Intermediate LevelSoftware Engineering Principles
What is the Template Method Pattern and how does it define algorithm skeletons?
❓ Interview Prompt: Explain the Template Method Behavioral Pattern, defining algorithm step invariant skeletons in abstract base classes, and subclass hooks.
The Template Method Pattern defines the skeleton of an algorithm in a method of an abstract base class, deferring some specific steps to subclasses without modifying the overall algorithm structure:
Invariant vs Variant Steps:
•
Invariant Skeleton: Base class enforces execution order ('step1() -> step2() -> step3()').
•
Variant Hooks: Subclasses override specific step implementations.
Code Implementation Example
typescript
abstract class DataMiner {
// Template Method enforcing execution skeleton!
mine() {
this.openFile();
this.parseData();
this.closeFile();
}
abstract parseData(): void; // Deferred to subclasses
private openFile() { console.log('File Opened'); }
private closeFile() { console.log('File Closed'); }
}💡Defining algorithm execution skeletons with Template Method pattern.
🎯 Interview Key Takeaway
Use the Template Method pattern to fix algorithm execution skeletons in base classes while letting subclasses override specific steps.
#Template Method#Design Patterns#Behavioral#Intermediate
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