com.prosysopc.ua

Class MonitoredItemBase

java.lang.Object

com.prosysopc.ua.MonitoredItemBase

Direct Known Subclasses:

MonitoredItem, MonitoredItem

public abstract class MonitoredItemBase
extends Object

The base class for all OPCUA MonitoredItems. It defines the necessary properties for every item.

Field Summary

Fields

Modifier and Type	Field and Description
protected UnsignedInteger	attributeId
protected UnsignedInteger	clientHandle
protected QualifiedName	dataEncoding
protected boolean	discardOldest
protected static int	maxQueueSize
protected UnsignedInteger	monitoredItemId
protected MonitoringMode	monitoringMode
protected NodeId	nodeId
protected MonitoringMode	prevMonitoringMode
protected long	queueSize

Constructor Summary

Constructors

Constructor and Description
MonitoredItemBase(UnsignedInteger clientHandle, UnsignedInteger monitoredItemId, NodeId nodeId, UnsignedInteger attributeId, MonitoringMode monitoringMode) Create a new monitored item in a subscription.

Method Summary

Modifier and Type	Method and Description
void	close() Close down the monitoredItem, when it is removed from the subscription.
boolean	equals(Object obj)
UnsignedInteger	getAttributeId()
UnsignedInteger	getClientHandle() Client-supplied id of the MonitoredItem.
QualifiedName	getDataEncoding()
protected abstract long	getDefaultQueueSize()
MonitoringFilter	getFilter() A filter used by the Server to determine if the MonitoredItem should generate a Notification.
MonitoringFilterResult	getFilterResult()
NumericRange	getIndexRange() Optional subrange of an array to monitor to.
UnsignedInteger	getMonitoredItemId()
MonitoringMode	getMonitoringMode() See the setter for a full description.
NodeId	getNodeId()
protected String	getNodeIdAsString()
protected MonitoringMode	getPrevMonitoringMode() Returns the previous MonitoringMode that was active before current, returned by getMonitoringMode().
long	getQueueSize()
double	getSamplingInterval() The SamplingInterval.
Object	getUserData() Returns a previously setUserData(Object) object.
int	hashCode()
boolean	isDiscardOldest()
protected void	monitoringModeChanged()
void	setDiscardOldest(boolean discardOldest) A boolean parameter that specifies the discard policy when the queue is full and a new Notification is to be enqueued.
protected void	setFilter(MonitoringFilter filter) A filter used by the Server to determine if the MonitoredItem should generate a Notification.
protected void	setFilterResult(MonitoringFilterResult filterResult)
protected void	setMonitoredItemId(UnsignedInteger monitoredItemId)
void	setMonitoringMode(MonitoringMode monitoringMode) Set the monitoring mode.
void	setQueueSize(long queueSize) The requested size of the MonitoredItem queue.
void	setQueueSize(UnsignedInteger queueSize)
void	setUserData(Object userData) Set a custom data object to this item that can be later retrieved with getUserData().
String	toString()
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 java.lang.Object

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

Field Detail

maxQueueSize

protected static int maxQueueSize

attributeId

protected final UnsignedInteger attributeId

clientHandle

protected UnsignedInteger clientHandle

dataEncoding

protected final QualifiedName dataEncoding

discardOldest

protected boolean discardOldest

monitoredItemId

protected UnsignedInteger monitoredItemId

monitoringMode

protected volatile MonitoringMode monitoringMode

prevMonitoringMode

protected volatile MonitoringMode prevMonitoringMode

nodeId

protected final NodeId nodeId

queueSize

protected long queueSize

Constructor Detail

MonitoredItemBase

public MonitoredItemBase(UnsignedInteger clientHandle,
                         UnsignedInteger monitoredItemId,
                         NodeId nodeId,
                         UnsignedInteger attributeId,
                         MonitoringMode monitoringMode)

Create a new monitored item in a subscription.

Parameters:

clientHandle - a handle used to identify the item in the client side, assigned by the client

monitoredItemId - the ID used to identify the item in the server side, assigned by the server

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

close

public void close()

Close down the monitoredItem, when it is removed from the subscription.

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

getAttributeId

public UnsignedInteger getAttributeId()

Returns:

the attribute to monitor to.

getClientHandle

public UnsignedInteger getClientHandle()

Client-supplied id of the MonitoredItem. This id is used in Notifications generated for the list Node. The id is generated automatically by the client items.

Returns:

the handle of the monitored item

See Also:

getMonitoredItemId()

getDataEncoding

public QualifiedName getDataEncoding()

Returns:

the data encoding to use or null to use the default encoding

getFilter

public MonitoringFilter getFilter()

A filter used by the Server to determine if the MonitoredItem should generate a Notification.

Returns:

the current filter. If not used, this is null.

getFilterResult

public MonitoringFilterResult getFilterResult()

Returns:

getIndexRange

public NumericRange getIndexRange()

Optional subrange of an array to monitor to.

Returns:

the index range of an array to monitor.

getMonitoredItemId

public UnsignedInteger getMonitoredItemId()

Returns:

the ID of the monitored item. The ID is assigned by the server.

See Also:

getClientHandle()

getMonitoringMode

public MonitoringMode getMonitoringMode()

See the setter for a full description.

Returns:

current monitoring mode.

See Also:

setMonitoringMode(MonitoringMode)

getNodeId

public NodeId getNodeId()

Returns:

the node to monitor

getQueueSize

public long getQueueSize()

Returns:

the queue size. When the item is created in the server, this is the value revised by the server.

See Also:

setQueueSize(long)

getSamplingInterval

public double getSamplingInterval()

The SamplingInterval. This is only used for the monitored data items. For event items it is always 0.

Returns:

the requested sampling interval in milliseconds. If negative, then the publishingInterval of the Subscription is used.

getUserData

public Object getUserData()

Returns a previously setUserData(Object) object.

hashCode

public int hashCode()

Overrides:

hashCode in class Object

isDiscardOldest

public boolean isDiscardOldest()

Returns:

whether to discard the oldest or newest value, if the queue gets full in the server side.

See Also:

setDiscardOldest(boolean)

setDiscardOldest

public void setDiscardOldest(boolean discardOldest)

A boolean parameter that specifies the discard policy when the queue is full and a new Notification is to be enqueued. It has the following values:

true	the oldest (first) Notification in the queue is discarded. The new Notification is added to the end of the queue.
false	the new Notification is discarded. The queue is unchanged.

Default: false

Parameters:

discardOldest - the new value to set

setMonitoringMode

public void setMonitoringMode(MonitoringMode monitoringMode)
                       throws ServiceException

Set the monitoring mode.

The value of the publishing enabled parameter for a Subscription does not affect the value of the monitoring mode for a MonitoredItem of the Subscription

The values are

Value	Description>
Disabled	The item is not sampled nor reported.
Sampling	The item is sampled, but not reported.
Reporting	The item is sampled and reported.

Note: This method changes the mode of a single item. If you wish to change several items at once from the client side, use Subscription#setMonitoringMode(MonitoringMode, com.prosysopc.ua.client.MonitoredItem...) instead.

Parameters:

monitoringMode - the new monitoring mode to set.

Throws:

ServiceException - if the mode change fails

See Also:

getMonitoringMode(), SubscriptionBase.setPublishingEnabled(boolean)

setQueueSize

public void setQueueSize(long queueSize)
                  throws ServiceException

The requested size of the MonitoredItem queue. If Events are lost an Event of the type EventQueueOverflow is generated.

The following values have special meaning:

Value	Meaning
1	the queue has a single entry, effectively disabling queuing.
>1	a first-in-first-out queue is to be used.
Max Value (UnsignedInteger.MAX_VALUE.getValue())	the max size that the Server can support. This is used for Event Notifications. In this case the Server is responsible for the Event buffer.

If 0 is passed by the client, the server shall set the queue size to 1 and return 1 as revisedQueueSize.

Parameters:

queueSize - the value must be between 0 and UnsignedInteger.MAX_VALUE.getValue(). Value of 0 is changed to 1.

Throws:

ServiceException

setQueueSize

public void setQueueSize(UnsignedInteger queueSize)
                  throws ServiceException

Parameters:

queueSize -

Throws:

ServiceException

setUserData

public void setUserData(Object userData)

Set a custom data object to this item that can be later retrieved with getUserData(). This can be used to store business logic object mapping directly in the item. It will be stored using strong reference and equivalent to having the 'volatile' keyword. Set null to remove. This data is not used in equals(Object), hashCode() or toString().

toString

public String toString()

Overrides:

toString in class Object

getDefaultQueueSize

protected abstract long getDefaultQueueSize()

Returns:

getNodeIdAsString

protected String getNodeIdAsString()

getPrevMonitoringMode

protected MonitoringMode getPrevMonitoringMode()

Returns the previous MonitoringMode that was active before current, returned by getMonitoringMode(). Returns null if we are in the initial state after construction, which is Disabled. This data is mainly intended for SDK internals.

monitoringModeChanged

protected void monitoringModeChanged()
                              throws ServiceException

Throws:

ServiceException

setFilter

protected void setFilter(MonitoringFilter filter)
                  throws ServiceException

A filter used by the Server to determine if the MonitoredItem should generate a Notification. If not used, this parameter is null. The filter type depends on type of item being monitored. The main types are

DataChangeFilter	The change in a data value that will cause a Notification to be generated.
EventFilter	If a Notification conforms to the EventFilter, the Notification is sent to the Client.
AggregateFilter	The aggregate and its intervals when it will be calculated and a Notification is generated.

See the respective type definitions in org.opcfoundation.org.core.

Parameters:

filter -

Throws:

StatusException

ServiceException

setFilterResult

protected void setFilterResult(MonitoringFilterResult filterResult)

Parameters:

filterResult - the filterResult to set

setMonitoredItemId

protected void setMonitoredItemId(UnsignedInteger monitoredItemId)

updateFilter

protected void updateFilter()
                     throws ServiceException

React to changes in the filter.

Throws:

StatusException

ServiceException

updateQueue

protected void updateQueue()
                    throws ServiceException

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

Throws:

ServiceException