/// <summary>
/// Assigns the handles to the requests.
/// </summary>
/// <param name="client">The client.</param>
/// <param name="requests">The requests.</param>
private void AssignHandles(ComHdaClient client, Dictionary <string, HdaSubscribeAttributeRequest> requests)
{
List <string> itemIds = null;
lock (m_lock)
{
foreach (KeyValuePair <string, HdaSubscribeAttributeRequest> entry in requests)
{
if (entry.Value.ServerHandle == null)
{
if (itemIds == null)
{
itemIds = new List <string>();
}
itemIds.Add(entry.Key);
}
}
}
if (itemIds == null)
{
return;
}
HdaItem[] items = client.GetItems(itemIds.ToArray());
lock (m_lock)
{
for (int ii = 0; ii < items.Length; ii++)
{
HdaSubscribeAttributeRequest request = null;
if (!requests.TryGetValue(itemIds[ii], out request))
{
continue;
}
if (items[ii].Error < 0)
{
request.ServerHandle = null;
continue;
}
request.ServerHandle = items[ii].ServerHandle;
}
}
}
/// <summary>
/// Finds the item attributes request for the specifed item.
/// </summary>
/// <param name="itemId">The item id.</param>
/// <param name="create">if set to <c>true</c> a new request is created if it does not exist.</param>
/// <returns>The subscribe attribute request.</returns>
private HdaSubscribeAttributeRequest FindAttributeRequest(string itemId, bool create)
{
lock (m_lock)
{
HdaSubscribeAttributeRequest requests = null;
if (!m_requests.TryGetValue(itemId, out requests))
{
if (!create)
{
return(null);
}
requests = new HdaSubscribeAttributeRequest(itemId);
m_requests.Add(itemId, requests);
}
return(requests);
}
}
/// <summary>
/// Deletes subscription requests for monitored items.
/// </summary>
/// <param name="context">The context.</param>
/// <param name="monitoredItems">The monitored items.</param>
public void DeleteItems(ServerSystemContext context, IList <IMonitoredItem> monitoredItems)
{
lock (m_lock)
{
if (monitoredItems != null)
{
Dictionary <string, HdaSubscribeAttributeRequest> requests = new Dictionary <string, HdaSubscribeAttributeRequest>();
for (int ii = 0; ii < monitoredItems.Count; ii++)
{
MonitoredItem monitoredItem = monitoredItems[ii] as MonitoredItem;
if (monitoredItem == null)
{
continue;
}
NodeHandle handle = monitoredItem.ManagerHandle as NodeHandle;
if (handle == null)
{
continue;
}
if (!HasExternalSource(handle.Node, monitoredItem.AttributeId))
{
continue;
}
HdaSubscribeAttributeRequest request = Remove(handle.Node, monitoredItem);
if (request != null)
{
requests[request.ItemId] = request;
}
}
ApplyChanges(requests, false);
}
}
}
/// <summary>
/// Modifies the monitored item to the collection.
/// </summary>
/// <param name="source">The source.</param>
/// <param name="monitoredItem">The monitored item.</param>
private HdaSubscribeAttributeRequest Modify(NodeState source, MonitoredItem monitoredItem)
{
lock (m_lock)
{
// get the HDA item id.
string itemId = GetItemId(source);
// update the subscribe request for the HDA item.
if (itemId != null)
{
HdaSubscribeAttributeRequest request = FindAttributeRequest(itemId, false);
if (request != null)
{
request.Modify(m_context, monitoredItem);
return(request);
}
}
return(null);
}
}
/// <summary>
/// Adds the monitored item to the collection.
/// </summary>
/// <param name="source">The source.</param>
/// <param name="monitoredItem">The monitored item.</param>
private HdaSubscribeAttributeRequest Add(NodeState source, MonitoredItem monitoredItem)
{
lock (m_lock)
{
m_monitoredItems.Add(monitoredItem.Id, monitoredItem);
// get the HDA item id.
string itemId = GetItemId(source);
// create/update the subscribe request for the HDA item.
if (itemId != null)
{
HdaSubscribeAttributeRequest request = FindAttributeRequest(itemId, true);
if (request != null)
{
request.Add(m_context, monitoredItem);
return(request);
}
}
return(null);
}
}
/// <summary>
/// Applies any changes to the subscriptions.
/// </summary>
private void ApplyChanges(Dictionary <string, HdaSubscribeAttributeRequest> requests, bool initialUpdateRequired)
{
List <HdaSubscribeAttributeRequest> requestsToRemove = null;
lock (m_lock)
{
// update existing requests.
foreach (KeyValuePair <string, HdaSubscribeAttributeRequest> entry in requests)
{
HdaSubscribeAttributeRequest request = entry.Value;
// remove unused requests.
if (request.MonitoredItems == null || request.MonitoredItems.Count == 0)
{
if (requestsToRemove == null)
{
requestsToRemove = new List <HdaSubscribeAttributeRequest>();
}
requestsToRemove.Add(entry.Value);
continue;
}
request.ChangesComplete(m_configuration.AttributeSamplingInterval);
}
// remove deleted requests from dictionary.
if (requestsToRemove != null)
{
for (int ii = 0; ii < requestsToRemove.Count; ii++)
{
m_requests.Remove(requestsToRemove[ii].ItemId);
}
}
// check if the attribute scanner needs to be stopped/started.
if (m_attributeScanTimer == null)
{
if (m_requests.Count > 0)
{
m_attributeScanTimer = new Timer(OnScanAttributes, null, m_configuration.AttributeSamplingInterval, m_configuration.AttributeSamplingInterval);
}
}
else
{
if (m_requests.Count == 0)
{
m_attributeScanTimer.Dispose();
m_attributeScanTimer = null;
}
}
}
// release any unused handles.
if (requestsToRemove != null)
{
ComHdaClientManager system = (ComHdaClientManager)m_context.SystemHandle;
ComHdaClient client = (ComHdaClient)system.SelectClient(m_context, false);
ReleaseHandles(client, requestsToRemove);
}
// send initial update.
if (initialUpdateRequired)
{
DoScan(requests, true);
}
}
/// <summary>
/// Finds the item attributes request for the specifed item.
/// </summary>
/// <param name="itemId">The item id.</param>
/// <param name="create">if set to <c>true</c> a new request is created if it does not exist.</param>
/// <returns>The subscribe attribute request.</returns>
private HdaSubscribeAttributeRequest FindAttributeRequest(string itemId, bool create)
{
lock (m_lock)
{
HdaSubscribeAttributeRequest requests = null;
if (!m_requests.TryGetValue(itemId, out requests))
{
if (!create)
{
return null;
}
requests = new HdaSubscribeAttributeRequest(itemId);
m_requests.Add(itemId, requests);
}
return requests;
}
}
