Value< T > Class Template Reference

Detailed Description

template<typename T>
class drake::Value< T >

A container class for an arbitrary type T (with some restrictions).

This class inherits from AbstractValue and therefore at runtime can be passed between functions without mentioning T.

Example:

void print_string(const AbstractValue& arg) {
  const std::string& message = arg.get_value<std::string>();
  std::cerr << message;
}
void meow() {
  const Value<std::string> value("meow");
  print_string(value);
}

(Advanced.) User-defined classes with additional features may subclass Value, but should take care to override Clone().

Template Parameters

T	Must be copy-constructible or cloneable. Must not be a pointer, array, nor have const, volatile, or reference qualifiers.

#include <drake/common/value.h>

Public Member Functions
	Value ()
	Constructs a Value<T> using T's default constructor, if available. More...
	Value (const T &v)
	Constructs a Value<T> by copying or cloning the given value v. More...
template<typename... Args>
	Value (Args &&... args)
	Constructs a Value<T> by forwarding the given args to T's constructor, if available. More...
	Value (std::unique_ptr< T > v)
	Constructs a Value<T> by copying or moving the given value v. More...
	~Value () override=default
const T &	get_value () const
	Returns a const reference to the stored value. More...
T &	get_mutable_value ()
	Returns a mutable reference to the stored value. More...
void	set_value (const T &v)
	Replaces the stored value with a new one. More...
std::unique_ptr< AbstractValue >	Clone () const override
	Returns a copy of this AbstractValue. More...
void	SetFrom (const AbstractValue &other) override
	Copies the value in other to this value. More...
const std::type_info &	type_info () const final
	Returns typeid of the contained object of type T. More...
const std::type_info &	static_type_info () const final
	Returns typeid(T) for this Value<T> object. More...
std::string	GetNiceTypeName () const
	Returns a human-readable name for the underlying type T. More...
virtual const std::type_info &	static_type_info () const=0
	Returns typeid(T) for this Value<T> object. More...
Does not allow copy, move, or assignment
	Value (const Value &)=delete
Value &	operator= (const Value &)=delete
	Value (Value &&)=delete
Value &	operator= (Value &&)=delete
Public Member Functions inherited from AbstractValue
virtual	~AbstractValue ()
template<typename T >
const T &	get_value () const
	Returns the value wrapped in this AbstractValue as a const reference. More...
template<typename T >
T &	get_mutable_value ()
	Returns the value wrapped in this AbstractValue as mutable reference. More...
template<typename T >
void	set_value (const T &v)
	Sets the value wrapped in this AbstractValue. More...
template<typename T >
const T *	maybe_get_value () const
	Returns the value wrapped in this AbstractValue, if T matches the originally declared type of this AbstractValue. More...
template<typename T >
T *	maybe_get_mutable_value ()
	Returns the mutable value wrapped in this AbstractValue, if T matches the originally declared type of this AbstractValue. More...
std::string	GetNiceTypeName () const
	Returns a human-readable name for the underlying type T. More...
	AbstractValue (const AbstractValue &)=delete
AbstractValue &	operator= (const AbstractValue &)=delete
	AbstractValue (AbstractValue &&)=delete
AbstractValue &	operator= (AbstractValue &&)=delete

Additional Inherited Members
Static Public Member Functions inherited from AbstractValue
static std::unique_ptr< AbstractValue >	Make ()
	Constructs an AbstractValue using T's default constructor, if available. More...
template<typename T >
static std::unique_ptr< AbstractValue >	Make (const T &value)
	Returns an AbstractValue containing the given value. More...

Constructor & Destructor Documentation

Value() [1/6]

Value ( const Value< T > &  )

delete

Value() [2/6]

Value ( Value< T > &&  )

delete

Value() [3/6]

Value

(

)

Constructs a Value<T> using T's default constructor, if available.

This is only available for T's that support default construction.

Value() [4/6]

Value ( const T &  v )

explicit

Constructs a Value<T> by copying or cloning the given value v.

Value() [5/6]

Value ( Args &&...  args )

explicit

Constructs a Value<T> by forwarding the given args to T's constructor, if available.

This is only available for non-primitive T's that are constructible from args.

Value() [6/6]

Value ( std::unique_ptr< T >  v )

explicit

Constructs a Value<T> by copying or moving the given value v.

Precondition

v is non-null.

~Value()

~Value ( )

overridedefault

Member Function Documentation

Clone()

std::unique_ptr<AbstractValue> Clone ( ) const

overridevirtual

Returns a copy of this AbstractValue.

Implements AbstractValue.

get_mutable_value()

T& get_mutable_value

(

)

Returns a mutable reference to the stored value.

The reference remains valid only until this object is set or destroyed.

get_value()

const T& get_value

(

)

const

Returns a const reference to the stored value.

The reference remains valid only until this object is set or destroyed.

GetNiceTypeName()

std::string GetNiceTypeName

Returns a human-readable name for the underlying type T.

This may be slow but is useful for error messages. If T is polymorphic, this returns the typeid of the most-derived type of the contained object.

operator=() [1/2]

Value& operator= ( Value< T > &&  )

delete

operator=() [2/2]

Value& operator= ( const Value< T > &  )

delete

set_value()

void set_value

(

const T &

v

)

Replaces the stored value with a new one.

SetFrom()

void SetFrom ( const AbstractValue< T > &  other )

overridevirtual

Copies the value in other to this value.

If other is not compatible with this object, a std::logic_error will be thrown with a helpful error message.

Implements AbstractValue.

static_type_info() [1/2]

const std::type_info& static_type_info ( ) const

finalvirtual

Returns typeid(T) for this Value<T> object.

If T is polymorphic, this does NOT reflect the typeid of the most-derived type of the contained object; the result is always the base type T.

Implements AbstractValue.

static_type_info() [2/2]

virtual const std::type_info& static_type_info

Returns typeid(T) for this Value<T> object.

If T is polymorphic, this does NOT reflect the typeid of the most-derived type of the contained object; the result is always the base type T.

type_info()

const std::type_info& type_info ( ) const

finalvirtual

Returns typeid of the contained object of type T.

If T is polymorphic, this returns the typeid of the most-derived type of the contained object.

Implements AbstractValue.

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

• drake/common/value.h