Custom ExpectedCondition in Selenium Java

Introduction

Sometimes, built-in wait conditions are not enough. Custom ExpectedCondition lets you wait for exactly what you need in your test.

When you want to wait for a specific text to appear on a page.

When you need to wait for a complex element state that Selenium does not provide by default.

When you want to wait for multiple conditions combined in a special way.

When you want to create reusable wait logic for your tests.

When you want to improve test reliability by waiting smartly for page changes.

Syntax

Selenium Java

ExpectedCondition<T> condition = new ExpectedCondition<T>() {
    public T apply(WebDriver driver) {
        // your custom logic here
        return result != null ? result : null;
    }
};

The apply method returns a value when the condition is met, or null if not yet met.

You can use lambda expressions in Java 8+ for shorter syntax.

Examples

Waits until the element with id 'message' contains the text 'Success'.

Selenium Java

ExpectedCondition<Boolean> textToBePresent = new ExpectedCondition<Boolean>() {
    public Boolean apply(WebDriver driver) {
        return driver.findElement(By.id("message")).getText().contains("Success");
    }
};

Waits until the element with id 'myElement' has the class 'active'. Returns the element if true, else null.

Selenium Java

ExpectedCondition<WebElement> elementHasClass = driver -> {
    WebElement el = driver.findElement(By.id("myElement"));
    String classes = el.getAttribute("class");
    return classes != null && classes.contains("active") ? el : null;
};

Sample Program

This test opens example.com and waits up to 10 seconds for the page title to contain 'Example Domain' using a custom ExpectedCondition. It prints true if the condition is met.

Selenium Java

import org.openqa.selenium.By;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.WebElement;
import org.openqa.selenium.chrome.ChromeDriver;
import org.openqa.selenium.support.ui.ExpectedCondition;
import org.openqa.selenium.support.ui.WebDriverWait;

public class CustomExpectedConditionExample {
    public static void main(String[] args) {
        System.setProperty("webdriver.chrome.driver", "/path/to/chromedriver");
        WebDriver driver = new ChromeDriver();
        try {
            driver.get("https://example.com");

            ExpectedCondition<Boolean> waitForTitleContainsExample = new ExpectedCondition<Boolean>() {
                public Boolean apply(WebDriver d) {
                    return d.getTitle().contains("Example Domain");
                }
            };

            WebDriverWait wait = new WebDriverWait(driver, 10);
            boolean titleIsCorrect = wait.until(waitForTitleContainsExample);

            System.out.println("Title contains 'Example Domain': " + titleIsCorrect);
        } finally {
            driver.quit();
        }
    }
}

Important Notes

Always return null from apply() if the condition is not met yet.

Use WebDriverWait with your custom ExpectedCondition to wait smartly.

Custom ExpectedConditions improve test stability by waiting for exactly what you need.

Summary

Custom ExpectedCondition lets you create your own wait logic.

Use apply() method to check condition and return result or null.

Combine with WebDriverWait to pause test until condition is true.

Practice

1. What is the main purpose of creating a Custom ExpectedCondition in Selenium Java?

easy

A. To automatically generate test reports

B. To replace the WebDriverWait class entirely

C. To speed up test execution by skipping waits

D. To define a specific condition that WebDriverWait will wait for before proceeding

Solution

1. Step 1: Understand the role of ExpectedCondition

   ExpectedCondition defines a condition that WebDriverWait checks repeatedly until it returns a non-null value or true.

2. Step 2: Purpose of Custom ExpectedCondition

   Creating a custom one allows you to specify your own logic for waiting, beyond built-in conditions.

3. Final Answer:

   To define a specific condition that WebDriverWait will wait for before proceeding -> Option D

4. Quick Check:

   Custom ExpectedCondition = Custom wait logic [OK]

Hint: Custom ExpectedCondition defines what to wait for [OK]

Common Mistakes:

• Thinking it replaces WebDriverWait
• Assuming it speeds up tests by skipping waits
• Confusing it with reporting features

2. Which method must be implemented when creating a custom ExpectedCondition in Selenium Java?

easy

A. apply(WebDriver driver)

B. waitForCondition()

C. checkCondition(WebElement element)

D. execute()

Solution

1. Step 1: Recall ExpectedCondition interface

   The ExpectedCondition interface requires implementing the apply method that takes a WebDriver and returns a result or null.

2. Step 2: Identify correct method name

   Only apply(WebDriver driver) is the correct method signature for custom conditions.

3. Final Answer:

   apply(WebDriver driver) -> Option A

4. Quick Check:

   Custom ExpectedCondition method = apply() [OK]

Hint: Custom ExpectedCondition always implements apply(driver) [OK]

Common Mistakes:

• Using wrong method names like waitForCondition or execute
• Confusing with WebElement methods
• Missing the WebDriver parameter

3. Given the following custom ExpectedCondition code snippet, what will be the output if the element with id 'status' has text 'Ready'?

ExpectedCondition<Boolean> condition = driver -> {
  WebElement el = driver.findElement(By.id("status"));
  return el.getText().equals("Ready") ? true : null;
};
WebDriverWait wait = new WebDriverWait(driver, Duration.ofSeconds(5));
boolean result = wait.until(condition);

medium

A. The code will cause a compilation error

B. The wait will pass and result will be true

C. The wait will pass and result will be null

D. The wait will timeout and throw TimeoutException

Solution

1. Step 1: Analyze the condition logic

   The condition returns true if the element's text equals "Ready", otherwise null.

2. Step 2: Understand WebDriverWait behavior

   WebDriverWait waits until the condition returns a non-null, true value. Since text is "Ready", condition returns true immediately.

3. Final Answer:

   The wait will pass and result will be true -> Option B

4. Quick Check:

   Condition true means wait passes [OK]

Hint: If condition returns true, wait.until returns true [OK]

Common Mistakes:

• Thinking null return means pass
• Assuming wait throws error on true
• Confusing null with false

4. Identify the error in this custom ExpectedCondition implementation:

ExpectedCondition<Boolean> condition = driver -> {
  WebElement el = driver.findElement(By.id("submit"));
  if(el.isDisplayed()) {
    return true;
  } else {
    return false;
  }
};

medium

A. findElement should be replaced with findElements

B. Using lambda expression is not allowed for ExpectedCondition

C. Returning false instead of null causes wait.until to stop waiting prematurely

D. Missing try-catch block for NoSuchElementException

Solution

1. Step 1: Understand ExpectedCondition return rules

   ExpectedCondition should return null to continue waiting, true to stop waiting successfully.

2. Step 2: Analyze the code's return values

   Returning false causes wait.until to stop waiting and throw TimeoutException immediately, which is not desired.

3. Final Answer:

   Returning false instead of null causes wait.until to stop waiting prematurely -> Option C

4. Quick Check:

   Return null to keep waiting, not false [OK]

Hint: Return null to wait longer, not false [OK]

Common Mistakes:

• Returning false instead of null to continue wait
• Assuming lambda is invalid
• Ignoring exception handling

5. You want to create a custom ExpectedCondition that waits until a list of elements with class 'item' contains at least 3 visible elements. Which implementation correctly achieves this?

hard

A. ExpectedCondition<Boolean> condition = driver -> {
List<WebElement> items = driver.findElements(By.className("item"));
long visibleCount = items.stream().filter(WebElement::isDisplayed).count();
return visibleCount >= 3 ? true : null;
};

B. ExpectedCondition<Boolean> condition = driver -> {
List<WebElement> items = driver.findElements(By.className("item"));
int count = 0;
for(WebElement item : items) {
if(item.isDisplayed()) count++;
}
return count > 3 ? true : false;
};

C. ExpectedCondition<Boolean> condition = driver -> {
List<WebElement> items = driver.findElements(By.className("item"));
return items.size() >= 3;
};

D. ExpectedCondition<Boolean> condition = driver -> {
List<WebElement> items = driver.findElements(By.className("item"));
return items.stream().allMatch(WebElement::isDisplayed);
};

Solution

1. Step 1: Understand the requirement

   Wait until at least 3 elements with class 'item' are visible (isDisplayed() true).

2. Step 2: Analyze each option

   ExpectedCondition<Boolean> condition = driver -> { List<WebElement> items = driver.findElements(By.className("item")); long visibleCount = items.stream().filter(WebElement::isDisplayed).count(); return visibleCount >= 3 ? true : null; }; counts visible elements and returns true if count >= 3, else null to keep waiting. This matches requirement and wait logic.
   ExpectedCondition<Boolean> condition = driver -> { List<WebElement> items = driver.findElements(By.className("item")); int count = 0; for(WebElement item : items) { if(item.isDisplayed()) count++; } return count > 3 ? true : false; }; returns false if count is not > 3, which stops wait prematurely.
   ExpectedCondition<Boolean> condition = driver -> { List<WebElement> items = driver.findElements(By.className("item")); return items.size() >= 3; }; checks total size, ignoring visibility.
   ExpectedCondition<Boolean> condition = driver -> { List<WebElement> items = driver.findElements(By.className("item")); return items.stream().allMatch(WebElement::isDisplayed); }; waits until all are visible, not at least 3.

3. Final Answer:

   Option A correctly waits for at least 3 visible elements -> Option A

4. Quick Check:

   Return true if condition met, else null to wait [OK]

Hint: Return true if condition met, else null to wait [OK]

Common Mistakes:

• Returning false instead of null to continue wait
• Ignoring visibility check
• Checking all elements visible instead of at least 3