com.prosysopc.ua.client

Class NodeCache

java.lang.Object

com.prosysopc.ua.NodeMap

com.prosysopc.ua.client.NodeCache

public class NodeCache
extends NodeMap

A client side cache of UaNode objects retrieved from the server.

See Also:

AddressSpace.getCache()

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	NodeCache.NodeCacheWrapper A wrapper which keeps track of time when a node was added to the cache.

Field Summary

Fields inherited from class com.prosysopc.ua.NodeMap

defaultLocale, nodeFactory

Constructor Summary

Constructors

Constructor and Description
NodeCache(UaNodeFactory nodeFactory, int maxQueueLength, long nodeMaxAgeInMillis) Creates new NodeCache.

Method Summary

Modifier and Type	Method and Description
UaNode	addNode(UaNode node)
protected UaNode	addNode(UaNode node, DateTime timestamp)
UaNode	addPermanently(UaNode node) Add a node permanently to the cache.
void	clear() Clear the node map of all entries.
protected UaNode	createNode(NodeClass nodeClass, NodeId nodeId, QualifiedName browseName, LocalizedText displayName, ExpandedNodeId typeDefinition) Create a new node and add it to the cache.
int	getMaxQueueLength() The maximum number of nodes to keep in the cache queue.
UaNode	getNode(NodeId nodeId)
long	getNodeMaxAgeInMillis() Maximum age of a node in the cache.
boolean	hasNode(NodeId nodeId) Check if the map contains a node with the specified NodeId.
protected boolean	isPermanentTimestamp(DateTime timestamp) Checks if a timestamp is considered as permanent for the purpose of storing the node.
UaNode	remove(NodeId nodeId) Remove a node from the node map.
UaNode	remove(UaNode node) Remove a node from the node map.
void	setMaxQueueLength(int maxQueueLength) Set the maximum queue length.
void	setNodeMaxAgeInMillis(long nodeMaxAgeInMillis) Set the maximum time to keep nodes in the cache.
int	size() Returns the current size of the cache.

Methods inherited from class com.prosysopc.ua.NodeMap

getNodeFactory

Methods inherited from class java.lang.Object

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

Constructor Detail

NodeCache

public NodeCache(UaNodeFactory nodeFactory,
                 int maxQueueLength,
                 long nodeMaxAgeInMillis)

Creates new NodeCache.

Parameters:

nodeFactory - factory used to create UaNode instances

maxQueueLength - max amount nodes to cache

nodeMaxAgeInMillis - maximum time a node is cached

Method Detail

addNode

public UaNode addNode(UaNode node)

Specified by:

addNode in class NodeMap

addPermanently

public UaNode addPermanently(UaNode node)

Add a node permanently to the cache. It is not included in the queue, which limits the size of the cache. If there was already a node with the same NodeId, the method returns that.

Parameters:

node - the node to add

Returns:

the previous node with the same NodeId in the cache - or null, if there was not such a node

clear

public void clear()

Description copied from class: NodeMap

Clear the node map of all entries.

Specified by:

clear in class NodeMap

getMaxQueueLength

public int getMaxQueueLength()

The maximum number of nodes to keep in the cache queue. When the queue gets full, oldest nodes are removed from the cache.

Returns:

the current max of the queue length

getNode

public UaNode getNode(NodeId nodeId)

Specified by:

getNode in class NodeMap

getNodeMaxAgeInMillis

public long getNodeMaxAgeInMillis()

Maximum age of a node in the cache. If a node gets older, i.e. it was added to the cache too long time ago, it will get removed from the cache and needs to be re-added.

Returns:

the maximum time to keep nodes in the cache, in milliseconds

hasNode

public boolean hasNode(NodeId nodeId)

Description copied from class: NodeMap

Check if the map contains a node with the specified NodeId.

Specified by:

hasNode in class NodeMap

Parameters:

nodeId - the ID to check

Returns:

true, if the map contains a node with ID

remove

public UaNode remove(NodeId nodeId)

Description copied from class: NodeMap

Remove a node from the node map.

Specified by:

remove in class NodeMap

Parameters:

nodeId - the node to remove.

Returns:

the node that was removed or null, if it was not in the map.

remove

public UaNode remove(UaNode node)

Description copied from class: NodeMap

Remove a node from the node map.

Overrides:

remove in class NodeMap

Parameters:

node - the node to remove.

Returns:

the node that was removed or null, if it was not in the map.

setMaxQueueLength

public void setMaxQueueLength(int maxQueueLength)

Set the maximum queue length.

Parameters:

maxQueueLength - the max length

See Also:

getMaxQueueLength()

setNodeMaxAgeInMillis

public void setNodeMaxAgeInMillis(long nodeMaxAgeInMillis)

Set the maximum time to keep nodes in the cache.

Parameters:

nodeMaxAgeInMillis - max time in milliseconds

See Also:

getNodeMaxAgeInMillis()

size

public int size()

Returns the current size of the cache.

addNode

protected UaNode addNode(UaNode node,
                         DateTime timestamp)

createNode

protected UaNode createNode(NodeClass nodeClass,
                            NodeId nodeId,
                            QualifiedName browseName,
                            LocalizedText displayName,
                            ExpandedNodeId typeDefinition)
                     throws UaNodeFactoryException

Create a new node and add it to the cache. The created type of the node depends on the parameters, namely nodeClass and typeDefinition. The call is by default delegated to the UaNodeFactory given in the constructor.

Throws:

UaNodeFactoryException

isPermanentTimestamp

protected boolean isPermanentTimestamp(DateTime timestamp)

Checks if a timestamp is considered as permanent for the purpose of storing the node. DateTime.MAX_VALUE are considered as permanent, i.e. the node is stored forever in the cache.