一种实现方式是将类“名称”硬编码映射到工厂函数。使用模板可以使代码更短。STL可以使编码更容易。
#include "BaseObject.h"
#include "CommonClasses.h"
template< typename T > BaseObject* fCreate( int param1, bool param2 ) {
return new T( param1, param2 );
}
typedef BaseObject* (*tConstructor)( int param1, bool param2 );
struct Mapping { string classname; tConstructor constructor;
pair<string,tConstructor> makepair()const {
return make_pair( classname, constructor );
}
} mapping[] =
{ { "class1", &fCreate<Class1> }
, { "class2", &fCreate<Class2> }
};
map< string, constructor > constructors;
transform( mapping, mapping+_countof(mapping),
inserter( constructors, constructors.begin() ),
mem_fun_ref( &Mapping::makepair ) );
编辑--根据普遍要求:)稍微重新调整一下,使事情看起来更加流畅(感谢Stone Free,他可能不想自己添加答案)
typedef BaseObject* (*tConstructor)( int param1, bool param2 );
struct Mapping {
string classname;
tConstructor constructor;
operator pair<string,tConstructor> () const {
return make_pair( classname, constructor );
}
} mapping[] =
{ { "class1", &fCreate<Class1> }
, { "class2", &fCreate<Class2> }
};
static const map< string, constructor > constructors(
begin(mapping), end(mapping) );