Coding your own Components

When to decide if your class should be a component?

When it is any or more of the following:

• configurable
• data you want stored and easily accessible from anywhere in the code
• action

Example

A new component always has to inherit from a parent class which is also a component. A simple example is the class common::Group, which adds actually no extra functionality.

namespace cf3 {
namespace common {

class Common_API Group : public Component 
{
public: // functions

  static std::string type_name () { return "Group"; }

  Group ( const std::string& name ) : Component(name) {}

  virtual ~Group() {}

};

} //namespace common
} //namespace cf3

Noteworthy here is:

• Group inherits from Component
• The constructor of a Component takes only 1 std::string, i.e. the name the component gets
• The component must have a static function Group::type_name() defined, returning the class name
• Following the class name is first the API macro related to this namespace (here Common_API). This macro is usually defined in the library of this namespace. (LibNamespace.hpp)

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