com.vaadin.client.connectors.data

Class DataCommunicatorConnector.VaadinDataSource

java.lang.Object

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

com.vaadin.client.connectors.data.DataCommunicatorConnector.VaadinDataSource

All Implemented Interfaces:

DataSource<elemental.json.JsonObject>

Enclosing class:

DataCommunicatorConnector

public class DataCommunicatorConnector.VaadinDataSource
extends AbstractRemoteDataSource<elemental.json.JsonObject>

Client-side DataSource implementation to be used with DataCommunicator.

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	VaadinDataSource()

Method Summary

Modifier and Type	Method and Description
String	getRowKey(elemental.json.JsonObject row) Gets a stable key for the row object.
protected void	onDropFromCache(int rowIndex, elemental.json.JsonObject removed) 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	updateRowData(elemental.json.JsonObject row) Updates row data based on row key.

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

addDataChangeHandler, canFetchData, ensureAvailability, getCachedRange, getHandle, getRequestedAvailability, getRow, indexOf, indexOfKey, insertRowData, isPinned, isWaitingForData, onDropFromCache, pinHandle, removeRowData, resetDataAndSize, setCacheStrategy, setRowData, size, unpinHandle

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.vaadin.client.data.DataSource

addDataChangeHandler

Constructor Detail

VaadinDataSource

protected VaadinDataSource()

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

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

onDropFromCache

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

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

removed - the removed row object

updateRowData

protected void updateRowData(elemental.json.JsonObject row)

Updates row data based on row key.

Parameters:

row - new row object