org.eclipse.scada.da.client

Class DataItem

java.lang.Object

java.util.Observable

org.eclipse.scada.da.client.DataItem

Direct Known Subclasses:

AsyncDataItem

public class DataItem
extends Observable

Constructor Summary

Constructors

Constructor and Description
DataItem(String itemId) create a new data item structure.
DataItem(String itemId, ItemManager itemManager) create a new data item structure.

Method Summary

Modifier and Type	Method and Description
void	addPropertyChangeListener(PropertyChangeListener listener)
void	addPropertyChangeListener(String propertyName, PropertyChangeListener listener)
Map<String,Variant>	getAttributes() Deprecated. You should use getSnapshotValue() instead to get a consistent value
String	getItemId() Get the item ID
DataItemValue	getSnapshotValue() Get the complete state of the current data item in an atomic operation
Throwable	getSubscriptionError() Deprecated. You should use getSnapshotValue() instead to get a consistent value
SubscriptionState	getSubscriptionState() Deprecated. You should use getSnapshotValue() instead to get a consistent value
protected void	handlePerformNotifyDataChange(Variant value, Map<String,Variant> attributes, boolean cache)
protected void	handlePerformNotifySubscriptionChange(SubscriptionState subscriptionState, Throwable subscriptionError)
protected void	performNotifyDataChange(Variant value, Map<String,Variant> attributes, boolean cache)
protected void	performNotifySubscriptionChange(SubscriptionState subscriptionState, Throwable subscriptionError)
void	register(ItemManager itemManager)
void	removePropertyChangeListener(PropertyChangeListener listener)
void	removePropertyChangeListener(String propertyName, PropertyChangeListener listener)
void	unregister() Unregister from the currently registered item manager

Methods inherited from class java.util.Observable

addObserver, clearChanged, countObservers, deleteObserver, deleteObservers, hasChanged, notifyObservers, notifyObservers, setChanged

Methods inherited from class java.lang.Object

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

Constructor Detail

DataItem

public DataItem(String itemId)

create a new data item structure.

Note that the item is initially unconnected

Parameters:

itemId - the id of the item to register later

DataItem

public DataItem(String itemId,
                ItemManager itemManager)

create a new data item structure.

Note that the item is initially connected to the item manager provided. You must call unregister() when you want to clear the subscription with the item on the server.

Parameters:

itemId - the id of the item to register

itemManager - the item manager to which the item will register

Method Detail

register

public void register(ItemManager itemManager)

unregister

public void unregister()

Unregister from the currently registered item manager

handlePerformNotifyDataChange

protected void handlePerformNotifyDataChange(Variant value,
                                             Map<String,Variant> attributes,
                                             boolean cache)

performNotifyDataChange

protected void performNotifyDataChange(Variant value,
                                       Map<String,Variant> attributes,
                                       boolean cache)

handlePerformNotifySubscriptionChange

protected void handlePerformNotifySubscriptionChange(SubscriptionState subscriptionState,
                                                     Throwable subscriptionError)

performNotifySubscriptionChange

protected void performNotifySubscriptionChange(SubscriptionState subscriptionState,
                                               Throwable subscriptionError)

getSnapshotValue

public DataItemValue getSnapshotValue()

Get the complete state of the current data item in an atomic operation

Returns:

the current state of the data item

getAttributes

@Deprecated
public Map<String,Variant> getAttributes()

Deprecated. You should use getSnapshotValue() instead to get a consistent value

Fetch the current cached attributes. Note: The returned object may not be modified!

Returns:

the current attributes

getSubscriptionState

@Deprecated
public SubscriptionState getSubscriptionState()

Deprecated. You should use getSnapshotValue() instead to get a consistent value

Get the subscription state

Returns:

the subscription state

getItemId

public String getItemId()

Get the item ID

Returns:

the item Id

getSubscriptionError

@Deprecated
public Throwable getSubscriptionError()

Deprecated. You should use getSnapshotValue() instead to get a consistent value

Get the subscription error or null if there was none

Returns:

the subscription error

addPropertyChangeListener

public void addPropertyChangeListener(PropertyChangeListener listener)

addPropertyChangeListener

public void addPropertyChangeListener(String propertyName,
                                      PropertyChangeListener listener)

removePropertyChangeListener

public void removePropertyChangeListener(PropertyChangeListener listener)

removePropertyChangeListener

public void removePropertyChangeListener(String propertyName,
                                         PropertyChangeListener listener)