java - 什么模式与策略模式一起使用可以避免具体策略中的重复代码？

Question

我对设计模式比较陌生，在下面的示例中我使用了我认为是策略模式的东西。但是，我在一些，而不是全部具体策略中重复自己，想知道是否有办法避免这种情况？在做一些独特的事情之前，请注意 ACommand 和 CCommand 如何具有相同的代码。

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;
    }

    //...
}

命令

    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
        }
}

B命令

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

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

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 之间公共(public)基类的基础。基类中的模板方法将保存公共(public)代码，然后调用一个 (abstract) 方法来 doSomethingUnique()。