Design Pattern:: Template Method

Design Pattern::Template Method

http://jyaasa.comCopyright 2016. Jyaasa Technologies.

Hello ! I am Neha Suwal


Associate Software Engineer

Jyaasa Technologies


Gang of Four Definition:

“Define a skeleton of an algorithm in an operation, deferring some steps to subclasses. It lets subclasses redefine certain steps of an algorithm without changing its subclasses.”

Template Method


That means, instead of having a huge if/switch/ case statement

somewhere to control what happens, Template Method lets object itself

determine what happens by using a method that all siblings inherit but

implement in their own way.

What does that mean?


Structure


● `template_method` calls `step_one` method, `step_two` method and

`step_three` method

● `step_two` is a hook method. I.e It is declared in base class and

then defined in subclasses


Where to use?● A class has more than one method that each contains an

if/switch/case statement with 3 or more possibilities.

● A class which has an if/switch/case statement that can have new

possibilities as conditions in the future.


ExampleOUTPUT:

MOO MOOOINK OINKQUACK QUACK


ExampleOUTPUT:

MOO MOO

uninitialized constant Animal::NotImplementedException (NameError)


● No code duplication

● Since uses inheritance code is reused

● Lets subclasses decide how to implement steps in an algorithm.

Advantage


● Understanding the sequence of flow

● Problem in maintenance

Disadvantage

Thank you!

Queries? Lets Discuss!!

https://np.linkedin.com/in/nsuwalhttps://github.com/ne-ha

http://jyaasa.comCopyright 2015. Jyaasa Technologies. Copyright 2016. Jyaasa Technologies. http://jyaasa.com

Design Pattern:: Template Method

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