xtd::iclonable Class Reference

Inheritance diagram for xtd::iclonable:

Definition

Supports cloning, which creates a new instance of a class with the same value as an existing instance.

Namespace

xtd

Library

xtd.core

Remarks

The xtd::iclonable interface enables you to provide a customized implementation that creates a copy of an existing object. The xtd::iclonable interface contains one member, the xtd::iclonable::clone method, which is intended to provide cloning support beyond that supplied by xtd::object::memberwise_clone. For more information about cloning, deep versus shallow copies, and examples, see the xtd::object::memberwise_clone method.

Notes to Implementers

The xtd::iclonable interface simply requires that your implementation of the xtd::iclonable::clone() method return a copy of the current object instance. It does not specify whether the cloning operation performs a deep copy, a shallow copy, or something in between. Nor does it require all property values of the original instance to be copied to the new instance. For example, the xtd::iclonable::clone() method performs a shallow copy of all properties; it always sets this property value to false in the cloned object. Because callers of xtd::iclonable::clone() cannot depend on the method performing a predictable cloning operation, we recommend that xtd::iclonable not be implemented in public APIs. The following example shows how to use xtd::iclonable interface.

#include <xtd/xtd>
 
class foo : public object, public iclonable {
public:
  explicit foo(int value) : value_ {value} {}
 
  uptr<object> clone() const override {return new_uptr<foo>(value_);}
 
  string to_string() const noexcept override {return string::format("{}", value_);}
 
private:
  int value_ = 0;
};
 
auto main() -> int {
  auto f1 = foo {42};
  console::write_line("f1 {{type = {}, value = {}}}", typeof_(f1), f1);
 
  auto f2 = f1.clone();
  console::write_line("f2 {{type = {}, value = {}}}", typeof_(f2), *f2);
 
  auto f3 = as<foo>(f1.clone());
  console::write_line("f3 {{type = {}, value = {}}}", typeof_(f3), *f3);
}
 
// This code produces the following output :
//
// f1 {type = foo, value = 42}
// f2 {type = std::unique_ptr<xtd::object, std::default_delete<xtd::object>>, value = 42}
// f3 {type = std::unique_ptr<foo, std::default_delete<foo>>, value = 42}
 

Public Methods
virtual auto	clone () const -> xtd::uptr< xtd::object >=0
	Creates a new object that is a copy of the current instance.

Member Function Documentation

clone()

virtual auto xtd::iclonable::clone ( ) const -> xtd::uptr< xtd::object >

nodiscardpure virtual

Creates a new object that is a copy of the current instance.

Returns

A new object that is a copy of this instance.

Remarks

The resulting clone must be of the same type as, or compatible with, the original instance.

An implementation of xtd::iclonable::clone can perform either a deep copy or a shallow copy. In a deep copy, all objects are duplicated; in a shallow copy, only the top-level objects are duplicated and the lower levels contain references. Because callers of xtd::iclonable::clone cannot depend on the method performing a predictable cloning operation, we recommend that xtd::iclonable not be implemented in public APIs.

See xtd::object::memberwise_clone for more information on cloning, deep versus shallow copies, and examples.

Implemented in xtd::collections::bit_array.

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

• xtd.core/include/xtd/iclonable.hpp