SpecTcl Programming Guide.
PrevNext

Chapter 12. Dynamic processing pipelines

Beginning with SpecTcl 5.1, SpecTcl supports dynamic event processsing pipelines. At the very least, this allows you to use the same SpecTcl executable image to analyze raw data and to playback filter files. You can also use it to selectively enable analysis or to allow a single SpecTcl executable to analyze data from a wide variety of data formats.

To use this facility you must:

In this chapter we'll give sample code that shows how to create instances of event processors and how to register them with the pipeline manager singleton. We'll also give examples of Tcl command sequences that build up and select event processing pipelines.

Before continuing, let me reassure you that all of your existing SpecTcl code should work just fine. When SpecTcl starts, it creates a pipeline named default and sets that pipeline as the current event processing pipeline. The CreateAnalysisPipeline code you use registers event processors you create (they must be uniquely named or have default names) and adds them to the current event processing pipeline. Thus everything we describe in this chapter is optional.

12.1. Creating and registering event processors.

To use dynamic event processors, you must have a set of event processor instances, each registered with the pipeline manager singleton under a unqique name. In this section, I'll show how to create a few event processors and register them with the pipeline manager. This code could appear in CreateAnalysisPipeline. We're going to assume you have created event processor classes namec Evp1, Evp2 and Evp3. Additionally, we're going to instantiate and register the filter event processor that comes with SpecTcl.

Example 12-1. Creating and registering


#include <FilterEventProcessor.h>
#include "Evp1.h"
#include "Evp2.h"                           (1)
#include "Evp3.h"
#include <CPipelineManager.h>
....
void
CMySpecTclApp::CreateAnalysisPipeline(CAnalyzer& rAnalyzer)
{
    CPipelineManager* pMgr = CPipelineManager::getInstance()  (2)
    
    pMgr->registerEventProcessor("evp1", new Evp1);
    pMgr->registerEventProcessor("evp2", new Evp2);           (3)
    pMgr->registerEventProcessor("evp3", new Evp3);
    pMgr->registerEventProcessor("filter", new CFilterEventProcessor);
}
(1)
These includes, presumably pull in the class definitions for the your Evp1 .. Evp3 classes, the CFilterEventProcessor definition and definition of CPipelineManager, the pipeline manager singleton.
(2)
Since the CPipelineManager is a singleton, you can't construct it. It's getInstance method (it's declared as private). returns a pointer to the one and only instance of this class.
(3)
Each of these calls registers an event processor with the pipeline manager. The first paramteer is a name that will be associated with the event processor instance. The second, a pointer to an instance of the event processor. If you attempt to register a duplicate name a std::logic_error exception will be thrown by the pipleline manager.

Note that we have not created any event processing pipelines. In this set of examples, we're going to do that at the Tcl script level. If you prefer, the pipeline manager does provide methods to create pipelines, add event processors to them to select the pipeline that SpecTcl will use to analyze data.

See the programming reference for a complete description of the methods provided by the pipeline manager singleton.

PrevHomeNext
Distributing the SomeDaqBufferDecoder as a plugin Using the pman command to create and select pipelines