SOLID & Design Patterns Interview Question #54

What is the Flyweight Pattern?

Advanced Patterns, CQRS & Domain-Driven Design Fundamentals Mid-Level Intermediate

Quick Interview Answer

The Flyweight Pattern reduces memory usage by sharing common immutable state among many logical objects instead of duplicating that state in every instance. Instance-specific state is kept separately.

Detailed Explanation

It is most useful when an application creates a very large number of similar objects and profiling shows duplicated state is a meaningful memory cost. It adds complexity and should not be introduced without a real need.

Code Example

public sealed record TextStyle(
    string FontFamily,
    int FontSize,
    bool Bold);

// Many text runs can share the same
// immutable TextStyle instance.