Examples with MapToExistingElement com.vaadin.flow.component.Component.MapToExistingElement used on opensource projects

Example 1 with MapToExistingElement

use of com.vaadin.flow.component.Component.MapToExistingElement in project flow by vaadin.

the class ComponentUtil method componentFromElement.

/**
 * Creates a new component instance using the given element, maps the
 * component to the element and optionally maps the element to the component
 * (if <code>mapComponent</code> is <code>true</code>).
 * <p>
 * This is a helper method for Element#as and Component#from.
 *
 * @see Component#from(Element, Class)
 * @see Element#as(Class)
 *
 * @param <T>
 *            the component type
 * @param element
 *            the element
 * @param componentType
 *            the component type
 * @param mapComponent
 *            <code>true</code> to also map the element to the component,
 *            <code>false</code> to only map the component to the element
 * @return a new component instance of the given type
 */
public static <T extends Component> T componentFromElement(Element element, Class<T> componentType, boolean mapComponent) {
    if (element == null) {
        throw new IllegalArgumentException("Element to use cannot be null");
    }
    if (componentType == null) {
        throw new IllegalArgumentException("Component type cannot be null");
    }
    MapToExistingElement wrapData = new MapToExistingElement(element, mapComponent);
    try {
        Component.elementToMapTo.set(wrapData);
        UI ui = UI.getCurrent();
        if (ui == null) {
            throw new IllegalStateException("UI instance is not available. " + "It looks like you are trying to execute UI code outside the UI/Servlet dispatching thread");
        }
        Instantiator instantiator = Instantiator.get(ui);
        return instantiator.createComponent(componentType);
    } finally {
        // This should always be cleared, normally it's cleared in Component
        // but in case of exception it might be not cleared
        Component.elementToMapTo.remove();
    }
}