ProjectionApplier.hh

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// -*- C++ -*-
#ifndef RIVET_ProjectionApplier_HH
#define RIVET_ProjectionApplier_HH

#include "Rivet/Config/RivetCommon.hh"
#include "Rivet/Projection.fhh"
#include "Rivet/ProjectionHandler.hh"
#include "Rivet/Tools/Logging.hh"

namespace Rivet {


  // Forward declarations
  class Event;


  /// @brief Common base class for Projection and Analysis, used for internal polymorphism
  ///
  /// Empty interface used for storing Projection and Analysis pointers in the
  /// same container (used by the ProjectionHandler)
  class ProjectionApplier {
  public:

    // The proj handler needs access to reset the _allowProjReg flag before calling a.init()
    // friend class ProjectionHandler;

    /// Constructor
    ProjectionApplier();

    // Virtual destructor: ensure that inheritance is possible.
    virtual ~ProjectionApplier();


  public:

    /// @name Metadata functions
    //@{
    /// Get the name of this Projection or Analysis class
    virtual std::string name() const = 0;
    //@}

    /// @name Projection "getting" functions
    //@{
    /// Get the contained projections, including recursion.
    std::set<ConstProjectionPtr> getProjections() const {
      return getProjHandler().getChildProjections(*this, ProjectionHandler::DEEP);
    }


    /// Get the named projection, specifying return type via a template argument.
    template <typename PROJ>
    const PROJ& getProjection(const std::string& name) const {
      const Projection& p = getProjHandler().getProjection(*this, name);
      return pcast<PROJ>(p);
    }


    /// Get the named projection (non-templated, so returns as a reference to a
    /// Projection base class).
    const Projection& getProjection(const std::string& name) const {
      return getProjHandler().getProjection(*this, name);
    }
    //@}


    /// @name Projection applying functions
    //@{
    /// Apply the supplied projection on @a event.
    template <typename PROJ>
    const PROJ& applyProjection(const Event& evt, const PROJ& proj) const {
      return pcast<PROJ>(_applyProjection(evt, proj));
    }


    /// Apply the supplied projection on @a event.
    template <typename PROJ>
    const PROJ& applyProjection(const Event& evt, const Projection& proj) const {
      return pcast<PROJ>(_applyProjection(evt, proj));
    }


    /// Apply the named projection on @a event.
    template <typename PROJ>
    const PROJ& applyProjection(const Event& evt, const std::string& name) const {
      return pcast<PROJ>(_applyProjection(evt, name));
    }
    //@}


  protected:

    Log& getLog() const {
      return Log::getLog("Rivet.ProjectionHandler");
    }

    /// Get a reference to the ProjectionHandler for this thread.
    ProjectionHandler& getProjHandler() const {
      return _projhandler;
    }


  protected:


    /// @name Projection registration functions
    //@{

    /// Register a contained projection. The type of the argument is used to
    /// instantiate a new projection internally: this new object is applied to
    /// events rather than the argument object. Hence you are advised to only use
    /// locally-scoped Projection objects in your Projection and Analysis
    /// constructors, and to avoid polymorphism (e.g. handling @c ConcreteProjection
    /// via a pointer or reference to type @c Projection) since this will screw
    /// up the internal type management.
    template <typename PROJ>
    const PROJ& addProjection(const PROJ& proj, const std::string& name) {
      const Projection& reg = _addProjection(proj, name);
      const PROJ& rtn = dynamic_cast<const PROJ&>(reg);
      return rtn;
    }


    /// Untemplated function to do the work...
    const Projection& _addProjection(const Projection& proj, const std::string& name);

    //@}


  private:

    /// Non-templated version of string-based applyProjection, to work around
    /// header dependency issue.
    const Projection& _applyProjection(const Event& evt, const std::string& name) const;

    /// Non-templated version of proj-based applyProjection, to work around
    /// header dependency issue.
    const Projection& _applyProjection(const Event& evt, const Projection& proj) const;


  protected:

    /// Flag to forbid projection registration in analyses until the init phase
    bool _allowProjReg;


  private:

    /// Pointer to projection handler.
    ProjectionHandler& _projhandler;

  };

}

#endif