org.lsst.ccs.subsystem.airwatch.main

Interface Instrument

All Known Implementing Classes:

DummyInstrument, LighthouseModbus, LighthouseOPC

public interface Instrument

Represents a particle-counting instrument. For ease of sharing between threads, objects implementing this interface must be immutable. In place of mutators there are methods that produce new instances with altered states.

When first constructed from subsystem configuration data each Instrument should be disabled, have no data and no stored exception.

Author:

tether

Method Summary

Modifier and Type	Method and Description
Instrument	disable() Produces a new instance that has readout disabled.
Instrument	enable(LocationConfig loc) Produces a new instance that has been enabled for readout and is serving a new location.
int	getIndex() Gets the position of this instrument in the list of instruments.
Optional<org.lsst.ccs.HardwareException>	getLastException() Gets the exception thrown (if any) the last time we tried to operate on this instrument.
InstrumentStatus	getStatus() Gets the current status of the instrument.
Stream<TrendableRecord>	getTrendables() Gets all the trendable data resulting from the last reading of the instrument.
Instrument	read() Produces a new instance that contains a fresh set of data read from the instrument.

Method Detail

getLastException

Optional<org.lsst.ccs.HardwareException> getLastException()

Gets the exception thrown (if any) the last time we tried to operate on this instrument.

Returns:

An empty Optional if there have been no operations or if the last operation was successful. Otherwise an Optional containing the exception that terminated the operation. Getters are not considered operations.

getIndex

int getIndex()

Gets the position of this instrument in the list of instruments.

Returns:

The index.

See Also:

LocalConfigService.getInstrumentConfigs()

getTrendables

Stream<TrendableRecord> getTrendables()

Gets all the trendable data resulting from the last reading of the instrument.

Returns:

A stream of TrendableRecord instances, empty if no data is available, for example if the instrument has never been read or if the last read found no new data or failed. The master key of each record is the location for which the data were taken. The master timestamp is the time at which the record was made. Each key/value pair consists of a channel name and value.

See Also:

read()

getStatus

InstrumentStatus getStatus()

Gets the current status of the instrument. This method will be used in QUERY-type commands, so implementations must rely solely on data in memory and must not perform any hardware operations.

Returns:

The status object.

disable

Instrument disable()

Produces a new instance that has readout disabled.

Returns:

The new instance.

enable

Instrument enable(LocationConfig loc)

Produces a new instance that has been enabled for readout and is serving a new location. The device will be reconfigured for the new location. For example, alarm thresholds will be altered.

Parameters:

loc - The configuration of the new location.

Returns:

The new instance.

read

Instrument read()

Produces a new instance that contains a fresh set of data read from the instrument. The getTrendables() method relies on this data to produce its result.

Returns:

The new instance.