I am using an aggregating server. The code is largely based on the samples provided in the package. The package itself is old (2.02 – 275) but that probably does not matter in this case.

To relay variable subscriptions on the aggregating server to the original source servers, the NodeManagerListener needs a structure for finding the source server. This structure is the clientMap.

Creating the NodeManagerListener:

private static NodeManagerListener myNodeManagerListener = new ASNodeManagerListener();

In the NodeManagerListener, creating the clientMap:

private HashMap clientMap = new HashMap(100);

In the NodeManagerListener, creating a monitored data item:

@Override
public void onCreateMonitoredDataItem(ServiceContext serviceContext,
Subscription subscription, UaNode node,
UnsignedInteger attributeId, NumericRange indexRange,
MonitoringParameters params, MonitoringFilter filter,
AggregateFilterResult filterResult) throws StatusException {
// Notification of a monitored item creation request
int ns = node.getNodeId().getNamespaceIndex();

// THIS SHOWS IF THE CLIENTMAP IS EMPTY OR NOT
System.out.println(clientMap.toString());

TargetServer ts = clientMap.get(ns);

System.out.println(“### onCreateMonitoredDataItem called for node ” + node + ” ###”);

if (ts != null) {
NodeId remoteId = ts.getNodeManager().getIdMap().get(node.getNodeId());
if (remoteId != null) {
ts.client.relaySubscription(remoteId, attributeId);
ts.client.storeMonitoredIdPair(remoteId, node.getNodeId());
if (node.supportsAttribute(Attributes.AccessLevel)) {
nodeAccessLevels.put(node, ((UaVariable)node).getAccessLevel());
((UaVariable) node).setAccessLevel(AccessLevel.READWRITE);
}
}
} else
System.out.println(” The TargetServer was null!”);
}

public void updateIdMap(TargetServer ts) {
System.out.println(” clientMap is updated!”);
int ns = ts.getNodeManager().getNamespaceIndex();
if (clientMap.get(ns) == null) {
clientMap.put(ns, ts);
}
System.out.println(clientMap.toString());
}

The updateIdMap method is supposed to update the clientMap, and the Print at the end shows that the clientMap is at least seemingly updated. However, when testing with a console client and in UA Expert, the clientMap is actually always empty.
I realize this might be more about Java itself than the SDK, but I haven’t been able to find a solution yet. Could the problem have something to do with the static keyword?