    // @(#)root/meta:$Name:  $:$Id: TToggle.cxx,v 1.6 2005/06/21 17:09:26 brun Exp $
    // Author: Piotr Golonka   30/07/97

    /*************************************************************************
     * Copyright (C) 1995-2000, Rene Brun and Fons Rademakers.               *
     * All rights reserved.                                                  *
     *                                                                       *
     * For the licensing terms see $ROOTSYS/LICENSE.                         *
     * For the list of contributors see $ROOTSYS/README/CREDITS.             *
     *************************************************************************/

    //////////////////////////////////////////////////////////////////////////
    //                                                                      //
    // TToggle                                                              //
    //                                                                      //
    // This class defines toggling facility for both - object's method or   //
    // variables.                                                           //
    // Assume that user provides an object with a two-state field , and     //
    // methods to Get/Set value of this field. This object enables to switch//
    // values via this method when the only thing you know about the field  //
    // is the name of the method (or method itself) which sets the field.   //
    // This facility is required in context Pop-Up menu, when the only      //
    // information about how to toggle a field is a name of methhod which   //
    // sets it.                                                             //
    // This class may be also used for toggling an integer variable,        //
    // which may be important while building universal objects...           //
    // When user provides a "set-method" of name SetXXX this object tries   //
    // automaticaly find a matching "get-method" by lookin for a method     //
    // with name GetXXX, IsXXX or HasXXX for given object.                  //
    //                                                                      //
    //////////////////////////////////////////////////////////////////////////

    #include "TClass.h"
    #include "TMethod.h"
    #include "TToggle.h"
    #include "TDataMember.h"

    ClassImp(TToggle)

    //______________________________________________________________________________
     TToggle::TToggle()
    {
       // TToggle default constructor. You have to initialize it before using
       // by making a call to SetToggledVariable() or SetToggledObject().

       fState       =  kFALSE;
       fValue       = -1;
       fOnValue     =  1;
       fOffValue    =  0;
       fInitialized =  0;
       fObject      =  0;
       fGetter      =  0;
       fSetter      =  0;
       fTglVariable =  0;
    }

    //______________________________________________________________________________
     void TToggle::SetToggledVariable(Int_t &var)
    {
       // Initializes object for use with a variable - you pass it via reference
       // so it will be modified by Toggle.

       fTglVariable=&var;
       fValue=var;
    }

    //______________________________________________________________________________
     Bool_t TToggle::GetState()
    {
       // Returns the state of Toggle according to its current value and
       // fOnValue, returns true if they match.

       if (fInitialized)
          if (fGetter) fGetter->Execute(fObject, fValue);
       return (fState = (fValue == fOnValue));
    }

    //______________________________________________________________________________
     void TToggle::SetState(Bool_t state)
    {
       // Sets the value of toggle to fOnValue or fOffValue according to passed
       // argument.

       if (fInitialized) {
          char stringon[7];
          char stringoff[7];
          sprintf(stringon,"%li",fOnValue);
          sprintf(stringoff,"%li",fOffValue);

          fSetter->Execute(fObject, state ? stringon:stringoff);
          fState=state;
          fValue= ( state ? fOnValue : fOffValue);
       }
    }

    //______________________________________________________________________________
     void TToggle::SetValue(Long_t val)
    {
       // Sets the value of toggle and modifies its state according to whether
       // the value is equal to fOnValue.

       if (fInitialized) {
          char stringval[7];
          sprintf(stringval,"%li",val);
          fSetter->Execute(fObject, stringval);
          fState=(val==fOnValue);
          fValue= val;
       }
    }

    //______________________________________________________________________________
     void TToggle::Toggle()
    {
       // Toggles the Values and State of this object and connected data!

       if (fInitialized){
          if (fTglVariable){
             *fTglVariable = !(*fTglVariable);
             fValue=(*fTglVariable);
             fState=*fTglVariable;
          }
          if (fGetter && fSetter){
             fGetter->Execute(fObject,fValue);
             fValue=( (fValue==fOnValue) ? fOffValue:fOnValue);
             fState=(!(fValue!=fOnValue));
             char stringon[7];
             sprintf(stringon,"%li",fValue);
             fSetter->Execute(fObject, stringon);
          }
       }
    }

    //______________________________________________________________________________
     void TToggle::SetToggledObject(TObject *obj, TMethod *anymethod)
    {
       // Initializes it to toggle an object's datamember using this object's
       // method.

       fObject = obj;
       TDataMember *m = anymethod->FindDataMember();
       if (!m) {
          // try to see if the TMethod has a getter associated via the *GETTER=
          // comment string
          if (anymethod->GetterMethod()) {
             fGetter = anymethod->GetterMethod();
             fSetter = anymethod->SetterMethod();
             fInitialized = 1;
          } else
             Error("SetToggledObject", "cannot determine getter method for %s", anymethod->GetName());
       } else {
          fGetter = m->GetterMethod(obj->IsA());
          fSetter = m->SetterMethod(obj->IsA());
          fInitialized = 1;
       }
    }