DataHub™ APIs for C++, Java, and .NET
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DataHub™ APIs for C++, Java, and .NET

Version 7.3

September 04, 2024

An open set of application programming interfaces used to connect custom programs to Cogent DataHub™ software, using DHTP.

Table of Contents
1. Introduction
1.1. Preliminaries
1.2. C++ Programming
1.3. Java Programming
1.4. .NET Programming
1.5. Example Programs
2. The DataHubConnector Class
2.1. Overview
2.2. Categorized List of Methods
2.3. Making Callbacks
3. The DataHubPoint Class
3.1. Overview
3.2. Categorized List of Methods
1. GNU General Public License
2. GNU Lesser General Public License
DataHubConnector Methods
DataHubConnector — creates a DataHubConnector object.
~DataHubConnector — destroys a DataHubConnector object.
activeHeartbeatTimers — determines if both heartbeat timers are active.
addPointValue — adds a specified amount to a DataHub point value.
appendPointValue — appends a string to a DataHub point.
cancelHeartbeatTimers — cancels the heartbeat and timeout timers.
cancelReconnectionTimer — stops the delay timer for reconnection attempts.
closeConnection — closes the connection to the DataHub instance.
createPoint — creates a DataHub point.
dividePointValue — divides the value of the named point by the specified value.
escapedString — prepares a string for use with writeCommand (Java and C# only).
getCnxState — retrieves the operational state of the connector object.
getCnxStateString — retrieves a string corresponding to the operational state.
getCnxSubStateString — provides detailed information on the connection state (C++ only).
getDefaultDomain — returns the current default domain.
getErrString — retrieves the last error string (C++ only).
getHeartbeat — retrieves the heartbeat timer period.
getHostName — retrieves the host name connection parameter.
getPort — retrieves the port connection parameter.
getReconnectionDelay — retrieves the delay time between reconnection attempts.
getServiceName — retrieves the port service name connection parameter (C++ only).
getTimeout — retrieves the timeout timer period.
initializePointCache — initializes local point cache usage.
isConnected — indicates whether a connection has been established.
isConnecting — indicates whether a connection attempt is in progress.
lookupPoint — accesses a point from the point cache.
multiplyPointValue — multiplies a DataHub point value by a specified amount.
openConnection — attempts to establish a connection to the DataHub instance.
readPoint — gets the value of a DataHub point.
registerDomain — registers to receive updates from domain points.
registerPoint — registers to receive updates from a DataHub point.
retryConnection — opens a new connection to the DataHub instance (C++ only).
sendBinaryPointMessages — formats data in binary mode (C++ only).
sendLispMessage — sends a message to the DataHub instance (C++ only).
sendLogin — transmits the user name and password.
setConnectionParms — sets the connection parameters.
setDefaultDomain — sets the default domain.
setHeartbeatTimes — sets the period of the heartbeat timers.
setPointLock — sets the lock attributes of a DataHub point.
setPointSecurity — sets the security attributes of a DataHub point.
setReconnectionDelay — sets the delay time between reconnection attempts.
setUsername — stores a user name and password for this connection.
shutdown — prepares for an application shutdown or disconnect (Java and C# only).
startHeartbeatTimers — starts the heartbeat and timeout timers.
startReconnectionTimer — starts the delay timer for reconnection attempts.
unregisterPoint — stops receiving updates from a DataHub point.
writeCommand — sends a command to the DataHub instance (Java and C# only).
writePoint — writes a new value to a DataHub point.
Callback Methods
onAlive — a virtual method invoked on receipt of a heartbeat from the DataHub instance.
onAsyncMessage — a virtual method invoked on receipt of a DataHub message.
onConnectionFailure — a virtual method invoked when a connection or attempt to connect fails.
onConnectionSuccess — a virtual method invoked when a connection is established.
onError — a virtual method invoked on receipt of an error message.
onPointChange — a virtual method invoked on receipt of a point value change.
onPointEcho — a virtual method invoked on receipt of a locally changed point value.
onStatusChange — a virtual method invoked on change of status.
onSuccess — a virtual method invoked on receipt of a success message.
DataHubPoint Methods
DataHubPoint — constructs a DataHubPoint object.
~DataHubPoint — destroys a DataHubPoint object.
operator= — assigns a new value to a DataHubPoint object (C++ only).
clear — clears the point.
copy — copies the point data.
getConfidence — retrieves the user's point confidence.
getDateString — generates a 'standard' timestamp data/time representation.
getDoubleValue — retrieves the point data as a double-typed value.
getFlags — retrieves the flags property of the point.
getIntValue — retrieves the point data as an int-typed value.
getListeners — retrieves listeners on the point (Java only).
getLocked — retrieves the locked property of the point.
getName — retrieves the point name.
getNanoseconds — retrieves the timestamp nanoseconds component.
getQuality — retrieves the point quality.
getQualityString — generates a string representing the point quality.
getSeconds — retrieves the timestamp seconds component.
getSecurity — retrieves the security property of the point.
getStringValue — retrieves the point data as a string.
getType — retrieves the point data type.
getUserdata — retrieves the user object associated with the point.
qualifyName — creates a point name string qualified by a domain name.
removeListener — removes a listener from the point (Java only).
setConfidence — sets the user's confidence in a point.
setInfo — sets the information properties of a point.
setLocked — sets the locked property of the point.
setName — assigns a name to the point.
setQuality — sets the point quality.
setSecurity — sets the security property of the point.
setTimeStamp — sets the point timestamp in various ways.
setFlags — sets the flags property of the point.
setUserdata — associates the point with a user object.
setValue — sets the point data to the specified type and value.
setValueFromString — sets the point data to the value represented by a string.
unqualifyName — removes the domain name qualifier from a point name.
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