sorting - 在自引用对象上覆盖compareTo(父/子关系)

Question

我试图在grails的域类上实现compareTo，以便我可以返回SortedSet。我希望我的排序集按父级名称，然后按“子级”名称排序。例如(P = parent ，C = child ):

P-1

C-1

C-2

P-2

C-3

C-4

我的课看起来像这样:

class Issue implements Comparable {
 String name
 Issue parent

@Override
public int compareTo(obj){
  if(obj.parent!=null && this.parent!=null){
   parent.name.compareTo(obj.parent.name)
  }else{
      //What do I compare to sort the children relative to their parents?
  }
}

Answer 1

如果您要查找的只是排序集，那么仅实现“可比较问题”并在映射上使用排序顺序就足够了吗？

class Issue implements Comparable {
 String name
 Issue parent
 SortedSet children

 static hasMany = [children : Issue]
 static belongsTo = [parent : Issue]
 static mapping = {
    sort 'name'
    children sort:'name'
 }    

@Override
public int compareTo(obj){
  if(obj){
    this.name?.compareTo(obj.name)
  }
}