为什么切换会导致无法解决错误？

发布于 2024-12-21 00:58:06 字数 1172 浏览 2 评论 0原文

我在包 A 中有一个枚举，它有一个静态转换器方法，我用它来为另一个包 B 中的一组特定类获取适当的枚举类型（另一个包中的每个类都有一个相应的枚举）。

现在，从第三个包 C（它不导入包 A，但导入包 B）中，我尝试打开枚举。

现在，当我使用 switch 检查枚举时，它会抱怨：

无法解析类型 nz.ac.waikato.jstar.jStar.OrderOperator。它是从必需的 .class 间接引用的文件

但是，当我使用 if 语句时却没有。

谁能解释一下为什么 switch 会导致错误，而 if 却不会？

代码：

//Doesn't work
switch (connection.getType()) {
    case LESS_THAN:
        break;
    case LESS_THAN_EQUALS:
        break;
    default:
        break;
}

//Works Fine
if(connection.getType() == OrderingConnectionType.LESS_THAN) {
    return -1;
} else if(connection.getType() == OrderingConnectionType.LESS_THAN_EQUALS) {
    return 2;
}

引用bundle A的Enum静态方法（OrderOperator来自Bundle A）：

public static OrderingConnectionType getType(Class<? extends OrderOperator> operatorType) {
    for (OrderingConnectionType type : OrderingConnectionType.values()) {
        if(type.operatorType.isAssignableFrom(operatorType)) return type;
    }
    throw new IllegalArgumentException("Unknown Operator type: " + operatorType);
}

原文

I have an enum in package A which has a static converter method, which I use to get the appropriate enum type for a particular set of classes in another package B (each class in the other package has a corresponding enum).

Now, from a third package C, which does not import package A, but does import package B I'm trying to switch on the enum.

Now, when I use a switch to check the enum, it complains:

The type nz.ac.waikato.jstar.jStar.OrderOperator cannot be resolved. It is indirectly referenced from required .class
files

However, when I use an if statement it doesn't.

Can anyone shed light as to why the switch causes the error but the if doesn't?

Code:

//Doesn't work
switch (connection.getType()) {
    case LESS_THAN:
        break;
    case LESS_THAN_EQUALS:
        break;
    default:
        break;
}

//Works Fine
if(connection.getType() == OrderingConnectionType.LESS_THAN) {
    return -1;
} else if(connection.getType() == OrderingConnectionType.LESS_THAN_EQUALS) {
    return 2;
}

Enum's static method that refers to bundle A (OrderOperator is from Bundle A):

public static OrderingConnectionType getType(Class<? extends OrderOperator> operatorType) {
    for (OrderingConnectionType type : OrderingConnectionType.values()) {
        if(type.operatorType.isAssignableFrom(operatorType)) return type;
    }
    throw new IllegalArgumentException("Unknown Operator type: " + operatorType);
}

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何其悲哀 2024-12-28 00:58:06

添加 OrderingConnectionType。为开关的情况添加前缀，它将起作用。

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走走停停 2024-12-28 00:58:06

您应该给出精确的枚举类型进行比较。您是在 if 语句 中执行此操作，而不是在 switch 中执行此操作。

switch (connection.getType()) {
    case OrderingConnectionType.LESS_THAN:
        break;
    case OrderingConnectionType.LESS_THAN_EQUALS:
        break;
    default:
        break;
}

you should give exact enum type to compare.. you are doing this in if statement but not in switch.

switch (connection.getType()) {
    case OrderingConnectionType.LESS_THAN:
        break;
    case OrderingConnectionType.LESS_THAN_EQUALS:
        break;
    default:
        break;
}

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