T - the data type of records in the listpublic abstract class AsyncDataProvider<T> extends AbstractDataProvider<T>
AbstractDataProvider that allows the data to be
modified.
public class AsyncDataProviderExample implements EntryPoint {
/**
* A custom {@link AsyncDataProvider}.
*/
private static class MyDataProvider extends AsyncDataProvider<String> {
/**
* {@link #onRangeChanged(HasData)} is called when the table requests a new
* range of data. You can push data back to the displays using
* {@link #updateRowData(int, List)}.
*/
@Override
protected void onRangeChanged(HasData<String> display) {
// Get the new range.
final Range range = display.getVisibleRange();
/*
* Query the data asynchronously. If you are using a database, you can
* make an RPC call here. We'll use a Timer to simulate a delay.
*/
new Timer() {
@Override
public void run() {
// We are creating fake data. Normally, the data will come from a
// server.
int start = range.getStart();
int length = range.getLength();
List<String> newData = new ArrayList<String>();
for (int i = start; i < start + length; i++) {
newData.add("Item " + i);
}
// Push the data to the displays. AsyncDataProvider will only update
// displays that are within range of the data.
updateRowData(start, newData);
}
}.schedule(3000);
}
}
public void onModuleLoad() {
// Create a CellList.
CellList<String> cellList = new CellList<String>(new TextCell());
// Create a data provider.
MyDataProvider dataProvider = new MyDataProvider();
// Add the cellList to the dataProvider.
dataProvider.addDataDisplay(cellList);
// Create paging controls.
SimplePager pager = new SimplePager();
pager.setDisplay(cellList);
// Add the widgets to the root panel.
VerticalPanel vPanel = new VerticalPanel();
vPanel.add(pager);
vPanel.add(cellList);
RootPanel.get().add(vPanel);
}
}
| Modifier | Constructor and Description |
|---|---|
protected |
AsyncDataProvider()
Constructs an AsyncDataProvider without a key provider.
|
protected |
AsyncDataProvider(ProvidesKey<T> keyProvider)
Constructs an AsyncDataProvider with the given key provider.
|
| Modifier and Type | Method and Description |
|---|---|
void |
updateRowCount(int size,
boolean exact)
Inform the displays of the total number of items that are available.
|
void |
updateRowData(int start,
java.util.List<T> values)
Inform the displays of the new data.
|
addDataDisplay, getDataDisplays, getKey, getKeyProvider, getRanges, onRangeChanged, removeDataDisplay, updateRowDataprotected AsyncDataProvider()
protected AsyncDataProvider(ProvidesKey<T> keyProvider)
keyProvider - an instance of ProvidesKeypublic void updateRowCount(int size,
boolean exact)
AbstractDataProviderupdateRowCount in class AbstractDataProvider<T>size - the new total row countexact - true if the count is exact, false if it is an estimatepublic void updateRowData(int start,
java.util.List<T> values)
AbstractDataProviderupdateRowData in class AbstractDataProvider<T>start - the start indexvalues - the data values