如何排序列表<枚举，集合>通过枚举的顺序？ [英] How to sort a List<Enum, Collection> by order of an enum?

问题描述

枚举：

 public enum ComponentType {
    INSTRUCTION, ACTION, SERVICE, DOMAIN, INTEGRATION,  OTHER, CONTEXT;
 }

A类：

 public class A
 {
    String name;
    ComponentType c;
    public A(String name, ComponentType c)
    {
      this.name = name;
      this.c = c;
    }

 }   

代码：

 List<A> l = new ArrayList<A>();
 l.add(new A("ZY", ACTION));  
 l.add(new A("ZY0", INSTRUCTION));  
 l.add(new A("ZY1", DOMAIN));  
 l.add(new A("ZY2", SERVICE));  
 l.add(new A("ZY3", INSTRUCTION));  
 l.add(new A("ZY4", ACTION));  

如何根据枚举顺序排列列表？

How to sort list according to enum order?

推荐答案

您应该简单地委托已经提供的枚举compareTo（）方法，并反映声明顺序（基于 ordinal value）：

You should simply delegate to the enum compareTo() method which is already provided and reflects the declaration order (based on the ordinal value):

Collections.sort(list, new Comparator() {
    @Override
    public int compare(A a1, A a2) {
        return a1.getType().compareTo(a2.getType());
    }
});

或者，如果您认为组件类型为您的元素提供自然顺序，您可以使A类本身实现 Comparable ，并将 compareTo 方法委托给 ComponentType 一。

Or, if you think that the component type provides the "natural order" for your elements, you can make the A class itself implement Comparable and also delegate the compareTo method to the ComponentType one.

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