dds::core::xtypes::DynamicType Class Reference

<<value-type>> Represents a runtime type. More...

#include "dds/core/xtypes/DynamicType.hpp"

Inheritance diagram for dds::core::xtypes::DynamicType:

Public Member Functions
dds::core::xtypes::TypeKind	kind () const
	Gets the type kind.
std::string	name () const
	Gets the name.

Related Functions
(Note that these are not member functions.)
bool	is_primitive_type (const DynamicType &t)
	Determines if a DynamicType is a PrimitiveType.
bool	is_constructed_type (const DynamicType &t)
	Determines if a DynamicType is a constructed type.
bool	is_collection_type (const DynamicType &t)
	Determines if a DynamicType is a CollectionType.
bool	is_aggregation_type (const DynamicType &t)
	Determines if a DynamicType is an aggregation type.
void	print_idl (const DynamicType &type, unsigned int indent=0)
	<<extension>> Prints the IDL representation of this type to the standard output

Detailed Description

<<value-type>> Represents a runtime type.

A DynamicType is a mechanism for representing a type at runtime. DynamicTypes allow the reflective manipulation of data (DynamicData) and the inspection of the type information about discovered readers and writers.

You can obtain a DynamicType in a few different ways:

1. Creating one by instantiating a subclass of dds::core::xtypes::DynamicType instance, such as dds::core::xtypes::StructType and adding members to it. For example:

   using namespace dds::core::xtypes;
   
   StructType point_type("Point");
   point_type.add_member(Member("x", PrimitiveType<double>()));
   point_type.add_member(Member("y", PrimitiveType<double>()));

2. From an IDL-generated type, using the rti::topic::dynamic_type trait type. <<extension>>
3. From an XML description, using dds::core::QosProvider::type().
4. Constructing it using tuples. <<C++11>> <<experimental>> <<extension>>
5. From a discovered DataReader or DataWriter, using the built-in topics.

For examples, see DynamicType and DynamicData Use Cases

This an abstract base class of all the types. This class contains all of the internal state—derived classes don't add any new state. That means that it is safe to copy a DynamicType without slicing.

To downcast a DynamicType into a concrete class, you can check its kind() and then apply a static_cast to the appropriate class.

For example, let's assume we have the following IDL type:

struct Bar {
    long x;
};

struct Foo {
    Bar bar;
    long y;
};

We obtain the type of Foo and want to know the type of its member bar:

// Get the DynamicType of the IDL-generated type Foo
const StructType& foo_type = rti::topic::dynamic_type<Foo>::get();
// Get the type of its member bar
const DynamicType& bar_type = foo_type.member("bar").type();
// Check type kind and downcast
if (bar_type.kind() == TypeKind::STRUCTURE_TYPE) {
    const StructType& bar_struct = static_cast<const StructType&>(bar_type);
}

See Also

dds::core::xtypes::DynamicData, the class that represents data samples for a DynamicType

dds::topic::SubscriptionBuiltinTopicData::type() and dds::topic::PublicationBuiltinTopicData::type() to obtain the type of a remote subscription or publication

rti::topic::dynamic_type to obtain the equivalent DynamicType of an IDL-generated type

DynamicType and DynamicData Use Cases

Member Function Documentation

dds::core::xtypes::TypeKind dds::core::xtypes::DynamicType::kind

(

)

const

Gets the type kind.

std::string dds::core::xtypes::DynamicType::name

(

)

const

Gets the name.

Friends And Related Function Documentation

bool is_primitive_type ( const DynamicType &  t )

related

Determines if a DynamicType is a PrimitiveType.

bool is_constructed_type ( const DynamicType &  t )

related

Determines if a DynamicType is a constructed type.

This includes EnumType, AliasType, collection types and aggregation types.

See Also

is_collection_type

is_aggregation_type

bool is_collection_type ( const DynamicType &  t )

related

Determines if a DynamicType is a CollectionType.

This includes ArrayType, SequenceType, StringType, and WStringType.

bool is_aggregation_type ( const DynamicType &  t )

related

Determines if a DynamicType is an aggregation type.

This includes StructType and UnionType.

void print_idl ( const DynamicType &  type, unsigned int  indent = 0  )

related

<<extension>> Prints the IDL representation of this type to the standard output