Question

我对设计模式相对较新，在下面的例子中，我使用的是我认为的策略模式。但是，我在一些，而不是全部，具体策略中重复自己，并想知道有没有办法避免这种情况？注意ACommand和CCommand在做一些独特的事情之前是如何拥有相同的代码的。

public interface Command 
{
    public boolean execute(CommandSender sender, String[] args);
    public String getName();
    //...
}

public abstract class PlayerCommand implements Command 
{
    protected BukkitPlugin plugin = BukkitPlugin.getInstance();

    private String name;
    //...

    public PlayerCommand(String name) 
    {
        this.name = name;
    }

    public String getName() 
    {
        return this.name;
    }

    //...
}

ACommand

    public class ACommand extends PlayerCommand
    {
        public ACommand()
        {
            super("A");
        }

        public boolean execute(CommandSender sender, String[] args)
        {
            Player player = (Player) sender;
            PlayerInventory inventory = player.getInventory();
            ItemStack itemInHand = inventory.getItemInHand();

            if(itemInHand.getType() != Material.COMPASS)
            {
                sender.sendMessage("You must be holding a phone to use this command");
                return true;
            }

            int id = itemInHand.getDurability();

            MobilePhoneManager phoneManager = plugin.getMobilePhoneManager();       
            boolean isMobilePhone = phoneManager.isMobilePhone(id);

            if(!isMobilePhone)
            {
                sender.sendMessage("You must be holding a mobile phone to use this command");
                return true;
            }

            //DO SOMETHING UNIQUE HERE
        }
}

BCommand

public class BCommand extends PlayerCommand
        {
            public BCommand()
            {
                super("B");
            }

            public boolean execute(CommandSender sender, String[] args)
            {
                //SOMETHING ELSE
            }
    }

的CCommand

    public class CCommand extends PlayerCommand
    {
        public CCommand()
        {
            super("C");
        }

        public boolean execute(CommandSender sender, String[] args)
        {
            Player player = (Player) sender;
            PlayerInventory inventory = player.getInventory();
            ItemStack itemInHand = inventory.getItemInHand();

            if(itemInHand.getType() != Material.COMPASS)
            {
                sender.sendMessage("You must be holding a phone to use this command");
                return true;
            }

            int id = itemInHand.getDurability();

            MobilePhoneManager phoneManager = plugin.getMobilePhoneManager();       
            boolean isMobilePhone = phoneManager.isMobilePhone(id);

            if(!isMobilePhone)
            {
                sender.sendMessage("You must be holding a mobile phone to use this command");
                return true;
            }

            //DO SOMETHING UNIQUE HERE
        }
}

Answer 1

您可以使用template pattern作为ACommand和CCommand之间的公共基类的基础。基类中的模板方法将保存公共代码，然后调用（abstract）方法到doSomethingUnique()。

Answer 2

安德烈在所有方面都是正确的。您正在使用Command模式，您只需稍微调整一下您的接口，以包含一些关于命令当前是否处于可执行状态的概念

bool canExecute();
boll canExecute(args)

您通常看不到execute方法返回任何内容。

HTH，
Berryl

使用策略模式的模式可以避免混凝土策略中的重复代码？

2 个答案: