README.md

Command Pattern

What is the Command Pattern?

The Command Pattern is a behavioral design pattern that turns a request into a stand-alone object containing all information about the request. This transformation lets you parameterize methods with different requests, delay or queue a request's execution, and support undoable operations.

Implementation in This Project

This example demonstrates the Command pattern by implementing stock trading orders:

• Order: Command interface.
• BuyStock, SellStock: Concrete commands.
• Stock: Receiver that performs the actual operations.
• Broker: Invoker that takes and executes commands.

Class Diagram

flowchart TD
    A["App.java"] --> B["Broker (Invoker)"]
    B --> C["Order (interface)"]
    C --> D["BuyStock"]
    C --> E["SellStock"]
    D --> F["Stock (Receiver)"]
    E --> F

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Example Usage

Stock abcStock = new Stock();

BuyStock buyStockOrder = new BuyStock(abcStock);
SellStock sellStockOrder = new SellStock(abcStock);

Broker broker = new Broker();
broker.takeOrder(buyStockOrder);
broker.takeOrder(sellStockOrder);

broker.placeOrders();

When to Use

• When you want to parameterize objects with operations.
• When you want to queue operations, schedule their execution, or execute them remotely.