Sorting a LinkedHashSet

Question

I\'m wondering if it\'s possible to sort a LinkedHashSet. I\'ve tried the statement

Collections.sort((List paragraph);

Howeve

Answer 1

You can add LinkedHashSet object (linkedHashSet) to TreeSet and it will be sorted.

TreeSet<T> treeSet = new TreeSet<t>();
treeSet.addAll(linkedHashSet);

treeSet is the sorted set.

Note that you need to make these T type comparable(by implementing Comparator interface).

Answer 2

You should use a SortedSet such as TreeSet or ConcurrentSkipListSet if you care about ordering based on comparison (e.g., sorted order).

A LinkedHashSet preserves order based on insertion order.

If you really want to use Collections.sort you can convert the LHS into a List by actually constructing a List (though the question doesn't tell us the type of paragraph so I'll assume it is String)

List<String> listParagraph = new ArrayList<String>(paragraph);
Collections.sort(listParagraph)

but that's probably not the best approach.

Answer 3

Yes, You can. Java 8 has made our life easier :)

creating a linked list (it looks simple to me, you can directly insert in LinkedHashSet)

LinkedList<String> lList = new LinkedList<String>();
lList.add("Ravi");
lList.add("Vijay");
lList.add("Ravi");
lList.add("Ajay");
lList.add(null);

LinkedHashSet<String> lHashSet = new LinkedHashSet<>();
lHashSet.addAll(lList);

let's sort now

lHashSet.stream().sorted((String s1,String s2)->{       
    return s1.compareTo(s2);
});

//now print it
System.out.println("----");
lHashSet.forEach(action->{
   System.out.println(action);
});
System.out.println("----");

Output-

----
Ravi
Vijay
Ajay
null
----

Happy Coding :)

Answer 4

Collections.sort does not work on Sets, only on Lists. If you need to sort the data that is already in a Set, you might want to first add them into a List.