JTreeParameters.hh

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#ifndef __JROOT__JTREEPARAMETERS__
#define __JROOT__JTREEPARAMETERS__

#include "TString.h"

#include "JLang/JType.hh"
#include "JLang/JNullType.hh"


/**
 * \author mdejong
 */

namespace JROOT {}
namespace JPP { using namespace JROOT; }

namespace JROOT {

  using JLANG::JType;
  using JLANG::JNullType;


  /**
   * Data structure for TTree parameters.
   */
  class JTreeParameters {
  public:
    /**
     * Constructor.
     *
     * \param  treeName            TTree   name
     * \param  treeTitle           TTree   title
     * \param  branchName          TBranch name
     * \param  compressionLevel    TBranch compression level
     * \param  basketSize          TBranch basket size
     * \param  splitLevel          TBranch split level
     */
    JTreeParameters(const TString& treeName,
                    const TString& treeTitle,
                    const TString& branchName       = "",
                    const int      compressionLevel =     1,
                    const int      basketSize       = 65536,
                    const int      splitLevel       =     1)
                    
    {
      this->treeName         = treeName;
      this->treeTitle        = treeTitle;
      this->branchName       = branchName;
      this->compressionLevel = compressionLevel;
      this->basketSize       = basketSize;
      this->splitLevel       = splitLevel;
    }


    /**
     * Get TTree parameters.
     *
     * \return        TTree parameters
     */
    inline const JTreeParameters& getTreeParameters() const
    {
      return static_cast<const JTreeParameters&>(*this);
    }


    /**
     * Get TTree name.
     *
     * \return        TTree name
     */
    const TString& getTreeName() const 
    {
      return treeName;
    }


    /**
     * Get TTree title.
     *
     * \return        TTree title
     */
    const TString& getTreeTitle() const 
    {
      return treeTitle;
    }


    /**
     * Get TBranch name.
     *
     * \return        TBranch name
     */
    const TString& getBranchName() const 
    {
      return (branchName != "" ? branchName : treeName);
    }


    /**
     * Get compression level.
     *
     * \return        compression level
     */
    int getCompressionLevel() const 
    {
      return compressionLevel;
    }


    /**
     * Get basket size.
     *
     * \return        basket size
     */
    int getBasketSize() const 
    {
      return basketSize;
    }


    /**
     * Get split level.
     *
     * \return        split level
     */
    int getSplitLevel() const 
    {
      return splitLevel;
    }


  protected:
    TString  treeName;           //!< TTree   name
    TString  treeTitle;          //!< TTree   title
    TString  branchName;         //!< TBranch name
    int      compressionLevel;   //!< TBranch compression level
    int      basketSize;         //!< TBranch basket size
    int      splitLevel;         //!< TBranch split level
  };


  /**
   * Template definition for method returning TTree parameters.
   * The template argument refers to the class for which ROOT TTree I/O is desired.
   *
   * \return        TTree parameters
   */
  template<class T>
  inline JTreeParameters getTreeParameters() 
  {
    return getTreeParameters(JType<T>());
  }


  /**
   * Method with argument definition for obtaining TTree parameters.
   * The method argument refers to the class for which ROOT TTree I/O is desired.
   * This method should then be overloaded and the overloaded method should
   * return a JTreeParameters object with the corresponding TTree parameters.
   *
   * \param  type   data type
   * \return        TTree parameters
   */
  template<class T>
  inline JNullType getTreeParameters(const JType<T>& type);


  /**
   * Test availability of TTree parameters for given class.
   *
   * The parameter result evaluates to true if for this class TTree parameters are defined.
   */
  template<class T>
  class JTreeParametersAvailable
  {
  private:
    
    class JSmall { char buffer; };
    class JBig   { int  buffer; };
    
    static JBig   JTest(...); 
    static JSmall JTest(const JTreeParameters&);
    
  public:
    static const bool result = sizeof(JTest(getTreeParameters(JType<T>()))) == sizeof(JSmall); //!< true if TTree parameters available; else false
  };
}

#endif