HasStyleElement

Mixin interface for components exposing styling via CSS classes

Overview

HasStyleElement is a mixin interface for Vaadin components that expose styling through CSS classes. This interface provides methods to retrieve and assert CSS class attributes.

Methods

getCssClass

default String getCssClass()

Gets the raw class attribute value from the component.

Returns: The value of the class attribute as a string, or null if not present

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assertCssClass

default void assertCssClass(String... classnames)

Asserts that the component has exactly the provided class names. When null is passed, asserts that no classes are present.

classnames · String...

The expected class names, or null to assert no classes are present

Implementation Details

This interface extends HasLocatorElement and provides default implementations for all methods.

The assertCssClass() method behavior:

• When class names are provided: asserts the component has exactly those classes
• When null is passed: asserts the component has no classes by checking that the class attribute doesn’t match any pattern

Implementing Classes

This interface is implemented by many Vaadin component wrappers, including:

Layout Components

• AccordionElement
• CardElement
• DetailsElement
• SplitLayoutElement

Navigation & Menu Components

• MenuBarElement
• MenuElement
• MenuItemElement
• ContextMenuElement

Data Display Components

• GridElement
• ListBoxElement
• MessageListElement
• VirtualListElement

Feedback Components

• DialogElement
• NotificationElement
• PopoverElement
• ProgressBarElement

Input Components

• MessageInputElement
• All components implementing HasInputFieldElement (via inheritance)

Other Components

• AvatarElement

Usage Example

import org.vaadin.addons.dramafinder.element.ButtonElement;

// Get a button by text
ButtonElement saveButton = ButtonElement.getByText(page, "Save");

// Get the CSS class attribute
String classes = saveButton.getCssClass();
System.out.println("Classes: " + classes);

// Assert specific classes are present
saveButton.assertCssClass("primary", "large");

// Assert no classes are present
ButtonElement plainButton = ButtonElement.getByText(page, "Cancel");
plainButton.assertCssClass(null);

Usage with Custom Styling

// In your Vaadin application
Button button = new Button("Styled Button");
button.addClassName("custom-style");
button.addClassName("highlighted");

// In your test
ButtonElement button = ButtonElement.getByText(page, "Styled Button");
button.assertCssClass("custom-style", "highlighted");

See Also

• HasInputFieldElement - Includes HasStyleElement for input components
• HasThemeElement - For theme variant styling