of time when trying to find an element or elements if they are not immediately available. The default setting is 0. Once set, the implicit wait is set for the life of the WebDriver object instance.
WebDriver driver = new FirefoxDriver();
driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);
driver.get("some URL");
WebElement myDynamicElement = driver.findElement(By.id("someID"));
An explicit wait is code you define to wait for a certain condition to occur before proceeding further in the code. WebDriverWait in combination with ExpectedCondition (Note- ExpectedCondition is an interface while
ExpectedConditions is a class) is one way to do this. That condition can be implemented either using ExpectedConditions methods or override apply() methods and write your own condition.
Example Code:-
WebDriver driver = new FirefoxDriver();
driver.get("some url");
WebDriverWait wait = new WebDriverWait(driver, 10);
// Using readymade wat conditions
wait.until(ExpectedConditions.presenceOfElementLocated(By.id("someID")));
// Using own way of waiting
boolean foo = wait.until(new Function < WebDriver, Boolean > () {
public boolean apply(WebDriver driver) {
return driver.findElement(By.id("foo")).isDisplayed();
}
});
FluentWait is a class in Selenium WebDriver which implements Wait interface and WebDriverWait is direct known subclass to it. It means all are in same hierarchy. Fluent wait is an implementation of the Wait interface that may have its timeout and polling interval configured on the fly. WebDriverWait is a specialization of FluentWait that uses WebDriver instances. To be more clear, FluentWait is a generic class (public class FluentWait implements Wait) while WebDriverWait is specialization of FluentWait (public class WebDriverWait extends FluentWait). WebDriverWait is designed to work for WebDriver exclusively.
So if we implement Explicit wait using either FluentWait or WebDriverWait, we can configure with desired polling interval and ignore one or more exceptions. Refer below examples:-
Wait wait = new FluentWait(driver).withTimeout(Duration.ofSeconds(30)) .pollingEvery(Duration.ofSeconds(5))
.ignoring(NoSuchElementException.class);
WebElement foo = wait.until(new Function() { public WebElement apply(WebDriver driver) { return driver.findElement(By.id("foo")); }
});
WebDriver driver = new FirefoxDriver();
driver.get("Some URL");
WebElement myDynamicElement = (new WebDriverWait(driver, 10))
.until(ExpectedConditions.presenceOfElementLocated(By.id("someID")));
We can use either readymade methods available in ExpectedConditions class or we can create our own wait conditions by overriding apply() method of Function interface in until() method. Maximum wait conditions methods of ExpectedConditions class overrides apply() method.
FluentWait class has different methods to configure wait instance. For example:- withTimeout(), pollingEvery(), ignoring() etc. This class is generic so all methods as well.
In WebDriverWait class which is specialization of FluentWait with WebDriver and provides a way to configure wait instance easily. For example:-
When we write below line:-
WebDriverWait wait = new WebDriverWait(driver, 30);
It calls constructor of FluentWait and set default polling interval time (DEFAULT_SLEEP_TIMEOUT) which is 500 ms and ignore instances of NotFoundException that are encountered (thrown) by default in the ‘until’ condition. You can change default polling interval and ignoring exceptions as well as shown below:-
WebDriverWait wait1 = new WebDriverWait(driver,30);wait1.pollingEvery(Duration.ofSeconds(2));wait1.ignoring(ElementClickInterceptedException.class);
You can also user overloaded WebDriverWait constructor to set interval time as below:-
WebDriverWait wait1= new WebDriverWait(driver, 30, 5000);
Above statement works in the same way except instead of setting default polling interval time as 500 ms. It will set polling interval time as 5 seconds.
So to summarize, WebDriverWait is a FluentWait (Inheritance) and FluentWait is Explicit wait in Selenium WebDriver.
It is also not correct that in WebDriverWait we can use only ExpectedConditions class wait methods and in FluentWait , we can use only apply() method. We can set custom polling interval and ignore exceptions in both implementation i.e. WebDriverWait & FluentWait.
Explicit Wait as WebDriverWait with ExpectedConditions and apply() method:-
package WaitExamples; import java.time.Duration;
import java.util.Date;
import java.util.function.Function; import org.openqa.selenium.By;
import org.openqa.selenium.ElementNotInteractableException;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.WebDriverWait; import io.github.bonigarcia.wdm.WebDriverManager; public class ExplicitWaitAsWebDriverWaitExample { public static void main(String[] args) throws InterruptedException { WebDriverManager.chromedriver().setup(); WebDriver driver = new ChromeDriver(); driver.manage().window().maximize(); driver.get("http://www.itgeared.com/demo/1502-javascript_countdown.html"); // Configuring a WebDriverWait with polling interval and ignoring exception WebDriverWait wait = new WebDriverWait(driver,30); wait.pollingEvery(Duration.ofMillis(5000)); wait.ignoring(ElementNotInteractableException.class); // Using ready made wait conditions of ExpectedCOnditions class wait.until(ExpectedConditions.elementToBeClickable(driver.findElement(By.id("myBtn")))); System.out.println("Element is ready to be clicked."); // Refreshing the page driver.get("http://www.itgeared.com/demo/1502-javascript_countdown.html"); // Overriding apply() method to created our own wait condition for WebDriverWait boolean isClickable = wait.until(new Function() { public Boolean apply(WebDriver driver) { System.out.println("Interval time : "+new Date()); String text= driver.findElement(By.id("myBtn")).getText(); if(text.equals("Click Me!")) return true; return false; } }); if(isClickable) System.out.println("Element is ready to be clicked."); driver.quit(); }
}
Output:-
Element is ready to be clicked.Interval time : Thu Jun 20 06:51:08 IST 2019Interval time : Thu Jun 20 06:51:13 IST 2019Interval time : Thu Jun 20 06:51:18 IST 2019Interval time : Thu Jun 20 06:51:23 IST 2019
Element is ready to be clicked.
You can see how we set custom polling interval in WebDriverWait.
Explicit Wait as WebDriverWait with ExpectedConditions and apply() method:-
package WaitExamples; import java.time.Duration;
import java.util.Date;
import java.util.NoSuchElementException;
import java.util.function.Function; import org.openqa.selenium.By;
import org.openqa.selenium.ElementNotInteractableException;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.support.ui.ExpectedConditions;
import org.openqa.selenium.support.ui.FluentWait;
import org.openqa.selenium.support.ui.Wait;
import org.openqa.selenium.support.ui.WebDriverWait; import io.github.bonigarcia.wdm.WebDriverManager; public class ExplicitWaitAsFluentWaitExample { public static void main(String[] args) throws InterruptedException { WebDriverManager.chromedriver().setup(); WebDriver driver = new ChromeDriver(); driver.manage().window().maximize(); driver.get("http://www.itgeared.com/demo/1502-javascript_countdown.html"); // Configuring a FluentWait with polling interval and ignoring exception Wait wait = new FluentWait(driver) .withTimeout(Duration.ofMillis(30000)) .pollingEvery(Duration.ofMillis(5000)) .ignoring(NoSuchElementException.class); // Using ready made wait conditions of ExpectedCOnditions class wait.until(ExpectedConditions.elementToBeClickable(driver.findElement(By.id("myBtn")))); System.out.println("Element is ready to be clicked."); // Refreshing the page driver.get("http://www.itgeared.com/demo/1502-javascript_countdown.html"); // Overriding apply() method to created our own wait condition for WebDriverWait boolean isClickable = wait.until(new Function() { public Boolean apply(WebDriver driver) { System.out.println("Interval time : "+new Date()); String text= driver.findElement(By.id("myBtn")).getText(); if(text.equals("Click Me!")) return true; return false; } }); if(isClickable) System.out.println("Element is ready to be clicked."); driver.quit(); }
}
#ThanksForReading