Utils::Factory< T > Class Template Reference

Factory template. More...

#include <Factory.hpp>

Public Types
using	pointer_type = std::unique_ptr< T >
	The returned pointer type.
using	builder_type = pointer_type(*)()
	Type of the constructor functions.

Public Member Functions
pointer_type	make (const std::string &name) const
	Construct an instance by name.
bool	has_builder (const std::string &name) const
	Check if the factory knows how to make name.
template<typename Derived >
void	register_new (const std::string &name)
	Register a new type with the default construction function.
const std::string &	type_name (T const &o) const
	Look up name for type.

Detailed Description

template<class T>
class Utils::Factory< T >

Factory template.

Can be used to construct registered instances of classes derived from the base type (T) by name. One registry per base type (T). To get a new one, use new type ( struct NewT : public T {}; ). To add a new type it has to be given a name an a function of type Factory<T>::builder_type to create an instance has to be provided. The class contains a default implementation for the creation function (Factory<T>::builder<Derived>) which just calls new to create an instance. A user provided function could be used to use a non-default constructor, or to allocate memory for the instance in a specific way, e.g. by placing all new instances in a vector.

Example usage:

struct A {};
struct B : public A {};
struct C : public A {
  C(int c) : m_c(c) {}
  int m_c;
};
 
// Register B as 'b' with default builder:
Factory<A>::register_new<B>("b");
// Register C as 'c' with user_defined builder:
Factory<A>::register_new("c", []() -> typename Factory<A>::pointer_type {
    return new C(5); });
 
// Create a B
auto b = Factory<A>::make("b");
assert(dynamic_cast<B *>(b.get()));
 
// Create a C
auto c = Factory<A>::make("c");
assert(dynamic_cast<C *>(c.get())->m_c == 5);

Definition at line 78 of file Factory.hpp.

Member Typedef Documentation

builder_type

template<class T >

using Utils::Factory< T >::builder_type = pointer_type (*)()

Type of the constructor functions.

Definition at line 83 of file Factory.hpp.

pointer_type

template<class T >

using Utils::Factory< T >::pointer_type = std::unique_ptr<T>

The returned pointer type.

Definition at line 81 of file Factory.hpp.

Member Function Documentation

has_builder()

template<class T >

bool Utils::Factory< T >::has_builder ( const std::string &  name ) const

inline

Check if the factory knows how to make name.

Parameters

name	Given name to check.

Returns

Whether we know how to make a name.

Definition at line 104 of file Factory.hpp.

make()

template<class T >

pointer_type Utils::Factory< T >::make ( const std::string &  name ) const

inline

Construct an instance by name.

Definition at line 89 of file Factory.hpp.

Referenced by ScriptInterface::LocalContext::make_shared().

register_new()

template<class T >

template<typename Derived >

void Utils::Factory< T >::register_new ( const std::string &  name )

inline

Register a new type with the default construction function.

Parameters

name	Given name for the type, has to be unique in this Factory<T>.

Definition at line 113 of file Factory.hpp.

Referenced by ScriptInterface::BondBreakage::initialize(), and ScriptInterface::Shapes::initialize().

type_name()

template<class T >

const std::string & Utils::Factory< T >::type_name ( T const &  o ) const

inline

Look up name for type.

For an object whose type can be created by the factory this returns the name under which it is registered. This will consider the dynamic type of polymorphic objects, e.g. it will return the name of the most derived type.

Parameters

o	Object whose type is to be considered.

Exceptions

std::out_of_range

If the type is not registered.

Returns

Name by which T can be made.

Definition at line 132 of file Factory.hpp.

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

• Factory.hpp