java - 如何按枚举的顺序对 List<Enum, Collection> 进行排序？

Question

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));  

如何根据枚举顺序对列表进行排序？

Answer 1

您应该简单地委托(delegate)给已经提供的枚举 compareTo 方法并反射(reflect)声明顺序(基于 ordinal 值):

Collections.sort(list, (a1, a2) -> 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”，您可以让 A 类本身实现 Comparable 并委托(delegate) compareTo ComponentType 方法。