Package com.vaadin.client.widget.escalator

Interface EscalatorUpdater

All Known Implementing Classes:

Grid.BodyUpdater, Grid.StaticSectionUpdater

public interface EscalatorUpdater

An interface that allows client code to define how a certain row in Escalator will be displayed. The contents of an escalator's header, body and footer are rendered by their respective updaters.

The updater is responsible for internally handling all remote communication, should the displayed data need to be fetched remotely.

This has a similar function to Grid's Renderers , although they operate on different abstraction levels.

Since:

7.4

Author:

Vaadin Ltd

See Also:

RowContainer.setEscalatorUpdater(EscalatorUpdater), Escalator.getHeader(), Escalator.getBody(), Escalator.getFooter(), Renderer

Field Summary

Fields

Modifier and Type	Field	Description
static EscalatorUpdater	NULL	An EscalatorUpdater that doesn't render anything.

Method Summary

Modifier and Type	Method	Description
void	postAttach(Row row, Iterable<FlyweightCell> attachedCells)	Called after attaching new cells to the escalator.
void	postDetach(Row row, Iterable<FlyweightCell> detachedCells)	Called after detaching cells from the escalator.
void	preAttach(Row row, Iterable<FlyweightCell> cellsToAttach)	Called before attaching new cells to the escalator.
void	preDetach(Row row, Iterable<FlyweightCell> cellsToDetach)	Called before detaching cells from the escalator.
void	update(Row row, Iterable<FlyweightCell> cellsToUpdate)	Renders a row contained in a row container.

Field Detail

NULL

static final EscalatorUpdater NULL

An EscalatorUpdater that doesn't render anything.

Method Detail

update

void update(Row row,
            Iterable<FlyweightCell> cellsToUpdate)

Renders a row contained in a row container.

Note: If rendering of cells is deferred (e.g. because asynchronous data retrieval), this method is responsible for explicitly displaying some placeholder data (empty content is valid). Because the cells (and rows) in an escalator are recycled, failing to reset a cell's presentation will lead to wrong data being displayed in the escalator.

For performance reasons, the escalator will never autonomously clear any data in a cell.

Parameters:

row - Information about the row that is being updated. Note: You should not store nor reuse this reference.

cellsToUpdate - A collection of cells that need to be updated. Note: You should neither store nor reuse the reference to the iterable, nor to the individual cells.

preAttach

void preAttach(Row row,
               Iterable<FlyweightCell> cellsToAttach)

Called before attaching new cells to the escalator.

Parameters:

row - Information about the row to which the cells will be added. Note: You should not store nor reuse this reference.

cellsToAttach - A collection of cells that are about to be attached. Note: You should neither store nor reuse the reference to the iterable, nor to the individual cells.

postAttach

void postAttach(Row row,
                Iterable<FlyweightCell> attachedCells)

Called after attaching new cells to the escalator.

Parameters:

row - Information about the row to which the cells were added. Note: You should not store nor reuse this reference.

attachedCells - A collection of cells that were attached. Note: You should neither store nor reuse the reference to the iterable, nor to the individual cells.

preDetach

void preDetach(Row row,
               Iterable<FlyweightCell> cellsToDetach)

Called before detaching cells from the escalator.

Parameters:

row - Information about the row from which the cells will be removed. Note: You should not store nor reuse this reference.

cellsToAttach - A collection of cells that are about to be detached. Note: You should neither store nor reuse the reference to the iterable, nor to the individual cells.

postDetach

void postDetach(Row row,
                Iterable<FlyweightCell> detachedCells)

Called after detaching cells from the escalator.

Parameters:

row - Information about the row from which the cells were removed. Note: You should not store nor reuse this reference.

attachedCells - A collection of cells that were detached. Note: You should neither store nor reuse the reference to the iterable, nor to the individual cells.