org.eclipse.scada.da.server.common

Interface DataItem

All Known Implementing Classes:

ArduinoDataItem, AttributeWriteHandlerItem, DataItemBase, DataItemBaseChained, DataItemCommand, DataItemInput, DataItemInputChained, DataItemInputCommon, DataItemInputOutputChained, DataItemOutput, DataItemOutputChained, DataItemTargetImpl, DataItemTest1, FactoryMemoryCell, MemoryCellItem, MemoryChainedItem, MemoryDataItem, MemoryDeviceDataitem, MemoryItemChained, PlainFileDataItem, PlainFileDataItem, ProxyDataItem, ScheduledDataItem, ScheduledDataItem, StockQuoteItem, SuspendItem, TestItem1, TestItem2, TimeDataItem, TimeDataItem, TimeDataItem, WriteDelayItem, WriteHandlerItem

public interface DataItem

Method Summary

Methods

Modifier and Type	Method and Description
Map<String,Variant>	getAttributes()
DataItemInformation	getInformation()
NotifyFuture<Variant>	readValue() The read operation of a data item.
void	setListener(ItemListener listener) Sets the listener for this item.
NotifyFuture<WriteAttributeResults>	startSetAttributes(Map<String,Variant> attributes, OperationParameters operationParameters) Start the write attributes operation
NotifyFuture<WriteResult>	startWriteValue(Variant value, OperationParameters operationParameters) The write operation of a data item.

Method Detail

getInformation

DataItemInformation getInformation()

readValue

NotifyFuture<Variant> readValue()
                                throws InvalidOperationException

The read operation of a data item.

Returns:

The value read from the subsystem.

Throws:

InvalidOperationException - Raised if "read" is not a valid operation for this item

getAttributes

Map<String,Variant> getAttributes()

setListener

void setListener(ItemListener listener)

Sets the listener for this item. Set by the controller to which this item is registered. The item has to use the listener provided.

Parameters:

listener - The listener to use or null to disable notification

startWriteValue

NotifyFuture<WriteResult> startWriteValue(Variant value,
                                        OperationParameters operationParameters)

The write operation of a data item.

Parameters:

session - The user session

value - The value to write to the subsystem

operationParameters -

Returns:

the future to the operation

Throws:

InvalidOperationException - Raised if "write" is not a valid operation for this item

NullValueException - Raised if a null value was passed but the subsystem does not allow null values to be written

NotConvertableException - Raised if a value was passed that cannot be converted in a variant type suitable for the subsystem

OperationException - Raised if the value could not be written due to some subsystem error

startSetAttributes

NotifyFuture<WriteAttributeResults> startSetAttributes(Map<String,Variant> attributes,
                                                     OperationParameters operationParameters)

Start the write attributes operation

Parameters:

attributes - attributes to set

session - The user session

operationParameters -

Returns:

the future to the operation