使用枚举序数是一种好习惯吗? [英] Is it good practice to use ordinal of enum?

问题描述

我有一个枚举:

public enum Persons {

    CHILD,
    PARENT,
    GRANDPARENT;

}

使用 ordinal() 方法检查枚举成员之间的层次结构"有什么问题吗?我的意思是 - 除了冗长之外，使用它是否有任何缺点，因为将来有人可能会意外更改顺序.

Is there any problem with using ordinal() method to check "hierarchy" between enum members? I mean - is there any disadvantages when using it excluding verbosity, when somebody can change accidentally order in future.

或者做这样的事情更好:

Or is it better to do something like that:

public enum Persons {

    CHILD(0),
    PARENT(1),
    GRANDPARENT(2);

    private Integer hierarchy;

    private Persons(final Integer hierarchy) {
        this.hierarchy = hierarchy;
    }

    public Integer getHierarchy() {
        return hierarchy;
    }

}

推荐答案

TLDR:不，你不应该！

如果你在Enum.java中参考ordinal方法的javadoc:

If you refer to the javadoc for ordinal method in Enum.java:

大多数程序员不会使用这种方法.它是设计用于复杂的基于枚举的数据结构，例如如 java.util.EnumSet 和 java.util.EnumMap.

Most programmers will have no use for this method. It is designed for use by sophisticated enum-based data structures, such as java.util.EnumSet and java.util.EnumMap.

首先 - 阅读手册(在本例中为 javadoc).

Firstly - read the manual (javadoc in this case).

其次 - 不要编写脆弱的代码.枚举值将来可能会发生变化，您的第二个代码示例清晰和可维护.

Secondly - don't write brittle code. The enum values may change in future and your second code example is much more clear and maintainable.

如果在 PARENT 和 GRANDPARENT 之间插入一个新的枚举值，你绝对不希望为未来制造问题.

You definitely don't want to create problems for the future if a new enum value is (say) inserted between PARENT and GRANDPARENT.

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