Open-Closed Principle - Revision history

Admin at 07:54, 3 May 2020

2020-05-03T07:54:43Z

Admin at 12:39, 15 August 2019

2019-08-15T12:39:25Z

Admin at 12:37, 15 August 2019

2019-08-15T12:37:44Z

Admin at 12:30, 15 August 2019

2019-08-15T12:30:39Z

Admin: Created page with "The '''open/closed principle''' states "software entities should be open for extension, but closed for modification". Open for extension means that we should be able to add n..."

2019-08-15T11:30:26Z

Created page with "The '''open/closed principle''' states "software entities should be open for extension, but closed for modification". Open for extension means that we should be able to add n..."

New page

The '''open/closed principle''' states "software entities should be open for extension, but closed for modification".

Open for extension means that we should be able to add new features or components to the application without breaking existing code.

Closed for modification means that we should not introduce breaking changes to existing functionality.

← Older revision		Revision as of 07:54, 3 May 2020
Line 58:		Line 58:
	}		}

−	By using '''Inheritance''' and '''[[Polymorphism]]''', it is now much easier to create extended behavior to the calculate area of different shapes. The cool thing is, that if we want to add new shapes then we can change/add the code without affecting any of these underlying pieces of behavior.	+	By using '''[[Inheritance]]''' and '''[[Polymorphism]]''', it is now much easier to create extended behavior to the calculate area of different shapes. The cool thing is, that if we want to add new shapes then we can change/add the code without affecting any of these underlying pieces of behavior.

← Older revision		Revision as of 12:39, 15 August 2019
Line 58:		Line 58:
	}		}

−	By using '''Inheritance''' and '''Polymorphism''', it is now much easier to create extended behavior to the calculate area of different shapes. The cool thing is, that if we want to add new shapes then we can change/add the code without affecting any of these underlying pieces of behavior.	+	By using '''Inheritance''' and '''[[Polymorphism]]''', it is now much easier to create extended behavior to the calculate area of different shapes. The cool thing is, that if we want to add new shapes then we can change/add the code without affecting any of these underlying pieces of behavior.

@@ Line 20: / Line 20: @@
              Console.WriteLine("Area of circle : " + ((3.14) * radius * radius).ToString());
+         }
          public void calculateRectangleArea(double length, double width)
+         {
              Console.WriteLine("Area of rectangle : " + (length * width).ToString());
+         }
+     }
@@ Line 41: / Line 39: @@
+         }
          public abstract double calculateArea();
+     }
      class Square : Shapes
@@ Line 60: / Line 57: @@
+         }
+     }

← Older revision		Revision as of 12:30, 15 August 2019
Line 4:		Line 4:

	Closed for modification means that we should not introduce breaking changes to existing functionality.		Closed for modification means that we should not introduce breaking changes to existing functionality.
		+
		+	== Open-Closed Principle Example ==
		+	Let’s take a look at an example in C#. Even if you are not a C# developer, with some OOP experience you will be able to follow along easily.
		+
		+	Let’s take a look how to write the below piece of code is violating this principle.
		+
		+	class Shapes
		+	{
		+	public Shapes()
		+	{
		+	Console.WriteLine("Class : Shapes");
		+	}
		+	public void calculateCircleArea(double radius)
		+	{
		+	Console.WriteLine("Area of circle : " + ((3.14) * radius * radius).ToString());
		+	}
		+
		+	public void calculateRectangleArea(double length, double width)
		+	{
		+	Console.WriteLine("Area of rectangle : " + (length * width).ToString());
		+	}
		+
		+	}
		+
		+	You will notice how we are calculating area of different shapes. If we want to add a new shape then we need to update this class by adding a new method.
		+
		+	This violates the Open-Closed Principle.
		+
		+	Let’s correct it.
		+
		+	abstract class Shapes
		+	{
		+	public Shapes()
		+	{
		+	Console.WriteLine("Class : Shapes");
		+	}
		+	public abstract double calculateArea();
		+
		+	}
		+	class Square : Shapes
		+	{
		+	public double length { get; set; }
		+	public double width { get; set; }
		+	public override double calculateArea()
		+	{
		+	return (length * width);
		+	}
		+	}
		+	class Circle : Shapes
		+	{
		+	public double radius { get; set; }
		+	public override double calculateArea()
		+	{
		+	return ((3.14) * radius * radius);
		+	}
		+	}