com.vaadin.client.connectors

Class RpcDataSourceConnector.RpcDataSource

java.lang.Object

com.vaadin.client.data.AbstractRemoteDataSource<elemental.json.JsonObject>

com.vaadin.client.connectors.RpcDataSourceConnector.RpcDataSource

All Implemented Interfaces:

DataSource<elemental.json.JsonObject>

Enclosing class:

RpcDataSourceConnector

public class RpcDataSourceConnector.RpcDataSource
extends AbstractRemoteDataSource<elemental.json.JsonObject>

Nested Class Summary

Nested classes/interfaces inherited from class com.vaadin.client.data.AbstractRemoteDataSource

AbstractRemoteDataSource.RequestRowsCallback<T>, AbstractRemoteDataSource.RowHandleImpl

Nested classes/interfaces inherited from interface com.vaadin.client.data.DataSource

DataSource.RowHandle<T>

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	RpcDataSource()

Method Summary

Modifier and Type	Method and Description
protected boolean	canFetchData() Checks if it is possible to currently fetch data from the remote data source.
void	ensureAvailability(int firstRowIndex, int numberOfRows) Informs the data source that data for the given range is needed.
DataSource.RowHandle<elemental.json.JsonObject>	getHandleByKey(Object key)
String	getRowKey(elemental.json.JsonObject row) Gets a stable key for the row object.
protected void	onDropFromCache(int rowIndex, elemental.json.JsonObject row) A hook that can be overridden to do something whenever a row has been dropped from the cache.
protected void	requestRows(int firstRowIndex, int numberOfRows, AbstractRemoteDataSource.RequestRowsCallback<elemental.json.JsonObject> callback) Triggers fetching rows from the remote data source.
protected void	setRowData(int firstRowIndex, List<elemental.json.JsonObject> rowData) Informs this data source that updated data has been sent from the server.
protected void	unpinHandle(AbstractRemoteDataSource.RowHandleImpl handle) Unpins a previously pinned row with given handle.
protected void	updateRowData(elemental.json.JsonObject row) Updates row data based on row key.

Methods inherited from class com.vaadin.client.data.AbstractRemoteDataSource

getCachedRange, getHandle, getRequestedAvailability, getRow, indexOf, indexOfKey, insertRowData, isPinned, isWaitingForData, onDropFromCache, pinHandle, removeRowData, resetDataAndSize, setCacheStrategy, setDataChangeHandler, size

Methods inherited from class java.lang.Object

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

Constructor Detail

RpcDataSource

protected RpcDataSource()

Method Detail

requestRows

protected void requestRows(int firstRowIndex,
                           int numberOfRows,
                           AbstractRemoteDataSource.RequestRowsCallback<elemental.json.JsonObject> callback)

Description copied from class: AbstractRemoteDataSource

Triggers fetching rows from the remote data source. The provided callback should be informed when the requested rows have been received.

Specified by:

requestRows in class AbstractRemoteDataSource<elemental.json.JsonObject>

Parameters:

firstRowIndex - the index of the first row to fetch

numberOfRows - the number of rows to fetch

callback - callback to inform when the requested rows are available

ensureAvailability

public void ensureAvailability(int firstRowIndex,
                               int numberOfRows)

Description copied from interface: DataSource

Informs the data source that data for the given range is needed. A data source only has one active region at a time, so calling this method discards the previously set range.

This method triggers lazy loading of data if necessary. The change handler registered using DataSource.setDataChangeHandler(DataChangeHandler) is informed when new data has been loaded.

After any possible lazy loading and updates are done, the change handler is informed that new data is available.

Specified by:

ensureAvailability in interface DataSource<elemental.json.JsonObject>

Overrides:

ensureAvailability in class AbstractRemoteDataSource<elemental.json.JsonObject>

Parameters:

firstRowIndex - the index of the first needed row

numberOfRows - the number of needed rows

getRowKey

public String getRowKey(elemental.json.JsonObject row)

Description copied from class: AbstractRemoteDataSource

Gets a stable key for the row object.

This method is a workaround for the fact that there is no means to force proper implementations for Object.hashCode() and Object.equals(Object) methods.

Since the same row object will be created several times for the same logical data, the DataSource needs a mechanism to be able to compare two objects, and figure out whether or not they represent the same data. Even if all the fields of an entity would be changed, it still could represent the very same thing (say, a person changes all of her names.)

A very usual and simple example what this could be, is an unique ID for this object that would also be stored in a database.

Specified by:

getRowKey in class AbstractRemoteDataSource<elemental.json.JsonObject>

Parameters:

row - the row object for which to get the key

Returns:

a non-null object that uniquely and consistently represents the row object

getHandleByKey

public DataSource.RowHandle<elemental.json.JsonObject> getHandleByKey(Object key)

unpinHandle

protected void unpinHandle(AbstractRemoteDataSource.RowHandleImpl handle)

Description copied from class: AbstractRemoteDataSource

Unpins a previously pinned row with given handle. This function can be overridden to do specific logic related to unpinning rows.

Overrides:

unpinHandle in class AbstractRemoteDataSource<elemental.json.JsonObject>

Parameters:

handle - row handle to unpin

setRowData

protected void setRowData(int firstRowIndex,
                          List<elemental.json.JsonObject> rowData)

Description copied from class: AbstractRemoteDataSource

Informs this data source that updated data has been sent from the server.

Overrides:

setRowData in class AbstractRemoteDataSource<elemental.json.JsonObject>

Parameters:

firstRowIndex - the index of the first received row

rowData - a list of rows, starting from firstRowIndex

updateRowData

protected void updateRowData(elemental.json.JsonObject row)

Updates row data based on row key.

Parameters:

row - new row object

Since:

7.6

onDropFromCache

protected void onDropFromCache(int rowIndex,
                               elemental.json.JsonObject row)

Description copied from class: AbstractRemoteDataSource

A hook that can be overridden to do something whenever a row has been dropped from the cache. DataSource no longer has anything in the given index.

Overrides:

onDropFromCache in class AbstractRemoteDataSource<elemental.json.JsonObject>

Parameters:

rowIndex - the index of the dropped row

row - the removed row object

canFetchData

protected boolean canFetchData()

Description copied from class: AbstractRemoteDataSource

Checks if it is possible to currently fetch data from the remote data source.

Overrides:

canFetchData in class AbstractRemoteDataSource<elemental.json.JsonObject>

Returns:

true if it is ok to try to fetch data, false if it is known that fetching data will fail and should not be tried right now.