Package 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.LitRenderer<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, HierarchyColumnComponentRenderer, IconRenderer
@JsModule("./flow-component-renderer.js") public class ComponentRenderer<COMPONENT extends Component,SOURCE> extends LitRenderer<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.

Author:
Vaadin Ltd
See Also:

  • Constructor Details

    • 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

      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

  • Method Details

    • getTemplateExpression

      protected String getTemplateExpression()
      Description copied from class: LitRenderer
      Returns the Lit template expression used to render items.
      Overrides:
      getTemplateExpression in class LitRenderer<SOURCE>
      Returns:
      the template expression

    • render

      public Rendering<SOURCE> render(Element owner, DataKeyMapper<SOURCE> keyMapper, String rendererName)
      Description copied from class: Renderer
      Registers a renderer function with the given name to the given container element. Creates the setup to handle rendering of individual data items as requested by the renderer function invocation.
      Overrides:
      render in class LitRenderer<SOURCE>
      Parameters:
      owner - the element which accepts the renderer function on the client.
      keyMapper - mapper used internally to fetch items by key and to provide keys for given items.
      rendererName - name of the renderer function the container element accepts
      Returns:
      the context of the rendering, that can be used by the components to provide extra customization

    • 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.