java - 摆脱枚举中的代码重复

Question

我有一个接口(interface)，我想用枚举来实现它，但是有些方法是相同的，这会导致代码重复。我会使用抽象类而不是接口(interface)，但 java 不允许枚举扩展任何东西。有没有解决的办法？我包含了一些代码来帮助理解问题。

public interface CommandI {
  boolean isCommand(String command);
  void execute(Drawer drawer, Creature creature);
  String getDescription();
}



public enum Command2 implements CommandI {
  FORWARD{
    private String description = "qwersadd";
    private String[] aliases = {"fd", "forward"};
    @Override
    public boolean isCommand(String command) {
        for (String s: aliases){
        if (s.equals(command)){
          return true;
        }
      }
      return false;
    }
    @Override
    public void execute(Drawer drawer, Creature creature) {
      throw new UnsupportedOperationException("Not supported yet.");
    }
    @Override
    public String getDescription() {
      return description;
    }
  },
  PENUP{
    private String description = "vcvzxcvz";
    private String[] aliases = {"pu", "penup"};
    @Override
    public boolean isCommand(String command) {
        for (String s: aliases){
        if (s.equals(command)){
          return true;
        }
      }
      return false;
    }
    @Override
    public void execute(Drawer drawer, Creature creature) {
      throw new UnsupportedOperationException("Not supported yet.");
    }
    @Override
    public String getDescription() {
      return description;
    }
  }

}

如您所见，只有执行方法不同。

Answer 1

我不确定您是否真的了解枚举的用途。以下是您应该实现 Command2 的方式:

public enum Command2 implements CommandI {

    FORWARD("qwersadd", new String[] { "fd", "forward" }),
    PENUP("vcvzxcvz", new String[] { "pu", "penup" });

    private final String description;
    private final String[] aliases;

    private Command2(String description, String[] aliases) {
        this.description = description;
        this.aliases = aliases;
    }

    @Override
    public boolean isCommand(String command) {
        for (String s : aliases) {
            if (s.equals(command)) {
                return true;
            }
        }
        return false;
    }

    @Override
    public void execute(Drawer drawer, Creature creature) {
        throw new UnsupportedOperationException("Not supported yet.");
    }

    @Override
    public String getDescription() {
        return description;
    }

}

例如，当你想要实现 FORWARD 的 execute 主体时，只需(覆盖)覆盖它，如下所示:

FORWARD("qwersadd", new String[] { "fd", "forward" }) {
    @Override
    public void execute(Drawer drawer, Creature creature) {
        // specific execute body for FORWARD
    }
}