Method chaining is a common technique for invoking multiple method calls in object-oriented programming languages

Object-oriented programming

Object-oriented programming is a programming paradigm using "objects" – data structures consisting of data fields and methods together with their interactions – to design applications and computer programs. Programming techniques may include features such as data abstraction,...

. Each method returns an object (possibly the current object itself), allowing the calls to be chained together in a single statement. A method chain is also known as a train wreck due to an increasing amount of methods stacked after another in one line.

C#:

Object.DoSomething.DoSomethingElse.DoAnotherThing;


PHP:

$object->do->something->else


Method chaining is not required. It only potentially improves readability and reduces the amount of source code. It is the core concept behind building a fluent interface

Fluent interface

In software engineering, a fluent interface is an implementation of an object oriented API that aims to provide for more readable code....

.

C#

class Person
{
private string _name;
private byte _age;

public Person SetName(string name)
{
_name = name;
return this;
}

public Person SetAge(byte age)
{
_age = age;
return this;
}

public Person Introduce
{
Console.WriteLine("Hello my name is {0} and I am {1} years old.", _name, _age);

return this;
}

}

//Usage:
static void Main
{
Person user = new Person;
// Output of this sequence will be: Hello my name is Peter and I am 21 years old.
user.SetName("Peter").SetAge(21).Introduce;
}

C++

class Person
{
const char* name;
int age;

public:

Person& SetName(const char* name)
{
Person::name = name;
return *this;
}

Person& SetAge(int age)
{
Person::age = age;
return *this;
}

void Introduce
{
std::cout << "Hello, my name is " << name << " and I am " << age << " years old." << std::endl;
}
};

//Usage:
int main
{
Person user;
// Output of this sequence will be: Hello my name is Peter and I am 21 years old.
user.SetName("Peter").SetAge(21).Introduce;
}

Java

class Person
{
private final String name;
private int age;

public Person setName(final String name) {
this.name = name;

return this;
}

public Person setAge(final int AGE) {
this.age = AGE;

return this;
}

public void introduce {
System.out.println("Hello, my name is " + name + " and I am " + age + " years old.");
}

// Usage:
public static void main(String[] args) {
Person person = new Person;
// Output of this sequence will be: Hello, my name is Peter and I am 21 years old.
person.setName("Peter").setAge(21).introduce;
}
}

Actionscript 3

The following is an example of a class with method chaining implemented in Actionscript

ActionScript

ActionScript is an object-oriented language originally developed by Macromedia Inc. . It is a dialect of ECMAScript , and is used primarily for the development of websites and software targeting the Adobe Flash Player platform, used on Web pages in the form of...

:

package examples.methodchaining
{
public class Person
{
private var _name:String;
private var _age:uint;

public function setName(value:String):Person
{
this._name = value;
return this;
}

public function setAge(value:String):Person
{
this._age = value;
return this;
}

public function introduce:void
{
trace("Hello, my name is " + _name + " and I am " + _age + " years old.");
}
}
}

Basic usage:

package
{
import examples.methodchaining

public class Main
{
public function Main:void
{
var person:Person = new Person;
// Output of this sequence will be: Hello, my name is Peter and I am 21 years old.
person.setName("Peter").setAge(21).introduce;
}
}
}

PHP

class Person
{
private $_name;
private $_age;

public function setName($name)
{
$this->_name = $name;
return $this;
}

public function setAge($age)
{
$this->_age = $age;
return $this;
}

public function introduce
{
printf(
'Hello my name is %s and I am %d years old.',
$this->_name,
$this->_age);
}
}

$user = new Person;

// Output of this sequence will be: Hello my name is Peter and I am 21 years old.
$user->setName('Peter')->setAge(21)->introduce;

External links

• Creating DSLs in Java using method chaining concept