WriterProxy.h

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#ifndef CondTools_L1Trigger_WriterProxy_h
#define CondTools_L1Trigger_WriterProxy_h

#include "FWCore/Framework/interface/EventSetup.h"
#include "FWCore/Framework/interface/ESHandle.h"

#include "FWCore/PluginManager/interface/PluginFactory.h"

#include "FWCore/ServiceRegistry/interface/Service.h"
#include "CondCore/DBOutputService/interface/PoolDBOutputService.h"
#include "CondCore/DBCommon/interface/DbSession.h"
#include "CondCore/DBCommon/interface/DbScopedTransaction.h"

#include "CondTools/L1Trigger/interface/Exception.h"

#include <string>

namespace l1t
{

/* This is class that is used to save data to DB. Saving requires that we should know types at compile time.
 * This means that I cannot create simple class that saves all records. So, I create a base class, and template
 * version of it, that will procede with saving. This approach is the same as used in DataProxy.
 */
class WriterProxy
{
    public:
        virtual ~WriterProxy() {}

        /* Saves record and type from given event setup to pool DB. This method should not worry
         * about such things as IOV and so on. It should return new payload token and then
         * the framework would take care of it.
         *
         * This method should not care of pool transactions and connections management.
         * In case some need other methods, like delete and update, one should add more abstract
         * methods here.
         */

        virtual std::string save (const edm::EventSetup & setup) const = 0;

    protected:
};

/* Concrete implementation of WriteProxy. This will do all the saving, also user of new types that should be saved
 * should instaciate a new version of this class and register it in plugin system.
 */
template<class Record, class Type>
class WriterProxyT : public WriterProxy
{
    public:
        virtual ~WriterProxyT() {}

        /* This method requires that Record and Type supports copy constructor */
        virtual std::string save (const edm::EventSetup & setup) const
        {
            // load record and type from EventSetup and save them in db
            edm::ESHandle<Type> handle;

        try
          {
        setup.get<Record> ().get (handle);
          }
        catch( l1t::DataAlreadyPresentException& ex )
          {
        return std::string() ;
          }

        // If handle is invalid, then data is already in DB
       
        edm::Service<cond::service::PoolDBOutputService> poolDb;
        if (!poolDb.isAvailable())
          {
        throw cond::Exception( "DataWriter: PoolDBOutputService not available."
                       ) ;
          }
        cond::DbSession session = poolDb->session();
        cond::DbScopedTransaction tr(session);
        // if throw transaction will unroll
        tr.start(false);

        boost::shared_ptr<Type> pointer(new Type (*(handle.product ())));
        std::string payloadToken =  session.storeObject( pointer.get(),
                                 cond::classNameForTypeId(typeid(Type))
                                 );
        tr.commit();
        return payloadToken ;
        }
};

typedef edmplugin::PluginFactory<l1t::WriterProxy * ()> WriterFactory;

// Defines new type, creates static instance of this class and register it for plugin
#define REGISTER_L1_WRITER(record,type) \
    template class l1t::WriterProxyT<record, type>; \
    typedef l1t::WriterProxyT<record, type> record ## _ ## type ## _Writer; \
    DEFINE_EDM_PLUGIN(l1t::WriterFactory, record ## _ ## type ## _Writer, #record "@" #type "@Writer")

} // ns

#endif