The database can hold event and scaler data associated with a run. These data are placed in a saveset. SpecTcl records at most one run per saveset and includes in that save set, the analysis conditions in effect at the time the run was analyzed.
This also allows data from a run to be recorded more than once, using differing analysis configurations.
This section describes the classes used by SpecTcl to record event data. Note that in most cases, you don't need to use these classes. They are instantiated by the SpecTcl database GUI and automatically placed in the analysis and data sink piplines as requested.
These classes are organized into two layers. The lowest layer provides an interface between runs and the database API. The upper layer provides an interface between SpecTcl's flow of control and the lower layer.
The lower layer's header is CDBEvents.h. The upper layer's header is Events.h.
The lower layer of SpecTcl's event recording
and playback system consists of a pair of classes.
CDBEventWriter, as the
name implies, is used to record unpacked parameters and
scalers to the database.
CDBEventPlayer, as its name
implies is used to read event data back from the
database for a run in a save set.
CDBEventPlayer only reads
event data. It does not read scaler data. The
Tcl SpecTcl interface, however, has a mechanism
to test for the existence of scaler data and recover
it for a run in a saveset.
CDBEventWriter
the following methods of interest:
void beginRun(const RingItem* pStateTransition = );
This method must be the first one called to start recording a run. It provides a ring item, which must be a BEGIN_RUN item. It records information about the run and the start time of the run using data in the ring item.
This method handles multiple begin runs (as happens in event built data) by only saving information from the first call.
void endRun(const RingItem* pStateTransition = );
This method should be called when
end of run rinng items are available.
Note that the code is able to detect
multiple ends per run (as will be the
case in event built data) and, as with
the beginRun
call only saves information from the first one.
void scaler(const RingItem* pScaler = );
The pScaler parameter
must be a PERIODIC_SCALER ring item.
I is added to the scaler readouts for the run.
void event(CEvent* pEvent = );
Adds an event to the database. Note that events are added in bunches for the sake of efficiency. The bunch size is set at construction time and has a default value that's believed to be reasonable.
The pEvent is a pointer
to the object that contains unpacked data from
SpecTcl.
void setAutoSaveSpectra(const std::vector<std::string>& spectra = );
The SpecTcl code that manages saving events to the database provides the capability for automatically saving the contents of a set of spectra at the end of the run. THese spectra are referred to as autosaved spectra.
This method sets the names of the spectra that will be
autosaved from spectra.
Any spectra previously deisgnated as autosaved
are no longer autosaved (unless they are in the
spectra parameter).
void addAutoSaveSpectrum(const char* name = );
Adds the spectrum named by name
to the list of autosaved spectra. Existing autosaved
spectra are not removed from the list.
void removeAutoSaveSpectrum(const char* name = );
If the spectrum named name
is in the auto saved list, it is removed from
that list. All other spectra in that list
are not affected.
std::vector<RunInfo> listRuns();
Returns information about all runs saved in the database. The run information includes the name of the saveset it was recorded in.
CDBEventPlayer* playRun(int run = );
Locates the first saveset that has the
requested run recorded in it
and creates a playback object for that
run.
See the description of CDBEventPlayer.
To play back data the low level code supplies
a CDBEventPlayer. This
is constructed on a saveset and the run number
of a save set that's known to be stored in
that saveset.
The following methods are then available:
const SpecTclDB::SaveSet::Event& next();
Returns a reference to the next event in the run. This will be an empty event if you attempt to read past the last event. Note that the writer class does not write empty events to the database.
const std::string getTitle();
Returns the run's title string.