我正在尝试使用Java枚举,但代码没有编译。在整个代码中,我都会得到以下错误。
类、接口或枚举期望的
误差
vm@vm:~/Documents/Oops/DesignPatterns/CommandPattern$ javac Kitchen.java
Kitchen.java:1: '.' expected
import HomeApplianceAction;
^
Kitchen.java:1: ';' expected
import HomeApplianceAction;
^
Kitchen.java:3: class, interface, or enum expected
class Kitchen{
^
Kitchen.java:5: class, interface, or enum expected
private Door_Enum kitchen_door;
^
Kitchen.java:6: class, interface, or enum expected
private Fan_Enum exhaust_fan;
^
Kitchen.java:8: class, interface, or enum expected
Kitchen(){
^
Kitchen.java:10: class, interface, or enum expected
this.kitchen_door = Door_Enum.DOOR_SHUT;
^
Kitchen.java:11: class, interface, or enum expected
this.exhaust_fan = Fan_Enum.FAN_SWITCHED_OFF;
^
Kitchen.java:12: class, interface, or enum expected
}
^
Kitchen.java:14: class, interface, or enum expected
public void setKitchenLights(Light_Enum kitchen_light){如何修复此错误消息?
下面是代码片段:
public interface HomeApplianceAction{
}
enum Light_Enum implements HomeApplianceAction{
LIGHTS_ON,
LIGHTS_OFF,
LIGHTS_DIM;
}
enum Door_Enum implements HomeApplianceAction{
DOOR_OPEN,
DOOR_SHUT;
}
enum TV_Enum implements HomeApplianceAction{
TV_POWERED_ON,
TV_POWERED_OFF,
TV_STANDBY;
}
enum Computer_Enum implements HomeApplianceAction{
COMP_POWERED_ON,
COMP_POWERED_OFF,
COMP_STANDBY,
COMP_SLEEP,
COMP_HIBERNATE;
}
enum Fan_ENUM implements HomeApplianceAction{
FAN_SWITCHED_OFF,
FAN_LOW,
FAN_MEDIUM,
FAN_HIGH;
}上述代码被放置在HomeApplianceAction.java文件中,并正在成功编译。现在我想在Kitchen.java文件中使用这些枚举,如下所示:
import HomeApplianceAction;
class Kitchen{
private Light_Enum kitchen_light;
private Door_Enum kitchen_door;
private Fan_Enum exhaust_fan;
Kitchen(){
this.kitchen_light = Light_Enum.LIGHTS_OFF;
this.kitchen_door = Door_Enum.DOOR_SHUT;
this.exhaust_fan = Fan_Enum.FAN_SWITCHED_OFF;
}
public void setKitchenLights(Light_Enum kitchen_light){
this.kitchen_light = kitchen_light;
}
public void setKitchenDoor(Door_Enum kitchen_door){
this.kitchen_door = kitchen_door;
}
public void setKitchenExhaustFan(Fan_Enum exhaust_fan){
this.exhaust_fan = exhaust_fan;
}
public void execute(HomeApplianceAction action){
if(action instanceof Light_Enum){
setKitchenLights(action);
}
else if(action instanceof Door_Enum){
setKitchenDoor(action);
}
else if(action instanceof Fan_Enum){
setKitchenExhaustFan(action);
}
else{
System.out.println("Invalid action performed on Kitchen Appliance");
}
}
}发布于 2016-01-18 19:51:10
您有一个文件,其中包含多个枚举和一个公共接口。文件".java“称为编译单元。每个编译单元只能有一个公共类、接口或枚举。
您可以创建每个枚举的先锋编译单元,也可以在接口中实现枚举并访问它,如下所示:
HomeApplianceAction.Computer_Enum.COMP_HIBERNATE否则,只能从接口中看到枚举。
发布于 2016-01-18 19:57:20
在同一个文件中有几个类、接口或枚举,这不是最佳实践。
把它们分成不同的档案(如:
在HomeApplianceAction.java中:
public interface HomeApplianceAction{
}在LightEnum.java中
public enum LightEnum implements HomeApplianceAction{
LIGHTS_ON,
LIGHTS_OFF,
LIGHTS_DIM;
}请注意,我编写的是LightEnum,而不是遵循java代码命名约定的Light_Enum。还请注意公共修饰符,它允许您在其他包中的类中使用此枚举。
您应该考虑为这些类和枚举声明包,并且可能需要添加导入语句才能从其他类中使用它们,如下所示:
import LightEnum;或
import <yourpackage>.LightEnum;https://stackoverflow.com/questions/34862737
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