com.vaadin.flow.data.renderer

Class ComponentRenderer<COMPONENT extends Component,SOURCE>

java.lang.Object

com.vaadin.flow.data.renderer.Renderer<SOURCE>

com.vaadin.flow.data.renderer.ComponentRenderer<COMPONENT,SOURCE>

Type Parameters:

COMPONENT - the type of the output component

SOURCE - the type of the input model object

All Implemented Interfaces:

Serializable

Direct Known Subclasses:

BasicRenderer, IconRenderer, TextRenderer

public class ComponentRenderer<COMPONENT extends Component,SOURCE>
extends Renderer<SOURCE>

Base class for all renderers that support arbitrary Components.

Components that support renderers should use the appropriate method from this class to provide component rendering: Renderer.render(Element, DataKeyMapper) for components that uses <template>, and createComponent(Object) for components that use light-dom.

Since:

1.0.

Author:

Vaadin Ltd

See Also:

Serialized Form

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	ComponentRenderer() Default constructor, that can be used by subclasses which supports different ways of creating components, other than those defined in the other constructors.
	ComponentRenderer(SerializableFunction<SOURCE,COMPONENT> componentFunction) Creates a new ComponentRenderer that uses the componentFunction to generate new Component instances.
	ComponentRenderer(SerializableFunction<SOURCE,COMPONENT> componentFunction, SerializableBiFunction<Component,SOURCE,Component> componentUpdateFunction) Creates a new ComponentRenderer that uses the componentFunction to generate new Component instances, and a componentUpdateFunction to update existing Component instances.
	ComponentRenderer(SerializableSupplier<COMPONENT> componentSupplier) Creates a new ComponentRenderer that uses the componentSupplier to generate new Component instances.
	ComponentRenderer(SerializableSupplier<COMPONENT> componentSupplier, SerializableBiConsumer<COMPONENT,SOURCE> itemConsumer) Creates a new ComponentRenderer that uses the componentSupplier to generate new Component instances, and the itemConsumer to set the related items.

Method Summary

Modifier and Type	Method and Description
COMPONENT	createComponent(SOURCE item) Creates a component for a given object model item.
Rendering<SOURCE>	render(Element container, DataKeyMapper<SOURCE> keyMapper, Element contentTemplate) Handles the rendering of the model objects by using the given <template> element in the given container.
void	setComponentRendererTag(String componentRendererTag) Sets the tag of the webcomponent used at the client-side to manage component rendering inside <template>.
Component	updateComponent(Component currentComponent, SOURCE item) Called when the item is updated.

Methods inherited from class com.vaadin.flow.data.renderer.Renderer

getEventHandlers, getValueProviders, render, setEventHandler, setProperty

Methods inherited from class java.lang.Object

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

Constructor Detail

ComponentRenderer

public ComponentRenderer(SerializableSupplier<COMPONENT> componentSupplier,
                         SerializableBiConsumer<COMPONENT,SOURCE> itemConsumer)

Creates a new ComponentRenderer that uses the componentSupplier to generate new Component instances, and the itemConsumer to set the related items.

Some components may support several rendered components at once, so different component instances should be created for each different item for those components.

Parameters:

componentSupplier - a supplier that can generate new component instances

itemConsumer - a setter for the corresponding item for the rendered component

ComponentRenderer

public ComponentRenderer(SerializableSupplier<COMPONENT> componentSupplier)

Creates a new ComponentRenderer that uses the componentSupplier to generate new Component instances.

This constructor is a convenient way of providing components to a template when the actual model item doesn't matter for the component instance.

Some components may support several rendered components at once, so different component instances should be created for each different item for those components.

Parameters:

componentSupplier - a supplier that can generate new component instances

ComponentRenderer

public ComponentRenderer(SerializableFunction<SOURCE,COMPONENT> componentFunction)

Creates a new ComponentRenderer that uses the componentFunction to generate new Component instances. The function takes a model item and outputs a component instance.

Some components may support several rendered components at once, so different component instances should be created for each different item for those components.

Parameters:

componentFunction - a function that can generate new component instances

See Also:

ComponentRenderer(SerializableFunction, SerializableBiFunction)

ComponentRenderer

public ComponentRenderer(SerializableFunction<SOURCE,COMPONENT> componentFunction,
                         SerializableBiFunction<Component,SOURCE,Component> componentUpdateFunction)

Creates a new ComponentRenderer that uses the componentFunction to generate new Component instances, and a componentUpdateFunction to update existing Component instances.

The componentUpdateFunction can return a different component than the one previously created. In those cases, the new instance is used, and the old is discarded.

Some components may support several rendered components at once, so different component instances should be created for each different item for those components.

Parameters:

componentFunction - a function that can generate new component instances

componentUpdateFunction - a function that can update the existing component instance for the item, or generate a new component based on the item update. When the function is null, the componentFunction is always used instead

ComponentRenderer

protected ComponentRenderer()

Default constructor, that can be used by subclasses which supports different ways of creating components, other than those defined in the other constructors.

Method Detail

render

public Rendering<SOURCE> render(Element container,
                                DataKeyMapper<SOURCE> keyMapper,
                                Element contentTemplate)

Description copied from class: Renderer

Handles the rendering of the model objects by using the given <template> element in the given container.

Subclasses of Renderer usually override this method to provide additional features.

Overrides:

render in class Renderer<SOURCE>

Parameters:

container - the element in which the template will be attached to, not null

keyMapper - mapper used internally to fetch items by key and to provide keys for given items. It is required when either event handlers or DataGenerator are supported

contentTemplate - the <template> element to be used for rendering in the container, not null

Returns:

the context of the rendering, that can be used by the components to provide extra customization

setComponentRendererTag

public void setComponentRendererTag(String componentRendererTag)

Sets the tag of the webcomponent used at the client-side to manage component rendering inside <template>. By default it uses <flow-component-renderer>.

Parameters:

componentRendererTag - the tag of the client-side webcomponent for component rendering, not null

createComponent

public COMPONENT createComponent(SOURCE item)

Creates a component for a given object model item. Subclasses can override this method to provide specific behavior.

Parameters:

item - the model item, possibly null

Returns:

a component instance representing the provided item

updateComponent

public Component updateComponent(Component currentComponent,
                                 SOURCE item)

Called when the item is updated. By default, a new Component is created (via createComponent(Object)) when the item is updated, but setting a update function via the ComponentRenderer(SerializableFunction, SerializableBiFunction) can change the behavior.

Parameters:

currentComponent - the current component used to render the item, not null

item - the updated item

Returns:

the component that should be used to render the updated item. The same instance can be returned, or a totally new one, but not null.