Design Patterns Simplified - Part 9 (Adapter)

Before starting, I would request that you visit the previous articles on Design Patterns series:

• Design Patterns Simplified: Part 1
• Design Patterns Simplified - Part 2 (Singleton)
• Design Patterns Simplified - Part 3 (Simple Factory)
• Design Patterns Simplified - Part 4 (Abstract Factory)
• Design Patterns Simplified - Part 5 (Factory Method)
• Design Patterns Simplified - Part 6 (Prototype)
• Design Patterns Simplified - Part 7 (Builder)
• Design Patterns Simplified - Part 8 (Facade)

I am here to continue the discussion around Design Patterns. Today we will go through one of the structural design patterns called Adapter. Before talking about its implementation let’s begin with defining it.

As per GOF guys, Adapter pattern is defined as the following.

“Convert the interface of a class into another interface clients expect. Adapter lets classes work together that couldn't otherwise because of incompatible interfaces.”

Well! Let’s understand what they mean.

It means that Adapter pattern links two incompatible interfaces which have the same functionality but their methods are called a little differently. Sometimes it is also called a wrapper.

How Adapter pattern works

Adapter pattern can be used to integrate with other external components that might have the same functionality we need but their functions are not called quite the same way. Assume we have an Employee class with a function defined as PrintEmployee and we work with an external contract employee provider that has an EmployeeDetail class with a function as ListEmployee.

Here we can create an adapter class to wrap the external EmployeeDetailclass so that a call to PrintEmployee() of the adapter is delegated to ListEmployee() of the external class.

Let’s understand this by a simple example.