com.prosysopc.ua.client

Class MonitoredItem

java.lang.Object

com.prosysopc.ua.MonitoredItemBase

com.prosysopc.ua.client.MonitoredItem

Direct Known Subclasses:

MonitoredDataItem, MonitoredEventItem

public abstract class MonitoredItem
extends MonitoredItemBase

Clients define MonitoredItems to subscribe to data and Events. Each MonitoredItem identifies the item to be monitored and the Subscription to use to send Notifications. The item to be monitored may be any Node Attribute.

Notifications are data structures that describe the occurrence of data changes and Events. They are packaged into NotificationMessages for transfer to the Client. The Subscription periodically sends NotificationMessages at a user-specified publishing interval, and the cycle during which these messages are sent is called a publishing cycle.

Four primary parameters are defined for MonitoredItems that tell the Server how the item is to be sampled, evaluated and reported. These parameters are the sampling interval, the monitoring mode, the filter and the queue parameter.

Field Summary

Fields

Modifier and Type	Field and Description
protected static org.slf4j.Logger	logger

Fields inherited from class com.prosysopc.ua.MonitoredItemBase

attributeId, clientHandle, dataEncoding, discardOldest, maxQueueSize, monitoredItemId, monitoringMode, nodeId, prevMonitoringMode, queueSize

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	MonitoredItem(ExpandedNodeId expandedNodeId, UnsignedInteger attributeId, MonitoringMode monitoringMode) Create a new monitored item in a subscription.
protected	MonitoredItem(NodeId nodeId, UnsignedInteger attributeId, MonitoringMode monitoringMode) Create a new monitored item in a subscription.

Method Summary

Modifier and Type	Method and Description
protected void	clearModified()
protected void	clearMonitoringModeModified()
boolean	equals(Object obj)
protected void	fireError(StatusCode newErrorCode) Triggers MonitoredItemErrorListener.onError(MonitoredItem, StatusCode), if listener set to this item.
StatusCode	getErrorCode() Item error status.
MonitoredItemErrorListener	getErrorListener() Returns the current error listener.
ExpandedNodeId	getExpandedNodeId()
StatusCode	getInitialStatus() The initial status tells if the creation of the MonitoredItem succeeded in the first createMonitoredItems.
NodeId	getNodeId()
protected String	getNodeIdAsString()
Subscription	getSubscription()
int	hashCode()
boolean	isModified()
boolean	isMonitoringModeModified()
protected void	itemChanged()
protected void	monitoringModeChanged()
protected void	setClientHandle(int i)
protected void	setErrorCode(StatusCode statusCode)
void	setErrorListener(MonitoredItemErrorListener statusListener) Sets a listener for observing when getErrorCode() changes.
protected void	setFilterResult(MonitoringFilterResult filterResult)
protected void	setMonitoredItemId(UnsignedInteger monitoredItemId)
protected void	setRevisedQueueSize(UnsignedInteger revisedQueueSize)
protected void	updateFilter() React to changes in the filter.
protected void	updateQueue() Update the queue, when it's size has changed.

Methods inherited from class com.prosysopc.ua.MonitoredItemBase

close, getAttributeId, getClientHandle, getDataEncoding, getDefaultQueueSize, getFilter, getFilterResult, getIndexRange, getMonitoredItemId, getMonitoringMode, getPrevMonitoringMode, getQueueSize, getSamplingInterval, getUserData, isDiscardOldest, setDiscardOldest, setFilter, setMonitoringMode, setQueueSize, setQueueSize, setUserData, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

logger

protected static final org.slf4j.Logger logger

Constructor Detail

MonitoredItem

protected MonitoredItem(ExpandedNodeId expandedNodeId,
                        UnsignedInteger attributeId,
                        MonitoringMode monitoringMode)

Create a new monitored item in a subscription. The item is automatically assigned the next available ClientHandle.

Parameters:

expandedNodeId - the NodeId (in ExpandedNodeId form) of the node to monitor

attributeId - the attribute to monitor

monitoringMode - the initial monitoring mode for the item. Specifies whether sampling and reporting are enabled or disabled for a MonitoredItem.

MonitoredItem

protected MonitoredItem(NodeId nodeId,
                        UnsignedInteger attributeId,
                        MonitoringMode monitoringMode)

Create a new monitored item in a subscription. The item is automatically assigned the next available ClientHandle.

Parameters:

nodeId - the NodeId of the node to monitor

attributeId - the attribute to monitor

monitoringMode - the initial monitoring mode for the item. Specifies whether sampling and reporting are enabled or disabled for a MonitoredItem.

Method Detail

equals

public boolean equals(Object obj)

Overrides:

equals in class MonitoredItemBase

getErrorCode

public StatusCode getErrorCode()

Item error status. If the item creation succeeds without a problem, the code should be StatusCode.GOOD.

Returns:

the status of the item after it is created. Null if not created or the create call failed.

getErrorListener

public MonitoredItemErrorListener getErrorListener()

Returns the current error listener.

getExpandedNodeId

public ExpandedNodeId getExpandedNodeId()

Returns:

the expandedNodeId

getInitialStatus

public StatusCode getInitialStatus()

The initial status tells if the creation of the MonitoredItem succeeded in the first createMonitoredItems. It is used in Subscription.isRecreateFailedItems() to define if the item should be retried - if it never succeeded, it probably doesn't make sense to try to recreate it, since the item is truly invalid. But if it has succeeded, the chances are that the item really is in the server, but not yet, after a server restart.

Returns:

the initial status or null, if the item has never been created, yet.

getNodeId

public NodeId getNodeId()

Overrides:

getNodeId in class MonitoredItemBase

Returns:

the node to monitor

getSubscription

public Subscription getSubscription()

hashCode

public int hashCode()

Overrides:

hashCode in class MonitoredItemBase

isModified

public boolean isModified()

Returns:

the modified state, which is true when there are modifications in the item that need to be applied to the server side item.

isMonitoringModeModified

public boolean isMonitoringModeModified()

Returns:

the monitoringModeModified

setErrorListener

public void setErrorListener(MonitoredItemErrorListener statusListener)

Sets a listener for observing when getErrorCode() changes. This is related to the item creation on the server.

clearModified

protected void clearModified()

clearMonitoringModeModified

protected void clearMonitoringModeModified()

fireError

protected void fireError(StatusCode newErrorCode)

Triggers MonitoredItemErrorListener.onError(MonitoredItem, StatusCode), if listener set to this item.

getNodeIdAsString

protected String getNodeIdAsString()

Overrides:

getNodeIdAsString in class MonitoredItemBase

itemChanged

protected void itemChanged()
                    throws ServiceException

Throws:

ServiceException

monitoringModeChanged

protected void monitoringModeChanged()
                              throws ServiceException

Overrides:

monitoringModeChanged in class MonitoredItemBase

Throws:

ServiceException

setClientHandle

protected void setClientHandle(int i)

Parameters:

i -

setErrorCode

protected void setErrorCode(StatusCode statusCode)

Parameters:

statusCode -

setFilterResult

protected void setFilterResult(MonitoringFilterResult filterResult)

Overrides:

setFilterResult in class MonitoredItemBase

Parameters:

filterResult -

setMonitoredItemId

protected void setMonitoredItemId(UnsignedInteger monitoredItemId)

Overrides:

setMonitoredItemId in class MonitoredItemBase

setRevisedQueueSize

protected void setRevisedQueueSize(UnsignedInteger revisedQueueSize)

Parameters:

revisedQueueSize -

updateFilter

protected void updateFilter()
                     throws ServiceException

Description copied from class: MonitoredItemBase

React to changes in the filter.

Overrides:

updateFilter in class MonitoredItemBase

Throws:

ServiceException

updateQueue

protected void updateQueue()
                    throws ServiceException

Description copied from class: MonitoredItemBase

Update the queue, when it's size has changed.

Overrides:

updateQueue in class MonitoredItemBase

Throws:

ServiceException