File Information
Library: IoT/Devices
Package: Datapoints
Header: IoT/Devices/Datapoint.h
Description
The base class for datapoints. Datapoints typically represent the result of sensor measurements, or data obtained from monitoring processes.
The main difference between a Datapoint and a Sensor is that a Sensor is typically an interface to a specific device (i.e., a temperature sensor), whereas a Datapoint holds a value that has been acquired from another device (via a network or bus system) or computed from other data points.
In addition to the methods defined in this interface, a Sensor implementation should expose the following properties:
- displayValue (string, optional): The current value of the datapoint, formatted as string for display purposes.
- updated (timestamp, optional): The point in time when the datapoint's value was last updated.
- access (string, optional): Access permissions ("rw" - read/write, "ro" - read-only, "wo" - write-only).
Subclasses of Datapoint implement specific value types.
Inheritance
Direct Base Classes: Device
All Base Classes: Device
Known Derived Classes: StringDatapoint, BooleanDatapoint, VectorDatapoint, CounterDatapoint, FlagsDatapoint, ScalarDatapoint, EnumDatapoint
Member Summary
Member Functions: invalidate, valid
Inherited Functions: getFeature, getPropertyBool, getPropertyDouble, getPropertyInt, getPropertyInt16, getPropertyInt64, getPropertyString, getPropertyTimestamp, hasFeature, hasProperty, setFeature, setPropertyBool, setPropertyDouble, setPropertyInt, setPropertyInt16, setPropertyInt64, setPropertyString, setPropertyTimestamp
Constructors
Datapoint
Datapoint();
Creates the Datapoint.
Destructor
~Datapoint 
~Datapoint();
Destroys the Datapoint.
Member Functions
invalidate
virtual void invalidate() = 0;
Invalidates the datapoint's value.
Subsequent calls to valid() will return false, until a new value has been set.
valid
virtual bool valid() const = 0;
Returns true if a valid value is available.
Note that between the time valid() is called and a subsequent call to value() or similar method, the validity may change. Use validValue() or similar methods of subclasses to atomically get validity and value.
Variables
invalidated
Poco::BasicEvent < void > invalidated;
Fired when the datapoint has been invalidated.