Behavioural Design Patterns: Strategy, Observer, Command & More | Low Level Design

Unlock the secrets of behavioural design patterns in software engineering! This comprehensive video guides learners and interview aspirants through all major behavioural patterns, equipping you with real-world examples, implementation insights, and interview-ready answers.

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What Are Behavioural Design Patterns?
Behavioural patterns focus on how objects communicate and interact, clarifying responsibilities, organizing complex workflows, and improving code flexibility. Mastering these patterns helps you write modular, maintainable, and scalable applications ready for production and interviews.

Patterns Covered in This Video
Chain of Responsibility: Allows a request to pass through a chain of handlers until one processes it. Common in event processing and middleware pipelines, like logging or authorization workflows. ([29-Behavioural-Chain-of-Responsibility-Pattern.md])

Command Pattern: Encapsulates requests as objects, enabling parameterization, queuing, undo, and logging of operations. Essential for remote controls, transactional systems, and UI actions. ([30-Behavioural-Command-Pattern.md])

Iterator Pattern: Provides a way to traverse elements of a collection without exposing its underlying representation. Used in collections, tree structures, and custom data aggregations. ([31-Behavioural-Iterator-Pattern.md])

Mediator Pattern: Centralizes complex communications between objects, reducing direct dependencies and simplifying code. Common in chat systems, air traffic control, and UI frameworks. ([32-Behavioural-Mediator-Pattern.md])

Memento Pattern: Captures and restores an object's state, enabling undo/redo in editors, games, and workflows. ([33-Behavioural-Memento-Pattern.md])

Observer Pattern: Defines a subscription mechanism for notifying multiple objects of events. Ideal for event-driven architectures, GUIs, and notification services. ([34-Behavioural-Observer-Pattern.md])

State Pattern: Allows an object to change its behavior when its internal state changes, without modifying the object’s code. Used for state machines, UI interaction models, and lifecycle management. ([35-Behavioural-State-Pattern.md])

Strategy Pattern: Enables selecting algorithms at runtime, promoting flexibility and code reuse. Seen in sorting operations, payment gateways, and routing logic. ([36-Behavioural-Strategy-Pattern.md])

Template Method Pattern: Defines the skeleton of an algorithm, letting subclasses fill in specific steps. Streamlines repetitive logic with customizable operations. ([37-Behavioural-Template-Method-Pattern.md])

Visitor Pattern: Separates algorithms from object structures, allowing new operations without altering classes. Useful for AST traversal, report generation, and compiler implementations. ([38-Behavioural-Visitor-Pattern.md])

Why Are These Patterns Important?
Simplify complex workflows for clean, scalable code

Decouple object interactions for better maintainability

Organize event handling, data traversal, and state management

Empower production systems and interview answers with formalized approaches

Who Should Watch?
Software engineers preparing for system design or coding interviews

CS students and professionals learning modern architecture

Backend and frontend developers handling events, states, or complex object interactions

Keywords for Ranking
behavioural design patterns, strategy pattern, observer pattern, command pattern, mediator pattern, memento pattern, chain of responsibility, iterator pattern, state pattern, template method pattern, visitor pattern, interview preparation, OOP patterns, software architecture, object communication, event-driven architecture, modular design, code maintainability

Effective Hashtags
#BehaviouralPatterns

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#MediatorPattern

#MementoPattern

#StatePattern

#TemplateMethodPattern

#VisitorPattern

#SoftwareArchitecture

#InterviewPrep

#OOP

#EventDriven

#Coding

Ready to master behavioural patterns and ace interviews? Watch now!