In software development, many applications follow the same overall process but perform certain steps differently depending on the situation. In many cases, the workflow does not change, but the implementations will change depending on business needs.<\/p>\n\n\n\n
The online platform, for instance, could carry out the same steps for user authentication:<\/p>\n\n\n\n
But the verification step can vary for:<\/p>\n\n\n\n
Writing separate workflows repeatedly for each case creates duplicated code and makes applications difficult to maintain.<\/p>\n\n\n\n
That’s where the Template Method Design Pattern comes in handy.<\/p>\n\n\n\n
The Template Method Pattern allows developers to define the overall structure of an algorithm in a parent class while letting subclasses customize specific steps without changing the entire workflow.<\/p>\n\n\n\n
This pattern is commonly used in game development to make it easier to process and validate payments, to parse data from various sources, to integrate game functionality, and to generate reports.The pattern is used extensively in modern software development, particularly in game development, where it enhances code reusability, consistency, and maintainability.<\/p>\n\n\n\n
In this blog, we will see what is Template Method Design Pattern, its components, some practical examples, benefits and drawbacks of the design pattern, and finally we will see how to use it in code.<\/p>\n\n\n\n
Quick Answer:<\/strong><\/p>\n\n\n\n The Template Method Design Pattern is a behavioral design pattern that defines the overall structure of an algorithm in a parent class while allowing subclasses to customize specific steps. It helps reduce code duplication, maintain workflow consistency, and improve code reusability. The pattern is commonly used in authentication systems, report generation, data processing applications, and game development.<\/p>\n\n\n\n The Template Method Design Pattern is a behavioral design pattern that defines the skeleton of an algorithm inside a parent class while allowing subclasses to redefine certain steps of the algorithm.<\/p>\n\n\n\n The developers write down a common structure, and then customize the parts that differ for subclasses, instead of rewriting the complete workflow multiple times.<\/p>\n\n\n\n The overall process remains consistent while individual steps can behave differently.<\/p>\n\n\n\n For example, imagine a food delivery application.<\/p>\n\n\n\n Each order has a standard workflow of:<\/p>\n\n\n\n However, depending upon the restaurant or cuisine, the preparation step varies.<\/p>\n\n\n\n With the Template Method Pattern, developers can follow the same procedure but customize the necessary steps.<\/p>\n\n\n\n The main advantage of using this pattern is to prevent code duplication.<\/p>\n\n\n\n If the developers don’t use the Template Method Pattern, then the same workflow logic can be repeated in several different classes.<\/p>\n\n\n\n This results in issues like:<\/p>\n\n\n\n The Template Method Pattern solves this by:<\/p>\n\n\n\n This helps to develop the software architecture to be tidier and more organized.<\/p>\n\n\n\n One of the best examples of real-life applications is online payment processing.<\/p>\n\n\n\n Most payments tend to go through the following stages:<\/p>\n\n\n\n But the payment system varies when it comes to:<\/p>\n\n\n\n The overall work flow is the same, and some of the steps act in a different manner.<\/p>\n\n\n\n This is exactly what the Template Method Pattern is designed for.<\/p>\n\n\n\n The Abstract Class contains template method for overall workflow.<\/p>\n\n\n\n It usually:<\/p>\n\n\n\n The template method determines the flow of the algorithm.<\/p>\n\n\n\n abstract class DataParser {<\/p>\n\n\n\n \/\/ Template Method<\/p>\n\n\n\n public final void parseData() {<\/p>\n\n\n\n readData();<\/p>\n\n\n\n processData();<\/p>\n\n\n\n saveData();<\/p>\n\n\n\n }<\/p>\n\n\n\n abstract void readData();<\/p>\n\n\n\n abstract void processData();<\/p>\n\n\n\n public void saveData() {<\/p>\n\n\n\n System.out.println(“Saving processed data”);<\/p>\n\n\n\n }<\/p>\n\n\n\n }<\/p>\n\n\n\n In this class:<\/p>\n\n\n\n The parent class controls the structure while subclasses customize implementation details.<\/p>\n\n\n\n Concrete classes extend the abstract class and provide specific implementations for customizable steps.<\/p>\n\n\n\n Each subclass follows the same workflow but performs operations differently.<\/p>\n\n\n\n class CSVDataParser extends DataParser {<\/p>\n\n\n\n @Override<\/p>\n\n\n\n void readData() {<\/p>\n\n\n\n System.out.println(“Reading CSV data”);<\/p>\n\n\n\n }<\/p>\n\n\n\n @Override<\/p>\n\n\n\n void processData() {<\/p>\n\n\n\n System.out.println(“Processing CSV data”);<\/p>\n\n\n\n }<\/p>\n\n\n\n }<\/p>\n\n\n\n This class handles CSV file processing.<\/p>\n\n\n\n Although the workflow remains the same, the implementation differs from other parsers.<\/p>\n\n\n\n class JSONDataParser extends DataParser {<\/p>\n\n\n\n @Override<\/p>\n\n\n\n void readData() {<\/p>\n\n\n\n System.out.println(“Reading JSON data”);<\/p>\n\n\n\n }<\/p>\n\n\n\n @Override<\/p>\n\n\n\n void processData() {<\/p>\n\n\n\n System.out.println(“Processing JSON data”);<\/p>\n\n\n\n }<\/p>\n\n\n\n }<\/p>\n\n\n\n This class processes JSON data while still following the same template structure defined in the parent class.<\/p>\n\n\n\n The Client creates objects of concrete classes and executes the template method.<\/p>\n\n\n\n The client does not control individual steps directly.<\/p>\n\n\n\n Instead, it simply triggers the workflow.<\/p>\n\n\n\n Client Code<\/p>\n\n\n\n public class Main {<\/p>\n\n\n\n public static void main(String[] args) {<\/p>\n\n\n\n DataParser csvParser =<\/p>\n\n\n\n new CSVDataParser();<\/p>\n\n\n\n csvParser.parseData();<\/p>\n\n\n\n System.out.println();<\/p>\n\n\n\n DataParser jsonParser =<\/p>\n\n\n\n new JSONDataParser();<\/p>\n\n\n\n jsonParser.parseData();<\/p>\n\n\n\n }<\/p>\n\n\n\n }<\/p>\n\n\n\n Reading CSV data<\/p>\n\n\n\n Processing CSV data<\/p>\n\n\n\n Saving processed data<\/p>\n\n\n\n Reading JSON data<\/p>\n\n\n\n Processing JSON data<\/p>\n\n\n\n Saving processed data<\/p>\n\n\n\n Here\u2019s what happened in this example:<\/p>\n\n\n\n This methodology makes software applications to be scaled, maintained and updated over the time.<\/p>\n\n\n\n Most applications today tend to use the same authentication process:<\/p>\n\n\n\n The verification step can vary based on the authentication method used, however.<\/p>\n\n\n\n Examples include:<\/p>\n\n\n\n The Template Method Pattern enables a consistent login process while permitting the verification process to be changed.<\/p>\n\n\n\n Most enterprise applications create various kinds of reports and have a fairly common workflow.<\/p>\n\n\n\n For example:<\/p>\n\n\n\n The export step varies by report type, however.<\/p>\n\n\n\n Applications may generate:<\/p>\n\n\n\n The Template Method Pattern allows the reporting process to remain consistent, with the output format changing.<\/p>\n\n\n\n This pattern is commonly used when several file formats are processed, as the overall flow of processing is the same but some of the implementation changes.<\/p>\n\n\n\n For example:<\/p>\n\n\n\n However, the reading and processing logic varies in the following cases:<\/p>\n\n\n\n This approach prevents developers from rewriting the same workflow repeatedly.<\/p>\n\n\n\n The Template Method Pattern is typically used in game engines for character behavior systems.<\/p>\n\n\n\n The overall structure of the gameplay could be the same, e.g.:<\/p>\n\n\n\n But the changes in the implementation vary according to character type\/behavior of the AI.<\/p>\n\n\n\n For example:<\/p>\n\n\n\n The pattern enables developers to have the same workflow for the game, yet still be able to tailor the behaviors of their characters.<\/p>\n\n\n\n The Template Method Pattern offers several important benefits in software development.<\/p>\n\n\n\n While the Template Method Pattern has its advantages, it has a few disadvantages too.<\/p>\n\n\n\n The Template Method Pattern is frequently mistaken for the Strategy Pattern, as both patterns help to separate behaviors and enhance code organization.<\/p>\n\n\n\n But they are for different architectural issues.<\/p>\n\n\n\n This pattern works best when the overall process should remain unchanged.<\/p>\n\n\n\n This is preferable when there is a need for dynamic behavior changes in the applications.<\/p>\n\n\n\n The primary distinction is that the Template Method Pattern is about specifying the order of operations and the Strategy Pattern is about changing algorithms or behaviors.<\/p>\n\n\n\n You should consider using the Template Method Pattern when:<\/p>\n\n\n\n This pattern is particularly suitable for enterprise systems where workflows stay unchanged over time.<\/p>\n\n\n\n The following are the reasons that one should not use the Template Method Pattern:<\/p>\n\n\n\nWhat Is the Template Method Design Pattern?<\/strong><\/h2>\n\n\n\n
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Why Developers use Template Method Pattern<\/strong><\/h2>\n\n\n\n
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Real-World Example<\/strong><\/h2>\n\n\n\n
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Components of Template Method Design Pattern<\/strong><\/h2>\n\n\n\n
1. Abstract Class<\/strong><\/h3>\n\n\n\n
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Abstract Class Code<\/strong><\/h4>\n\n\n\n
Explanation<\/strong><\/h4>\n\n\n\n
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2. Concrete Classes<\/strong><\/h3>\n\n\n\n
CSV Data Parser<\/strong><\/h4>\n\n\n\n
Explanation<\/strong><\/h4>\n\n\n\n
JSON Data Parser<\/strong><\/h4>\n\n\n\n
Explanation<\/strong><\/h4>\n\n\n\n
3. Client<\/strong><\/h3>\n\n\n\n
Output<\/strong><\/h4>\n\n\n\n
Understanding the Workflow<\/strong><\/h2>\n\n\n\n
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Real-Life Software Applications<\/strong><\/h3>\n\n\n\n
Authentication Systems<\/strong><\/h3>\n\n\n\n
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Report Generation Systems<\/strong><\/h3>\n\n\n\n
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Data Processing Systems<\/strong><\/h3>\n\n\n\n
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Game Development<\/strong><\/h3>\n\n\n\n
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Advantages of Template Method Design Pattern<\/strong><\/h2>\n\n\n\n
Reduces Code Duplication<\/strong><\/h3>\n\n\n\n
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Improves Maintainability<\/strong><\/h3>\n\n\n\n
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Encourages Code Reusability<\/strong><\/h3>\n\n\n\n
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Maintains Workflow Consistency<\/strong><\/h3>\n\n\n\n
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Disadvantages of Template Method Design Pattern<\/strong><\/h2>\n\n\n\n
Tight Coupling via Inheritance<\/strong><\/h3>\n\n\n\n
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Difficult to Modify Core Workflow<\/strong><\/h3>\n\n\n\n
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Limited Runtime Flexibility<\/strong><\/h3>\n\n\n\n
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Template Method Pattern vs Strategy Pattern<\/strong><\/h2>\n\n\n\n
Template Method Pattern<\/strong><\/h3>\n\n\n\n
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Strategy Pattern<\/strong><\/h3>\n\n\n\n
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When Should You Use the Template Method Pattern?<\/strong><\/h2>\n\n\n\n
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When Should You Avoid It?<\/strong><\/h2>\n\n\n\n