com.vaadin.data.provider.

java.lang.Object
- com.vaadin.server.AbstractClientConnector
- - com.vaadin.server.AbstractExtension
  - - com.vaadin.data.provider.DataCommunicator<T>

Type Parameters:

T - the bean type

All Implemented Interfaces:

MethodEventSource, ClientConnector, Extension, Connector, Serializable

Direct Known Subclasses:

HierarchicalDataCommunicator
```
public class DataCommunicator<T>
extends AbstractExtension
```
DataProvider base class. This class is the base for all DataProvider communication implementations. It uses DataGenerators to write JsonObjects representing each data object to be sent to the client-side.

Since:

8.0

See Also:

Serialized Form

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`protected class`	`DataCommunicator.ActiveDataHandler`	A class for handling currently active data and dropping data that is no longer needed.
`protected class`	`DataCommunicator.SimpleDataRequestRpc`	Simple implementation of collection data provider communication.

Nested classes/interfaces inherited from interface com.vaadin.server.ClientConnector
ClientConnector.AttachEvent, ClientConnector.AttachListener, ClientConnector.ConnectorErrorEvent, ClientConnector.DetachEvent, ClientConnector.DetachListener

Field Summary

Fields
Modifier and Type Field Description

protected boolean reset
Boolean for pending hard reset.

Constructor Summary

Constructors
Constructor Description

DataCommunicator()

Method Summary

All Methods
Modifier and Type	Method	Description
`void`	`addDataGenerator(DataGenerator<T> generator)`	Adds a data generator to this data communicator.
`void`	`attach()`	Notifies the connector that it is connected to a VaadinSession (and therefore also to a UI).
`void`	`beforeClientResponse(boolean initial)`	Initially and in the case of a reset all data should be pushed to the client.
`protected DataKeyMapper<T>`	`createKeyMapper(ValueProvider<T,Object> identifierGetter)`	Creates a `DataKeyMapper` to use with this DataCommunicator.
`protected DataRequestRpc`	`createRpc()`	Creates a `DataRequestRpc` used with this `DataCommunicator`.
`void`	`detach()`	Notifies the connector that it is detached from its VaadinSession.
`protected void`	`dropAllData()`	Drops all data associated with this data communicator.
`List<T>`	`fetchItemsWithRange(int offset, int limit)`	Fetches a list of items from the DataProvider.
`protected DataCommunicator.ActiveDataHandler`	`getActiveDataHandler()`	Returns the active data handler.
`List<QuerySortOrder>`	`getBackEndSorting()`	Returns the `QuerySortOrder` to use with backend sorting.
`protected DataCommunicatorClientRpc`	`getClientRpc()`	Get the client rpc interface for this data communicator.
`protected elemental.json.JsonObject`	`getDataObject(T data)`	Creates the JsonObject for given data object.
`DataProvider<T,?>`	`getDataProvider()`	Gets the current data provider from this DataCommunicator.
`int`	`getDataProviderSize()`	Getter method for finding the size of DataProvider.
`protected Object`	`getFilter()`	Get the object used for filtering in this data communicator.
`Comparator<T>`	`getInMemorySorting()`	Returns the `Comparator` to use with in-memory sorting.
`DataKeyMapper<T>`	`getKeyMapper()`	Gets the `DataKeyMapper` used by this `DataCommunicator`.
`protected int`	`getMaximumAllowedRows()`	Get the maximum allowed rows to be fetched in one query.
`int`	`getMinPushSize()`	Get minimum size of data which will be sent to the client when data source is set.
`protected Range`	`getPushRows()`	Get the current range of rows to push in the next response.
`protected DataCommunicatorState`	`getState()`	Returns the shared state for this connector.
`protected DataCommunicatorState`	`getState(boolean markAsDirty)`	Returns the shared state for this connector.
`protected Set<T>`	`getUpdatedData()`	Returns the currently set updated data.
`protected void`	`onDropRows(elemental.json.JsonArray keys)`	Triggered when rows have been dropped from the client side cache.
`protected void`	`onRequestRows(int firstRowIndex, int numberOfRows, int firstCachedRowIndex, int cacheSize)`	Request the given rows to be available on the client side.
`protected void`	`pushData(int firstIndex, List<T> data)`	Sends given collection of data objects to the client-side.
`void`	`refresh(T data)`	Informs the DataProvider that a data object has been updated.
`void`	`removeDataGenerator(DataGenerator<T> generator)`	Removes a data generator from this data communicator.
`void`	`reset()`	Method for internal reset from a change in the component, requiring a full data update.
`protected void`	`sendDataToClient(boolean initial)`	Send the needed data and updates to the client side.
`void`	`setBackEndSorting(List<QuerySortOrder> sortOrder)`	Sets the `QuerySortOrder`s to use with backend sorting.
`void`	`setBackEndSorting(List<QuerySortOrder> sortOrder, boolean immediateReset)`	Sets the `QuerySortOrder`s to use with backend sorting.
`protected void`	`setDataProvider(DataProvider<T,?> dataProvider)`	Sets a new `DataProvider` and refreshes all the internal structures.
`<F> SerializableConsumer<F>`	`setDataProvider(DataProvider<T,F> dataProvider, F initialFilter)`	Sets the current data provider for this DataCommunicator.
`protected <F> void`	`setFilter(F filter)`	Sets the filter for this DataCommunicator.
`void`	`setInMemorySorting(Comparator<T> comparator)`	Sets the `Comparator` to use with in-memory sorting.
`void`	`setInMemorySorting(Comparator<T> comparator, boolean immediateReset)`	Sets the `Comparator` to use with in-memory sorting.
`void`	`setMaximumAllowedRows(int maximumAllowedRows)`	Set the maximum allowed rows to be fetched in one query.
`void`	`setMinPushSize(int size)`	Set minimum size of data which will be sent to the client when data source is set.
`protected void`	`setPushRows(Range pushRows)`	Set the range of rows to push for next response.

Methods inherited from class com.vaadin.server.AbstractExtension
extend, getParent, getSupportedParentType, remove, setParent

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.vaadin.server.ClientConnector
addAttachListener, addDetachListener, encodeState, getErrorHandler, getExtensions, getRpcManager, getStateType, getUI, handleConnectorRequest, isAttached, isConnectorEnabled, markAsDirty, markAsDirtyRecursive, removeAttachListener, removeDetachListener, removeExtension, requestRepaint, requestRepaintAll, retrievePendingRpcCalls, setErrorHandler

Methods inherited from interface com.vaadin.shared.Connector
getConnectorId

- Field Detail
  - reset
```
protected boolean reset
```
    Boolean for pending hard reset.
- Constructor Detail
  - DataCommunicator
```
public DataCommunicator()
```
- Method Detail
  - attach
```
public void attach()
```
    Description copied from interface: ClientConnector
    
    Notifies the connector that it is connected to a VaadinSession (and therefore also to a UI).
    The caller of this method is Component.setParent(HasComponents) if the parent is itself already attached to the session. If not, the parent will call the ClientConnector.attach() for all its children when it is attached to the session. This method is always called before the connector's data is sent to the client-side for the first time.
    
    The attachment logic is implemented in AbstractClientConnector.
    
    Specified by:
    
    attach in interface ClientConnector
    
    Overrides:
    
    attach in class AbstractClientConnector
  - detach
```
public void detach()
```
    Description copied from class: AbstractClientConnector
    
    Notifies the connector that it is detached from its VaadinSession.
    The caller of this method is Component.setParent(HasComponents) if the parent is in the session. When the parent is detached from the session it is its responsibility to call ClientConnector.detach() for each of its children.
    
    The AbstractClientConnector.getSession() and AbstractClientConnector.getUI() methods might return null after this method is called.
    
    Specified by:
    
    detach in interface ClientConnector
    
    Overrides:
    
    detach in class AbstractClientConnector
  - setPushRows
```
protected void setPushRows(Range pushRows)
```
    Set the range of rows to push for next response.
    
    Parameters:
    
    pushRows -
    
    Since:
    
    8.0.6
  - getPushRows
```
protected Range getPushRows()
```
    Get the current range of rows to push in the next response.
    
    Returns:
    
    the range of rows to push
    
    Since:
    
    8.0.6
  - getFilter
```
protected Object getFilter()
```
    Get the object used for filtering in this data communicator.
    
    Returns:
    
    the filter object of this data communicator
    
    Since:
    
    8.0.6
  - getClientRpc
```
protected DataCommunicatorClientRpc getClientRpc()
```
    Get the client rpc interface for this data communicator.
    
    Returns:
    
    the client rpc interface for this data communicator
    
    Since:
    
    8.0.6
  - onRequestRows
```
protected void onRequestRows(int firstRowIndex,
                             int numberOfRows,
                             int firstCachedRowIndex,
                             int cacheSize)
```
    Request the given rows to be available on the client side.
    
    Parameters:
    
    firstRowIndex - the index of the first requested row
    
    numberOfRows - the number of requested rows
    
    firstCachedRowIndex - the index of the first cached row
    
    cacheSize - the number of cached rows
    
    Since:
    
    8.0.6
  - getMaximumAllowedRows
```
protected int getMaximumAllowedRows()
```
    Get the maximum allowed rows to be fetched in one query.
    
    Returns:
    
    Maximum allowed rows for one query.
    
    Since:
    
    8.14.1
  - setMaximumAllowedRows
```
public void setMaximumAllowedRows(int maximumAllowedRows)
```
    Set the maximum allowed rows to be fetched in one query.
    
    Parameters:
    
    maximumAllowedRows - Maximum allowed rows for one query.
    
    Since:
    
    8.15
  - onDropRows
```
protected void onDropRows(elemental.json.JsonArray keys)
```
    Triggered when rows have been dropped from the client side cache.
    
    Parameters:
    
    keys - the keys of the rows that have been dropped
    
    Since:
    
    8.0.6
  - beforeClientResponse
```
public void beforeClientResponse(boolean initial)
```
    Initially and in the case of a reset all data should be pushed to the client.
    
    Specified by:
    
    beforeClientResponse in interface ClientConnector
    
    Overrides:
    
    beforeClientResponse in class AbstractClientConnector
    
    Parameters:
    
    initial - true if the client-side connector will be created and initialized after this method has been invoked. false if there is already an initialized client-side connector.
  - sendDataToClient
```
protected void sendDataToClient(boolean initial)
```
    Send the needed data and updates to the client side.
    
    Parameters:
    
    initial - true if initial data load, false if not
    
    Since:
    
    8.0.6
  - fetchItemsWithRange
```
public List<T> fetchItemsWithRange(int offset,
                                   int limit)
```
    Fetches a list of items from the DataProvider.
    
    Parameters:
    
    offset - the starting index of the range
    
    limit - the max number of results
    
    Returns:
    
    the list of items in given range
    
    Since:
    
    8.1
  - addDataGenerator
```
public void addDataGenerator(DataGenerator<T> generator)
```
    Adds a data generator to this data communicator. Data generators can be used to insert custom data to the rows sent to the client. If the data generator is already added, does nothing.
    
    Parameters:
    
    generator - the data generator to add, not null
  - removeDataGenerator
```
public void removeDataGenerator(DataGenerator<T> generator)
```
    Removes a data generator from this data communicator. If there is no such data generator, does nothing.
    
    Parameters:
    
    generator - the data generator to remove, not null
  - getKeyMapper
```
public DataKeyMapper<T> getKeyMapper()
```
    Gets the DataKeyMapper used by this DataCommunicator. Key mapper can be used to map keys sent to the client-side back to their respective data objects.
    
    Returns:
    
    key mapper
  - pushData
```
protected void pushData(int firstIndex,
                        List<T> data)
```
    Sends given collection of data objects to the client-side.
    
    Parameters:
    
    firstIndex - first index of pushed data
    
    data - data objects to send as an iterable
  - getDataObject
```
protected elemental.json.JsonObject getDataObject(T data)
```
    Creates the JsonObject for given data object. This method calls all data generators for it.
    
    Parameters:
    
    data - data object to be made into a json object
    
    Returns:
    
    json object representing the data object
  - getActiveDataHandler
```
protected DataCommunicator.ActiveDataHandler getActiveDataHandler()
```
    Returns the active data handler.
    
    Returns:
    
    the active data handler
    
    Since:
    
    8.0.6
  - dropAllData
```
protected void dropAllData()
```
    Drops all data associated with this data communicator.
  - reset
```
public void reset()
```
    Method for internal reset from a change in the component, requiring a full data update.
  - refresh
```
public void refresh(T data)
```
    Informs the DataProvider that a data object has been updated.
    
    Parameters:
    
    data - updated data object; not null
  - getUpdatedData
```
protected Set<T> getUpdatedData()
```
    Returns the currently set updated data.
    
    Returns:
    
    the set of data that should be updated on the next response
    
    Since:
    
    8.0.6
  - setInMemorySorting
```
public void setInMemorySorting(Comparator<T> comparator,
                               boolean immediateReset)
```
    Sets the Comparator to use with in-memory sorting.
    
    Parameters:
    
    comparator - comparator used to sort data
    
    immediateReset - true if an internal reset should be performed immediately after updating the comparator (unless full reset is already pending), false if you are going to trigger reset separately later
  - setInMemorySorting
```
public void setInMemorySorting(Comparator<T> comparator)
```
    Sets the Comparator to use with in-memory sorting.
    
    Parameters:
    
    comparator - comparator used to sort data
  - getInMemorySorting
```
public Comparator<T> getInMemorySorting()
```
    Returns the Comparator to use with in-memory sorting.
    
    Returns:
    
    comparator used to sort data
    
    Since:
    
    8.0.6
  - setBackEndSorting
```
public void setBackEndSorting(List<QuerySortOrder> sortOrder,
                              boolean immediateReset)
```
    Sets the QuerySortOrders to use with backend sorting.
    
    Parameters:
    
    sortOrder - list of sort order information to pass to a query
    
    immediateReset - true if an internal reset should be performed immediately after updating the comparator (unless full reset is already pending), false if you are going to trigger reset separately later
  - setBackEndSorting
```
public void setBackEndSorting(List<QuerySortOrder> sortOrder)
```
    Sets the QuerySortOrders to use with backend sorting.
    
    Parameters:
    
    sortOrder - list of sort order information to pass to a query
  - getBackEndSorting
```
public List<QuerySortOrder> getBackEndSorting()
```
    Returns the QuerySortOrder to use with backend sorting.
    
    Returns:
    
    an unmodifiable list of sort order information to pass to a query
    
    Since:
    
    8.0.6
  - createKeyMapper
```
protected DataKeyMapper<T> createKeyMapper(ValueProvider<T,Object> identifierGetter)
```
    Creates a DataKeyMapper to use with this DataCommunicator.
    This method is called from the constructor.
    
    Parameters:
    
    identifierGetter - has to return a unique key for every bean, and the returned key has to follow general hashCode() and equals() contract, see Object.hashCode() for details.
    
    Returns:
    
    key mapper
    
    Since:
    
    8.1
  - createRpc
```
protected DataRequestRpc createRpc()
```
    Creates a DataRequestRpc used with this DataCommunicator.
    This method is called from the constructor.
    
    Returns:
    
    data request rpc implementation
  - getDataProvider
```
public DataProvider<T,?> getDataProvider()
```
    Gets the current data provider from this DataCommunicator.
    
    Returns:
    
    the data provider
  - setDataProvider
```
public <F> SerializableConsumer<F> setDataProvider(DataProvider<T,F> dataProvider,
                                                   F initialFilter)
```
    Sets the current data provider for this DataCommunicator.
    The returned consumer can be used to set some other filter value that should be included in queries sent to the data provider. It is only valid until another data provider is set.
    
    Type Parameters:
    
    F - the filter type
    
    Parameters:
    
    dataProvider - the data provider to set, not null
    
    initialFilter - the initial filter value to use, or null to not use any initial filter value
    
    Returns:
    
    a consumer that accepts a new filter value to use
  - setFilter
```
protected <F> void setFilter(F filter)
```
    Sets the filter for this DataCommunicator. This method is used by user through the consumer method from setDataProvider(com.vaadin.data.provider.DataProvider<T, F>, F) and should not be called elsewhere.
    
    Type Parameters:
    
    F - the filter type
    
    Parameters:
    
    filter - the filter
    
    Since:
    
    8.1
  - setMinPushSize
```
public void setMinPushSize(int size)
```
    Set minimum size of data which will be sent to the client when data source is set.
    Server doesn't send all data from data source to the client. It sends some initial chunk of data (whose size is determined as minimum between size parameter of this method and data size). Client decides whether it is able to show more data and request server to send more data (next chunk).
    When component is disabled then client cannot communicate to the server side (by design, because of security reasons). It means that client will get only initial chunk of data whose size is set here.
    
    Parameters:
    
    size - the size of initial data to send to the client
  - getMinPushSize
```
public int getMinPushSize()
```
    Get minimum size of data which will be sent to the client when data source is set.
    
    Returns:
    
    current minimum push size of initial data chunk which is sent to the client when data source is set
    
    See Also:
    
    setMinPushSize(int)
  - getDataProviderSize
```
public int getDataProviderSize()
```
    Getter method for finding the size of DataProvider. Can be overridden by a subclass that uses a specific type of DataProvider and/or query.
    
    Returns:
    
    the size of data provider with current filter
  - getState
```
protected DataCommunicatorState getState(boolean markAsDirty)
```
    Description copied from class: AbstractClientConnector
    
    Returns the shared state for this connector.
    
    Overrides:
    
    getState in class AbstractClientConnector
    
    Parameters:
    
    markAsDirty - true if the connector should automatically be marked dirty, false otherwise
    
    Returns:
    
    The shared state for this connector. Never null.
    
    See Also:
    
    AbstractClientConnector.getState()
  - getState
```
protected DataCommunicatorState getState()
```
    Description copied from class: AbstractClientConnector
    
    Returns the shared state for this connector. The shared state object is shared between the server connector and the client connector. Changes are only communicated from the server to the client and not in the other direction.
    As a side effect, marks the connector dirty so any changes done to the state will be sent to the client. Use getState(false) to avoid marking the connector as dirty.
    
    Overrides:
    
    getState in class AbstractClientConnector
    
    Returns:
    
    The shared state for this connector. Never null.
  - setDataProvider
```
protected void setDataProvider(DataProvider<T,?> dataProvider)
```
    Sets a new DataProvider and refreshes all the internal structures.
    
    Parameters:
    
    dataProvider -
    
    Since:
    
    8.1

com.vaadin.data.provider.

Class DataCommunicator<T>

Nested Class Summary

Nested classes/interfaces inherited from interface com.vaadin.server.ClientConnector

Field Summary

Constructor Summary

Method Summary

Methods inherited from class com.vaadin.server.AbstractExtension

Methods inherited from class com.vaadin.server.AbstractClientConnector

Methods inherited from class java.lang.Object

Methods inherited from interface com.vaadin.server.ClientConnector

Methods inherited from interface com.vaadin.shared.Connector

Field Detail

reset

Constructor Detail

DataCommunicator

Method Detail

attach

detach

setPushRows

getPushRows

getFilter

getClientRpc

onRequestRows

getMaximumAllowedRows

setMaximumAllowedRows

onDropRows

beforeClientResponse

sendDataToClient

fetchItemsWithRange

addDataGenerator

removeDataGenerator

getKeyMapper

pushData

getDataObject

getActiveDataHandler

dropAllData

reset

refresh

getUpdatedData

setInMemorySorting

setInMemorySorting

getInMemorySorting

setBackEndSorting

setBackEndSorting

getBackEndSorting

createKeyMapper

createRpc

getDataProvider

setDataProvider

setFilter

setMinPushSize

getMinPushSize

getDataProviderSize

getState

getState

setDataProvider