根据枚举列表验证字符串列表

Question

我有一个.properties文件，其中包含一组属性作为键值对。这被读入配置枚举类。此配置类包含对应于属性的枚举。我希望能够发现两者之间的差异。因此，如果属性文件包含类中不存在的属性，或者相反。换句话说，我有一个枚举数组：MyEnumClass[] enums = {E1,E2,E3}和一个表示枚举的字符串数组String[] properties = {"E1","E2","E3"}我怎样才能找到两者的交集？最好我想避免流。

Answer 1

这是计算交集的简单方法（更改输入以使结果明显）：

List<String> properties = Arrays.asList(new String[] { "E1", "E2" });

List<MyEnumClass> enums = Arrays.asList(new MyEnumClass[] 

                          { MyEnumClass.E2, MyEnumClass.E3 });

List<String> enumNames = new ArrayList<>();

for (MyEnumClass e : enums)

    enumNames.add(e.name());

List<String> intersection = new ArrayList<>(enumNames);

intersection.retainAll(properties);

System.out.println(intersection); //[E2]

这可以计算彼此之间的差异：

List<String> propDiff = new ArrayList<>(properties);

propDiff.removeAll(enumNames);

System.out.println(propDiff); //[E1]

List<String> enumDiff = new ArrayList<>(enumNames);

enumDiff.removeAll(properties);

System.out.println(enumDiff); //[E3]

Answer 2

你可以这样使用EnumSet<MyEnumClass>：

Set<MyEnumClass> all = EnumSet.allOf(MyEnumClass.class);

EnumSet<MyEnumClass>然后从您的属性创建另一个：

Set<MyEnumClass> loaded = EnumSet.noneOf(MyEnumClass.class);

for(String property : properties) {

    loaded.add(MyEnumClass.valueOf(property));

}

Collection.removeAll然后，您可以使用, Collection.addAll,来检查不同的内容Collection.retainAll：

// all will now contain every element from loaded

all.addAll(loaded);

// all will now contain every element which was not contained in loaded

all.removeAll(loaded);

// all will now contain every element which was contained in loaded

all.retainAll(loaded);