| # Gaudi Framework, version v22r4 |

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Public Member Functions | Protected Member Functions | Private Member Functions | Private Attributes

# GaudiHandle< T > Class Template Reference

Handle to be used in lieu of naked pointers to gaudis. More...

`#include <GaudiKernel/GaudiHandle.h>`

Inheritance diagram for GaudiHandle< T >:
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Collaboration diagram for GaudiHandle< T >:
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List of all members.

## Public Member Functions
| GaudiHandle (const GaudiHandle &other)
| Copy constructor needed for correct ref-counting.
GaudiHandle & | operator= (const GaudiHandle &other)
| Assignment operator for correct ref-counting.
StatusCode | retrieve () const
| Retrieve the component.
StatusCode | release () const
| Release the component.
| operator bool () const
| For testing if handle has component.
T & | operator* ()
T * | operator-> ()
T & | operator* () const
T * | operator-> () const
std::string | getDefaultType ()
| Helper function to get default type string from the class type.
std::string | getDefaultName ()
## Protected Member Functions
| GaudiHandle (const std::string &myTypeAndName, const std::string &myComponentType, const std::string &myParentName)
virtual StatusCode | retrieve (T *&) const =0
| Retrieve the component.
virtual StatusCode | release (T *comp) const
| Release the component.
## Private Member Functions
void | setDefaultTypeAndName ()
| Helper function to set default name and type.
void | setDefaultType ()
| Helper function to set default type from the class type T.
bool | getObject () const
| Load the pointer to the component.
void | assertObject () const
| Load the pointer to the component.
## Private Attributes
T * | m_pObject

## Detailed Description

### template<class T>
class GaudiHandle< T >

Handle to be used in lieu of naked pointers to gaudis.

This allows better control through the framework of gaudi loading and usage. T is the type of the component interface (or concrete class).

Author:
  Martin.Woudstra@cern.ch

Definition at line 158 of file GaudiHandle.h.

## Constructor & Destructor Documentation

template<class T>

GaudiHandle< T >::GaudiHandle | ( | const std::string & | myTypeAndName,
|  | const std::string & | myComponentType,
|  | const std::string & | myParentName
| ) |  | `[inline, protected]`

Definition at line 163 of file GaudiHandle.h.

        : GaudiHandleBase(myTypeAndName, myComponentType, myParentName), m_pObject(0)
      {}

template<class T>

GaudiHandle< T >::GaudiHandle | ( | const GaudiHandle< T > & | other ) | `[inline]`

Copy constructor needed for correct ref-counting.

Definition at line 170 of file GaudiHandle.h.

        : GaudiHandleBase( other ) {
        m_pObject = other.m_pObject;
        if ( m_pObject ) m_pObject->addRef();
      }

## Member Function Documentation

template<class T>

void GaudiHandle< T >::assertObject | ( | ) | const`[inline, private]`

Load the pointer to the component.

Do a retrieve if needed. Throw an exception if retrieval fails.

Definition at line 274 of file GaudiHandle.h.

                                { // not really const, because it may update m_pObject
        if ( !getObject() ) {
          throw GaudiException("Failed to retrieve " + componentType() + ": " + typeAndName(),
                               componentType() + " retrieve", StatusCode::FAILURE);
        }
      }

template<class T>

std::string GaudiHandle< T >::getDefaultName | ( | ) | `[inline]`

Definition at line 238 of file GaudiHandle.h.

                                 {
        std::string defName = GaudiHandleBase::type();
        if ( defName.empty() ) defName = getDefaultType();
        return defName;
      }

template<class T>

std::string GaudiHandle< T >::getDefaultType | ( | ) | `[inline]`

Helper function to get default type string from the class type.

Definition at line 234 of file GaudiHandle.h.

                                 {
        return System::typeinfoName( typeid(T) );
      }

template<class T>

bool GaudiHandle< T >::getObject | ( | ) | const`[inline, private]`

Load the pointer to the component.

Do a retrieve if needed

Definition at line 268 of file GaudiHandle.h.

                             { // not really const, because it may update m_pObject
        return m_pObject || retrieve().isSuccess();
      }

template<class T>

GaudiHandle< T >::operator bool | ( | ) | const`[inline]`

For testing if handle has component.

Does retrieve() if needed. If this returns false, the component could not be retrieved.

Definition at line 209 of file GaudiHandle.h.

                            { // not really const, because it may update m_pObject
        return getObject();
      }

template<class T>

T& GaudiHandle< T >::operator* | ( | ) | `[inline]`

Definition at line 213 of file GaudiHandle.h.

                     {
        assertObject();
        return *m_pObject;
      }

template<class T>

T& GaudiHandle< T >::operator* | ( | ) | const`[inline]`

Definition at line 223 of file GaudiHandle.h.

                           { // not really const, because it may update m_pObject
        assertObject();
        return *m_pObject;
      }

template<class T>

T* GaudiHandle< T >::operator-> | ( | ) | const`[inline]`

Definition at line 228 of file GaudiHandle.h.

                            { // not really const, because it may update m_pObject
        assertObject();
        return m_pObject;
      }

template<class T>

T* GaudiHandle< T >::operator-> | ( | ) | `[inline]`

Definition at line 218 of file GaudiHandle.h.

                      {
        assertObject();
        return m_pObject;
      }

template<class T>

GaudiHandle& GaudiHandle< T >::operator= | ( | const GaudiHandle< T > & | other ) | `[inline]`

Assignment operator for correct ref-counting.

Definition at line 177 of file GaudiHandle.h.

                                                         {
        GaudiHandleBase::operator=( other );
        // release any current tool
        release().ignore();
        m_pObject = other.m_pObject;
        // update ref-counting
        if ( m_pObject ) m_pObject->addRef();
        return *this;
      }

template<class T>

virtual StatusCode GaudiHandle< T >::release | ( | T * | comp ) | const`[inline, protected, virtual]`

Release the component.

Default implementation calls release() on the component. Can be overridden by the derived class if something else if needed.

Reimplemented in ToolHandle< T >.

Definition at line 250 of file GaudiHandle.h.

                                                  { // not really const, because it updates m_pObject
        comp->release();
        return StatusCode::SUCCESS;
      }

template<class T>

StatusCode GaudiHandle< T >::release | ( | ) | const`[inline]`

Release the component.

Reimplemented in ToolHandle< T >.

Definition at line 198 of file GaudiHandle.h.

                                 { // not really const, because it updates m_pObject
        if ( m_pObject ) {
          StatusCode sc = release( m_pObject );
          m_pObject = 0;
          return sc;
        }
        return StatusCode::SUCCESS;
      }

template<class T>

StatusCode GaudiHandle< T >::retrieve | ( | ) | const`[inline]`

Retrieve the component.

Release existing component if needed.

Reimplemented in ServiceHandle< T >, ToolHandle< T >, and ServiceHandle< IToolSvc >.

Definition at line 188 of file GaudiHandle.h.

                                  { // not really const, because it updates m_pObject
        if ( m_pObject && release().isFailure() ) return StatusCode::FAILURE;
        if ( retrieve( m_pObject ).isFailure() ) {
          m_pObject = 0;
          return StatusCode::FAILURE;
        }
        return StatusCode::SUCCESS;
      }

template<class T>

virtual StatusCode GaudiHandle< T >::retrieve | ( | T *& | ) | const`[protected, pure virtual]`

Retrieve the component.

To be implemented by the derived class. It will pass the pointer

Implemented in ServiceHandle< T >, ToolHandle< T >, and ServiceHandle< IToolSvc >.

template<class T>

void GaudiHandle< T >::setDefaultType | ( | ) | `[inline, private]`

Helper function to set default type from the class type T.

Definition at line 263 of file GaudiHandle.h.

                            {
        GaudiHandleBase::setTypeAndName( getDefaultType() );
      }

template<class T>

void GaudiHandle< T >::setDefaultTypeAndName | ( | ) | `[inline, private]`

Helper function to set default name and type.

Definition at line 257 of file GaudiHandle.h.

                                   {
        const std::string& myType = getDefaultType();
        GaudiHandleBase::setTypeAndName(myType+'/'+myType);
      }

## Member Data Documentation

template<class T>

T* GaudiHandle< T >::m_pObject`[mutable, private]`

Definition at line 283 of file GaudiHandle.h.

The documentation for this class was generated from the following file:

- /afs/cern.ch/sw/Gaudi/releases/GAUDI/GAUDI_v22r4/GaudiKernel/GaudiKernel/GaudiHandle.h

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