com.google.gwt.view.client

Class AbstractDataProvider<T>

java.lang.Object

com.google.gwt.view.client.AbstractDataProvider<T>

Type Parameters:

T - the data type of records in the list

All Implemented Interfaces:

ProvidesKey<T>

Direct Known Subclasses:

AsyncDataProvider, ListDataProvider

public abstract class AbstractDataProvider<T>
extends Object
implements ProvidesKey<T>

A base implementation of a data source for HasData implementations.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractDataProvider() Construct an AbstractDataProvider without a key provider.
protected	AbstractDataProvider(ProvidesKey<T> keyProvider) Construct an AbstractDataProvider with a given key provider.

Method Summary

Modifier and Type	Method and Description
void	addDataDisplay(HasData<T> display) Adds a data display to this adapter.
Set<HasData<T>>	getDataDisplays() Get the set of displays currently assigned to this adapter.
Object	getKey(T item) Get the key for a list item.
ProvidesKey<T>	getKeyProvider() Get the ProvidesKey that provides keys for list items.
Range[]	getRanges() Get the current ranges of all displays.
protected abstract void	onRangeChanged(HasData<T> display) Called when a display changes its range of interest.
void	removeDataDisplay(HasData<T> display) Remove the given data display.
protected void	updateRowCount(int count, boolean exact) Inform the displays of the total number of items that are available.
protected void	updateRowData(HasData<T> display, int start, List<T> values) Informs a single display of new data.
protected void	updateRowData(int start, List<T> values) Inform the displays of the new data.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, toString

Constructor Detail

AbstractDataProvider

protected AbstractDataProvider()

Construct an AbstractDataProvider without a key provider.

AbstractDataProvider

protected AbstractDataProvider(ProvidesKey<T> keyProvider)

Construct an AbstractDataProvider with a given key provider.

Parameters:

keyProvider - a ProvidesKey object

Method Detail

addDataDisplay

public void addDataDisplay(HasData<T> display)

Adds a data display to this adapter. The current range of interest of the display will be populated with data.

Parameters:

display - a HasData.

getDataDisplays

public Set<HasData<T>> getDataDisplays()

Get the set of displays currently assigned to this adapter.

Returns:

the set of HasData

getKey

public Object getKey(T item)

Get the key for a list item. The default implementation returns the item itself.

Specified by:

getKey in interface ProvidesKey<T>

Parameters:

item - the list item

Returns:

the key that represents the item

getKeyProvider

public ProvidesKey<T> getKeyProvider()

Get the ProvidesKey that provides keys for list items.

Returns:

the ProvidesKey

getRanges

public Range[] getRanges()

Get the current ranges of all displays.

Returns:

the ranges

removeDataDisplay

public void removeDataDisplay(HasData<T> display)

Remove the given data display.

Parameters:

display - a HasData instance

Throws:

IllegalStateException - if the display is not present

onRangeChanged

protected abstract void onRangeChanged(HasData<T> display)

Called when a display changes its range of interest.

Parameters:

display - the display whose range has changed

updateRowCount

protected void updateRowCount(int count,
                              boolean exact)

Inform the displays of the total number of items that are available.

Parameters:

count - the new total row count

exact - true if the count is exact, false if it is an estimate

updateRowData

protected void updateRowData(int start,
                             List<T> values)

Inform the displays of the new data.

Parameters:

start - the start index

values - the data values

updateRowData

protected void updateRowData(HasData<T> display,
                             int start,
                             List<T> values)

Informs a single display of new data.

Parameters:

display - the display to be updated

start - the start index

values - the data values