com.vaadin.flow.component

Class Composite<T extends Component>

java.lang.Object

com.vaadin.flow.component.Component

com.vaadin.flow.component.Composite<T>

Type Parameters:

T - the type of the content

All Implemented Interfaces:

AttachNotifier, DetachNotifier, HasElement, Serializable

Direct Known Subclasses:

AbstractCompositeField

public abstract class Composite<T extends Component>
extends Component

A composite encapsulates a Component tree to allow creation of new components by composing existing components. By encapsulating the component, its API can be hidden or presented in a different way for the user of the composite.

The encapsulated component tree is available through getContent(). Composite will by default look at the generic type declaration of its subclass to find the content type and create an instance if the type has a no-args constructor. You can also override initContent() to manually create the component tree. The encapsulated component itself can contain more components.

Composite is a way to hide API on the server side. It does not contribute any element to the Element tree.

Since:

1.0

Author:

Vaadin Ltd

See Also:

Serialized Form

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	Composite() Creates a new composite.

Method Summary

Modifier and Type	Method and Description
Stream<Component>	getChildren() Gets the child components of this composite.
T	getContent() Gets the content of the composite, i.e.
Element	getElement() Gets the root element of this composite.
protected T	initContent() Called when the content of this composite is requested for the first time.

Methods inherited from class com.vaadin.flow.component.Component

addListener, fireEvent, from, get, getEventBus, getId, getLocale, getParent, getTranslation, getTranslation, getUI, hasListener, isTemplateMapped, isVisible, onAttach, onDetach, onEnabledStateChanged, set, setElement, setId, setVisible

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.vaadin.flow.component.AttachNotifier

addAttachListener

Methods inherited from interface com.vaadin.flow.component.DetachNotifier

addDetachListener

Constructor Detail

Composite

protected Composite()

Creates a new composite.

To define your own composite, extend this class and implement initContent().

Method Detail

initContent

protected T initContent()

Called when the content of this composite is requested for the first time.

This method should initialize the component structure for the composite and return the root component.

By default, this method uses reflection to instantiate the component based on the generic type of the sub class.

Returns:

the root component which this composite wraps, never null

getContent

public T getContent()

Gets the content of the composite, i.e. the component the composite is wrapping.

Returns:

the content for the composite, never null

getElement

public Element getElement()

Gets the root element of this composite.

For a composite, the root element is the same as the root element of the content of the composite.

Specified by:

getElement in interface HasElement

Overrides:

getElement in class Component

Returns:

the root element of this component

getChildren

public Stream<Component> getChildren()

Gets the child components of this composite.

A composite always has one child component, returned by initContent().

Overrides:

getChildren in class Component

Returns:

the child component of this composite

See Also:

Id