How Can the Command Pattern Improve Code Maintainability and Simplify Command Handling in Java?

Reducing Long If-Statement Chains in Java

Question:

When managing incoming text commands in an embedded system, a long chain of if-else statements was used to handle each command. As the number of commands grew, this approach became unmanageable and difficult to debug.

Solution:

To address this issue, the Command pattern was employed. This pattern involves creating a separate class for each command, which implements a specific interface containing the exec() method. Then, a map is created to match command strings to their corresponding classes.

Java Implementation:

<code class="java">public interface Command {
    void exec();
}

public class CommandA implements Command {
    @Override
    public void exec() {
        // ...
    }
}

// Other command classes

Map<String, Command> commandMap = new HashMap<>();

// Populate the map
commandMap.put("A", new CommandA());
commandMap.put("B", new CommandB());

// Execute the command
commandMap.get(value).exec();</code>

Benefits:

• Separates logic for each command into a designated class, making code more modular and maintainable.
• Simplifies the main processing loop by replacing the if-else chain with a single map lookup.
• Allows for the addition of new commands or special commands (e.g., UnknownCommand) without modifying the main processing logic.

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