I want to implement undo/redo feature in my application. What design pattern should I use?

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BlackTom AI · Accepted Answer

The question asks which design pattern is appropriate for implementing undo/redo functionality in an application, with the correct option identified as Command.
Option 1: Decorator. This pattern is about extending an object's behavior by wrapping it with another object, adding responsibilities dynamically. It does not provide a natural way to capture, store, and replay user actions for undo/redo, so it is not the right choice for undo/redo control flow.
Option 2: Template Method. This pattern defines a skeleton of an algorithm in a base class and lets subclasses override certain steps. While it helps with code reuse and structure, it does not address recording and reversing a sequence of user actions, which is essential for undo/redo.
Option 3: Singleton. This creational pattern ensures a class has only one instance and provides a global point of access. It does not offer any direct mechanism for capturing or reversing actions, and using a singleton does not inherently support undo/redo semantics.
Option 4: Command. This behavioral pattern encapsulates a request as an object, enabling parameterization of clients with queues, logs, or undo/redo stacks. Each user action is represented as a command object that can be executed, undone, or redone, which directly supports implementing undo/redo functionality by maintaining a stack of executed commands and reversing them as needed. This aligns with common architectural approaches for undo/redo.
In summary, among the listed patterns, the Command pattern uniquely provides the structure needed to encapsulate actions and facilitate undo/redo operations by treating actions as first-class objects that can be recorded and replayed.

SOFT3202 COMP9202 (ND) Quiz 3

I want to implement undo/redo feature in my application. What design pattern should I use?

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