Class ComponentBase

• Defined in File component.hpp

Derived Types

• public holoscan::Component (Class Component)

• public holoscan::Operator (Class Operator)

class ComponentBase

Base class for all components.

This class is the base class for all components including holoscan::Operator, holoscan::Condition, and holoscan::Resource. It is used to define the common interface for all components.

Subclassed by holoscan::Component, holoscan::Operator

Public Functions

ComponentBase() = default

template<typename ArgT, typename ...ArgsT, typename = std::enable_if_t<!std::is_base_of_v<::holoscan::ComponentBase, std::decay_t<ArgT>> && (std::is_same_v<::holoscan::Arg, std::decay_t<ArgT>> || std::is_same_v<::holoscan::ArgList, std::decay_t<ArgT>>)>>
inline explicit ComponentBase(ArgT &&arg, ArgsT&&... args)

Construct a new Component object.

Parameters

args – The arguments to be passed to the component.

virtual ~ComponentBase() = default

inline int64_t id() const

Get the identifier of the component.

By default, the identifier is set to -1. It is set to a valid value when the component is initialized.

With the default executor (GXFExecutor), the identifier is set to the GXF component ID.

Returns

The identifier of the component.

inline const std::string &name() const

Get the name of the component.

Returns

The name of the component.

inline Fragment *fragment()

Get a pointer to Fragment object.

Returns

The Pointer to Fragment object.

inline void add_arg(const Arg &arg)

Add an argument to the component.

Parameters

arg – The argument to add.

inline void add_arg(Arg &&arg)

Add an argument to the component.

Parameters

arg – The argument to add.

inline void add_arg(const ArgList &arg)

Add a list of arguments to the component.

Parameters

arg – The list of arguments to add.

inline void add_arg(ArgList &&arg)

Add a list of arguments to the component.

Parameters

arg – The list of arguments to add.

inline std::vector<Arg> &args()

Get the list of arguments.

Returns

The vector of arguments.

inline virtual void initialize()

Initialize the component.

This method is called only once when the component is created for the first time, and use of light-weight initialization.

virtual YAML::Node to_yaml_node() const

Get a YAML representation of the component.

Returns

YAML node including the id, name, fragment name, and arguments of the component.

std::string description() const

Get a description of the component.

See also

to_yaml_node()

Returns

YAML string.

Public Static Functions

template<typename typeT>
static inline void register_converter()

Register the argument setter for the given type.

If an operator or resource has an argument with a custom type, the argument setter must be registered using this method.

The argument setter is used to set the value of the argument from the YAML configuration.

This method can be called in the initialization phase of the operator/resource (e.g., initialize()). The example below shows how to register the argument setter for the custom type (Vec3):

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void MyOp::initialize() {
  register_converter<Vec3>();
}
        

It is assumed that YAML::convert<T>::encode and YAML::convert<T>::decode are implemented for the given type. You need to specialize the YAML::convert<> template class.

For example, suppose that you had a Vec3 class with the following members:

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struct Vec3 {
  // make sure you have overloaded operator==() for the comparison
  double x, y, z;
};
        

You can define the YAML::convert<Vec3> as follows in a ‘.cpp’ file:

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namespace YAML {
template<>
struct convert<Vec3> {
  static Node encode(const Vec3& rhs) {
    Node node;
    node.push_back(rhs.x);
    node.push_back(rhs.y);
    node.push_back(rhs.z);
    return node;
  }

  static bool decode(const Node& node, Vec3& rhs) {
    if(!node.IsSequence() || node.size() != 3) {
      return false;
    }

    rhs.x = node[0].as<double>();
    rhs.y = node[1].as<double>();
    rhs.z = node[2].as<double>();
    return true;
  }
};
}
        

Please refer to the yaml-cpp documentation for more details.

Template Parameters

typeT – The type of the argument to register.

Protected Functions

void update_params_from_args(std::unordered_map<std::string, ParameterWrapper> &params)

Update parameters based on the specified arguments.

virtual void reset_graph_entities()

Reset the GXF GraphEntity of any arguments that have one.

Protected Attributes

int64_t id_ = -1

The ID of the component.

std::string name_ = ""

Name of the component.

Fragment *fragment_ = nullptr

Pointer to the fragment that owns this component.

std::vector<Arg> args_

List of arguments.

Protected Static Functions

template<typename typeT>
static void register_argument_setter()

Register the argument setter for the given type.

Please refer to the documentation of register_converter() for more details.

Template Parameters

typeT – The type of the argument to register.

Friends

friend class holoscan::Executor

friend class holoscan::gxf::GXFExecutor

friend class holoscan::Fragment