vivi-exercises/bank/src/main/java/de/vivi/Command.java

package de.vivi;

import de.vivi.bank.Bank;

import java.util.HashMap;
import java.util.Map;
import java.util.function.BiConsumer;

public class Command {

    private static final Map<String, Command> COMMANDS = new HashMap<String, Command>() {{
        put("create", new Command(1, (bank, args) -> bank.create(args[1])));
        put("info", new Command(1, (bank, args) -> bank.info(Integer.parseInt(args[1]))));
        put("add", new Command(1, (bank, args) -> bank.add(Integer.parseInt(args[1]), Integer.parseInt(args[2]))));
        put("remove", new Command(1, (bank, args) -> bank.remove(Integer.parseInt(args[1]), Integer.parseInt(args[2]))));
        put("transfer", new Command(1, (bank, args) -> bank.transfer(Integer.parseInt(args[1]), Integer.parseInt(args[2]), Integer.parseInt(args[3]))));
        put("transactions", new Command(1, (bank, args) -> bank.transactions(Integer.parseInt(args[1]))));
    }};

    private final int args;

    private final BiConsumer<Bank, String[]> consumer;

    private Command(int args, BiConsumer<Bank, String[]> consumer) {
        this.args = args;
        this.consumer = consumer;
    }

    public static void exec(Bank bank, String[] args) {
        if (args.length > 0) {
            Command command = COMMANDS.get(args[0]);

            if (command == null) {
                System.out.println("Command not found");
                return;
            }

            if (command.args != args.length) {
                System.out.println("Invalid argument count");
                return;
            }

            try {
                command.consumer.accept(bank, args);
            } catch (NumberFormatException e) {
                System.out.println("Invalid argument");
            }
        }
    }
}