# Selenium — Page Object Model

## Base Page Class

```java
public abstract class BasePage {
    protected WebDriver driver;
    protected WebDriverWait wait;

    public BasePage(WebDriver driver) {
        this.driver = driver;
        this.wait = new WebDriverWait(driver, Duration.ofSeconds(10));
    }

    protected WebElement waitForVisible(By locator) {
        return wait.until(ExpectedConditions.visibilityOfElementLocated(locator));
    }

    protected WebElement waitForClickable(By locator) {
        return wait.until(ExpectedConditions.elementToBeClickable(locator));
    }

    protected void type(By locator, String text) {
        WebElement el = waitForVisible(locator);
        el.clear();
        el.sendKeys(text);
    }

    protected void click(By locator) {
        waitForClickable(locator).click();
    }

    protected String getText(By locator) {
        return waitForVisible(locator).getText();
    }

    protected boolean isDisplayed(By locator) {
        try {
            return waitForVisible(locator).isDisplayed();
        } catch (Exception e) {
            return false;
        }
    }
}
```

## Concrete Page Object

```java
public class LoginPage extends BasePage {
    private By usernameField = By.id("username");
    private By passwordField = By.id("password");
    private By loginButton = By.cssSelector("button[type='submit']");
    private By errorMessage = By.cssSelector(".error-message");

    public LoginPage(WebDriver driver) {
        super(driver);
    }

    public LoginPage navigate() {
        driver.get("https://example.com/login");
        waitForVisible(usernameField);
        return this;
    }

    public DashboardPage loginAs(String username, String password) {
        type(usernameField, username);
        type(passwordField, password);
        click(loginButton);
        return new DashboardPage(driver);
    }

    public String getErrorMessage() {
        return getText(errorMessage);
    }
}
```

## Page Factory Pattern

```java
import org.openqa.selenium.support.FindBy;
import org.openqa.selenium.support.PageFactory;

public class LoginPage {
    @FindBy(id = "username") private WebElement usernameField;
    @FindBy(id = "password") private WebElement passwordField;
    @FindBy(css = "button[type='submit']") private WebElement loginButton;

    public LoginPage(WebDriver driver) {
        PageFactory.initElements(driver, this);
    }

    public void login(String user, String pass) {
        usernameField.sendKeys(user);
        passwordField.sendKeys(pass);
        loginButton.click();
    }
}
```