Template method design pattern java examples

The Template Pattern The Template Method pattern is known as a behavioural pattern,as it's used to manage algorithms, relationships and responsibilities between objects. Thedefinition of Template Method provided in the original Gang of Four book on DesignPatterns states: Defines the skeleton of an algorithm in a method, deferring some steps to subclasses. In practice, the Template Method pattern is quite simple - let's look at a class diagram representation The AbstractClass contains the templateMethod , which should be made final so that it cannot be overridden.

When broken down, there are four different types of methods used in the parent class: Concrete methods Standard complete methods that are useful to the subclasses. These methods are usually utiity methods. Abstract methods Methods containing no implementation that must be implemented in subclasses.

Hook methods Methods containing a default implementation that may be overidden in some classes. Hook methods are intended to be overridden, concrete methods are not. Template methods A method that calls any of the methods listed above in order to describe the algorithm without needing to implement the details.

The Template Method pattern is used when When behaviour of an algorithm can vary, you let subclasses implement the behaviour through overriding You want to avoid code duplication, implementing variations of the algorithm in subclasses You want to control the point that subclassing is allowed.

Next Up We're going to look at the Prototype pattern later this week. Opinions expressed by DZone contributors are their own. You could also make the method final.

In some cases, you might want to let it be overriden. Stick to the text books, and stop copying stuff from Joe! Your email address will not be published. Next Visitor Design Pattern in Java. Pankaj I love Open Source technologies and writing about my experience about them is my passion.

Follow Author. Comments Nakul says:. September 2, at am. Mohsin says:. July 12, at pm. Sharath says:. June 16, at am. Raheem says:. Step 1: Create CaffeineBeverage class ,which defines skeleton for the algorithm.

Step 2 : Create a Coffee class , which extends abstract CaffeineBeverage class and implements abstract methods. Step 3 : Create a Tea class which extends abstract CaffeineBeverage class and implements abstract methods.

Step 4 : With a hook, we can override a method or not, It's our choice , If we don't then abstract class provides default implementation. Step 5 : Let's override the hook method and provide the own implementation. Step 6 : Test the above implementation. Output :. Template Method lets subclasses redefine certain steps of an algorithm without changing the algorithm's structure. Explanation Real-world example The general steps in stealing an item are the same.