Package ch.psi.wica.model.app

Enum Class WicaDataAcquisitionMode

java.lang.Object
java.lang.Enum<WicaDataAcquisitionMode>
ch.psi.wica.model.app.WicaDataAcquisitionMode
All Implemented Interfaces:
Serializable, Comparable<WicaDataAcquisitionMode>, Constable
public enum WicaDataAcquisitionMode extends Enum<WicaDataAcquisitionMode>
Represents the data acquisition mode for a channel. This can be a channel that monitors the underlying control system variables, that polls them at a predefined rate or which polls the last cached value received when monitoring.

  • Enum Constant Details

    • POLL

      public static final WicaDataAcquisitionMode POLL
      Periodically sends a network request to the underlying control system asking it to provide updated information on the dynamically-changing properties of the control point. The information that is obtained is configurable but will usually include the current value of the control point. Additionally it is possible to request the control point's timestamp and alarm state.

      The received information is internally buffered by the Wica Server and sent out in batches as individual Server-Sent-Event (SSE) messages within the overall Wica Stream. The size of the polled-value buffer is configurable on the server by the system administrator. The rate at which the polled values are sent out in batches is configurable by the user as a property of each stream.

      Unlike values obtained by monitoring, values obtained by polling are NOT filterable. That's to say each polled value will be directly represented in the Wica Stream's SSE update messages.

      This mode allows the user to acquire information with the required update latency by configuration of the appropriate polling interval (but with consequential increase in the network demand).

      See Also:

    • MONITOR

      public static final WicaDataAcquisitionMode MONITOR
      Sends a single network request to the underlying control system asking it to provide notification of interesting changes to the dynamically-changing information associated with the control point.

      Interesting changes will usually include changes to the control point's current value (possibly outside certain defined limits) and additionally changes to the control point's alarm state.

      Notified values are internally buffered on the Wica Server, optionally FILTERED (if an appropriate rule has been defined), and published in batches as individual Server-Sent-Event (SSE) messages on the Wica Stream.

      The size of the internal monitored-value buffer is configured on the server by the system administrator. The rate at which the monitored values are sent out in batches is configurable by the user as a property of the stream.

      This mode is economical with network usage whilst optimising the latency with which updated information is posted to the Wica Stream.

      See Also:

    • POLL_AND_MONITOR

      public static final WicaDataAcquisitionMode POLL_AND_MONITOR
      Samples the dynamically-changing properties of the control point using a combination of POLL and MONITOR modes. By selection of an appropriate polling interval this mode can guarantee that the Wica Stream publishes a new value at least as often as every X milliseconds, seconds, minutes etc.

      This mode can be useful for updating a graphical plot of control point values at a periodic rate even when the value is not changing in the control system (that's to say when no monitor notifications are being posted). Another use case is to periodically verify that the control system monitoring is still working as expected (that's to say that the monitors on the control-points-of-interest have not quietly died).

      See Also:

    • POLL_MONITOR

      public static final WicaDataAcquisitionMode POLL_MONITOR
      Sends a single network request to the underlying control system asking it to provide notification of interesting changes to the dynamically-changing information associated with the control point. Internally buffers the most recently received notification information but does NOT publish this directly on the Wica Stream. Periodically samples the value that is buffered on the server, and publishes it as part of the Wica Stream's polled value flux.

  • Method Details

    • values

      public static WicaDataAcquisitionMode[] values()
      Returns an array containing the constants of this enum class, in the order they are declared.
      Returns:
      an array containing the constants of this enum class, in the order they are declared

    • valueOf

      public static WicaDataAcquisitionMode valueOf(String name)
      Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)
      Parameters:
      name - the name of the enum constant to be returned.
      Returns:
      the enum constant with the specified name
      Throws:
      IllegalArgumentException - if this enum class has no constant with the specified name
      NullPointerException - if the argument is null

    • doesPolling

      public boolean doesPolling()

    • doesMonitorPublication

      public boolean doesMonitorPublication()

    • doesMonitoring

      public boolean doesMonitoring()

    • doesMonitorPolling

      public boolean doesMonitorPolling()

    • doesNetworkPolling

      public boolean doesNetworkPolling()

    • toString

      public String toString()
      Overrides:
      toString in class Enum<WicaDataAcquisitionMode>