Provides a generic Factory class. More...

#include <NekFactory.hpp>

Classes
struct	ModuleEntry
	Define a struct to hold the information about a module. More...

Public Types
typedef std::less< tKey >	tPredicator
	Comparison predicator of key. More...

typedef std::shared_ptr< tBase >	tBaseSharedPtr
	Shared pointer to an object of baseclass type. More...

typedef tBaseSharedPtr(*	CreatorFunction) (tParam...)
	CreatorFunction type which takes parameter and returns base class shared pointer. More...

typedef std::map< tKey, ModuleEntry, tPredicator >	TMapFactory
	Factory map between key and module data. More...

Public Member Functions
	NekFactory ()=default

tBaseSharedPtr	CreateInstance (tKey idKey, tParam... args)
	Create an instance of the class referred to by `idKey`. More...

tKey	RegisterCreatorFunction (tKey idKey, CreatorFunction classCreator, std::string pDesc="")
	Register a class with the factory. More...

bool	ModuleExists (tKey idKey)
	Checks if a particular module is available. More...

void	PrintAvailableClasses (std::ostream &pOut=std::cout)
	Prints the available classes to stdout. More...

tKey	GetKey (std::string pDesc)
	Retrieves a key, given a description. More...

std::string	GetClassDescription (tKey idKey)
	Returns the description of a class. More...

Protected Member Functions
TMapFactory *	getMapFactory ()
	Ensure the factory's map is created. More...

Private Member Functions
	NekFactory (const NekFactory &rhs)

NekFactory &	operator= (const NekFactory &rhs)

Private Attributes
TMapFactory	mMapFactory

Detailed Description

template<typename tKey, typename tBase, typename... tParam>
class Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >

Provides a generic Factory class.

Implements a generic object factory. Class-types which use an arbitrary number of parameters may be used via C++ variadic templating.

To allow a class to be instantiated by the factory, the following are required in each class definition (in the case of a single parameter):

static [baseclass]* create([paramtype1] &P) {
   return new [derivedclass](P);
}
static std::string className;

and outside the class definition in the implementation:

std::string [derivedclass]::className
   = Factory<std::string,[baseclass],[paramtype1]>::
       RegisterCreatorFunction("[derivedclass]",
                           [derivedclass]::create,"Description");

The assignment of the static variable className is done through the call to RegisterCreatorFunction, which registers the class with the factory prior to the start of the main() routine.

To create an instance of a derived class, for instance:

[baseclass]* var_name =
   Factory<std::string,[baseclass],[paramtype1]>
           ::CreateInstance("[derivedclass]",Param1);

Definition at line 103 of file NekFactory.hpp.

Member Typedef Documentation

◆ CreatorFunction

template<typename tKey , typename tBase , typename... tParam>

typedef tBaseSharedPtr(* Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::CreatorFunction) (tParam...)

CreatorFunction type which takes parameter and returns base class shared pointer.

Definition at line 112 of file NekFactory.hpp.

◆ tBaseSharedPtr

template<typename tKey , typename tBase , typename... tParam>

typedef std::shared_ptr<tBase> Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::tBaseSharedPtr

Shared pointer to an object of baseclass type.

Definition at line 109 of file NekFactory.hpp.

◆ TMapFactory

template<typename tKey , typename tBase , typename... tParam>

typedef std::map<tKey, ModuleEntry, tPredicator> Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::TMapFactory

Factory map between key and module data.

Definition at line 130 of file NekFactory.hpp.

◆ tPredicator

template<typename tKey , typename tBase , typename... tParam>

typedef std::less<tKey> Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::tPredicator

Comparison predicator of key.

Definition at line 107 of file NekFactory.hpp.

Constructor & Destructor Documentation

◆ NekFactory() [1/2]

template<typename tKey , typename tBase , typename... tParam>

Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::NekFactory ( )

default

Referenced by Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::getMapFactory().

◆ NekFactory() [2/2]

template<typename tKey , typename tBase , typename... tParam>

Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::NekFactory ( const NekFactory< tKey, tBase, tParam > & rhs )

private

Member Function Documentation

◆ CreateInstance()

template<typename tKey , typename tBase , typename... tParam>

tBaseSharedPtr Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::CreateInstance	(	tKey	idKey,
		tParam...	args
	)

inline

Create an instance of the class referred to by idKey.

Searches the factory's map for the given key and returns a shared base class pointer to a new instance of the associated class.

Parameters

idKey	Key of class to create.
x	Parameter to pass to class constructor.

Returns: Base class pointer to new instance.

Definition at line 144 of file NekFactory.hpp.

References Nektar::ErrorUtil::efatal, Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::getMapFactory(), Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::ModuleEntry::m_func, NEKERROR, and Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::PrintAvailableClasses().

     {
 #ifdef NEKTAR_USE_THREAD_SAFETY
         ReadLock vReadLock(m_mutex);
 #endif
 
         // Now try and find the key in the map.
         auto it = getMapFactory()->find(idKey);
 
         // If successful, check the CreatorFunction is defined and
         // create a new instance of the class.
         if (it != getMapFactory()->end())
         {
             ModuleEntry *tmp = &(it->second);
 #ifdef NEKTAR_USE_THREAD_SAFETY
             vReadLock.unlock();
 #endif
 
             if (tmp->m_func)
             {
                 try
                 {
                     return tmp->m_func(args...);
                 }
                 catch (const std::string& s)
                 {
                     std::stringstream errstr;
                     errstr << "Unable to create module: " << idKey << "\n";
                     errstr << s;
                     NEKERROR(ErrorUtil::efatal, errstr.str());
                 }
             }
         }
 
         // If we get this far, the key doesn't exist, so throw an error.
         std::stringstream errstr;
         errstr << "No such module: " << idKey << std::endl;
         PrintAvailableClasses(errstr);
         NEKERROR(ErrorUtil::efatal, errstr.str());
         return tBaseSharedPtr();
     }

◆ GetClassDescription()

template<typename tKey , typename tBase , typename... tParam>

std::string Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::GetClassDescription ( tKey idKey )

inline

Returns the description of a class.

Definition at line 282 of file NekFactory.hpp.

References ASSERTL0, and Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::getMapFactory().

     {
 #ifdef NEKTAR_USE_THREAD_SAFETY
         ReadLock vReadLock(m_mutex);
 #endif
 
         // Now try and find the key in the map.
         auto it = getMapFactory()->find(idKey);
 
         std::stringstream errstr;
         errstr << "No such module: " << idKey << std::endl;
         ASSERTL0 (it != getMapFactory()->end(), errstr.str());
         return it->second.m_desc;
     }

◆ GetKey()

template<typename tKey , typename tBase , typename... tParam>

tKey Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::GetKey ( std::string pDesc )

inline

Retrieves a key, given a description.

Definition at line 261 of file NekFactory.hpp.

References ASSERTL0, and Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::getMapFactory().

     {
 #ifdef NEKTAR_USE_THREAD_SAFETY
         ReadLock vReadLock(m_mutex);
 #endif
 
         for (auto &it : *getMapFactory())
         {
             if (it.second.m_desc == pDesc)
             {
                 return it.first;
             }
         }
         std::string errstr = "Module '" + pDesc + "' is not known.";
         ASSERTL0(false, errstr);
     }

◆ getMapFactory()

template<typename tKey , typename tBase , typename... tParam>

TMapFactory* Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::getMapFactory ( )

inlineprotected

Ensure the factory's map is created.

Returns: The factory's map.

Definition at line 302 of file NekFactory.hpp.

References Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::mMapFactory, Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::NekFactory(), Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::operator=(), and Nektar::rhs.

Referenced by Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::CreateInstance(), Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::GetClassDescription(), Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::GetKey(), Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::ModuleExists(), Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::PrintAvailableClasses(), and Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::RegisterCreatorFunction().

     {
         return &mMapFactory;
     }

◆ ModuleExists()

template<typename tKey , typename tBase , typename... tParam>

bool Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::ModuleExists ( tKey idKey )

inline

Checks if a particular module is available.

Definition at line 215 of file NekFactory.hpp.

References Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::getMapFactory().

Referenced by Nektar::LibUtilities::SessionReader::CreateComm(), main(), and Nektar::SpatialDomains::MeshGraphHDF5::PartitionMesh().

     {
 #ifdef NEKTAR_USE_THREAD_SAFETY
         ReadLock vReadLock(m_mutex);
 #endif
 
         // Now try and find the key in the map.
         auto it = getMapFactory()->find(idKey);
 
         if (it != getMapFactory()->end())
         {
             return true;
         }
         return false;
     }

◆ operator=()

template<typename tKey , typename tBase , typename... tParam>

NekFactory& Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::operator= ( const NekFactory< tKey, tBase, tParam > & rhs )

private

Referenced by Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::getMapFactory().

◆ PrintAvailableClasses()

template<typename tKey , typename tBase , typename... tParam>

void Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::PrintAvailableClasses ( std::ostream & pOut = std::cout )

inline

Prints the available classes to stdout.

Definition at line 235 of file NekFactory.hpp.

References Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::getMapFactory().

Referenced by Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::CreateInstance(), and main().

     {
 #ifdef NEKTAR_USE_THREAD_SAFETY
         ReadLock vReadLock(m_mutex);
 #endif
 
         pOut << std::endl << "Available classes: " << std::endl;
         for (auto &it : *getMapFactory())
         {
             pOut << "  " << it.first;
             if (it.second.m_desc != "")
             {
                 pOut << ":" << std::endl << "    "
                      << it.second.m_desc << std::endl;
             }
             else
             {
                 pOut << std::endl;
             }
         }
     }

◆ RegisterCreatorFunction()

template<typename tKey , typename tBase , typename... tParam>

tKey Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::RegisterCreatorFunction	(	tKey	idKey,
		CreatorFunction	classCreator,
		std::string	pDesc = `""`
	)

inline

Register a class with the factory.

This function is called by each class in a static context (prior to the execution of main()) and creates an entry for the class in the factory's map.

Parameters

idKey	Key used to reference the class.
classCreator	Function to call to create an instance of this class.
pDesc	Optional description of class.

Returns: The given key idKey.

Definition at line 199 of file NekFactory.hpp.

References Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::getMapFactory().

     {
 #ifdef NEKTAR_USE_THREAD_SAFETY
         WriteLock vWriteLock(m_mutex);
 #endif
 
         ModuleEntry e(classCreator, pDesc);
         getMapFactory()->insert(std::pair<tKey,ModuleEntry>(idKey, e));
         return idKey;
     }

Member Data Documentation

◆ mMapFactory

template<typename tKey , typename tBase , typename... tParam>

TMapFactory Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::mMapFactory

private

Definition at line 311 of file NekFactory.hpp.

Referenced by Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >::getMapFactory().

Classes

Public Types

Public Member Functions

Protected Member Functions

Private Member Functions

Private Attributes

Detailed Description

template<typename tKey, typename tBase, typename... tParam> class Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >

Member Typedef Documentation

◆ CreatorFunction

◆ tBaseSharedPtr

◆ TMapFactory

◆ tPredicator

Constructor & Destructor Documentation

◆ NekFactory() [1/2]

◆ NekFactory() [2/2]

Member Function Documentation

◆ CreateInstance()

◆ GetClassDescription()

◆ GetKey()

◆ getMapFactory()

◆ ModuleExists()

◆ operator=()

◆ PrintAvailableClasses()

◆ RegisterCreatorFunction()

Member Data Documentation

◆ mMapFactory

template<typename tKey, typename tBase, typename... tParam>
class Nektar::LibUtilities::NekFactory< tKey, tBase, tParam >