package collections.sets;

import java.util.Iterator;
import java.util.List;
import java.util.NavigableSet;
import java.util.SortedSet;
import java.util.TreeSet;

public class UsingTreeSet {
	public static void main(String[] args) {
		
		// Using the natural order
		TreeSet<String> set = new TreeSet<>(List.of("A", "C", "B")); // [A,B,C]
		
		// Using a user-defined order, e.g., case insensitive
		set = new TreeSet<>(String.CASE_INSENSITIVE_ORDER);
		set.addAll(List.of("A", "b", "C")); // [A,b,C]
		
		// Using a custom comparator for the user-defined order by length
		set = new TreeSet<>((a,b) -> a.length() - b.length());
		set.addAll(List.of("AA", "B", "CCC")); // [B, AA, CCC]
		
		// Modifying the set
		set = new TreeSet<>(List.of("C","B")); // [B,C]
		set.add("A"); // [A,B,C]
		set.add("D"); // [A,B,C,D]
		String letter = set.removeFirst(); // [B,C,D]
		letter = set.removeLast(); // [B,C]
		// set.addFirst("A"); // throws UnsupportedOperationException
		
		// Querying the set
		set = new TreeSet<>(List.of("d","b","a","e","c")); // [a,b,c,d,e] 
		String first = set.first(); 		// -> a
		String last = set.last(); 			// -> e
		String lower = set.lower("c");      // -> b
		String floor = set.floor("c"); 		// -> c
		String ceiling = set.ceiling("c"); 	// -> c
		String higher = set.higher("c");    // -> d

		// Producing subsets views
		SortedSet<String> head = set.headSet("c"); 		 // [a,b]
		SortedSet<String> tail = set.tailSet("c"); 		 // [c,d,e]
		SortedSet<String> subset = set.subSet("b", "d"); // [b,c]

		// Removing elements
		set.pollFirst(); 	// [b,c,d,e] -> a
		set.removeFirst();  // [c,d,e] -> b
		// See also pollLast and removeLast
		
		// Working with the reverse order: iterators and descending sets
		set = new TreeSet<>(List.of("d","b","a","e","c")); // [a,b,c,d,e] 
		for (Iterator<String> iterator = set.descendingIterator(); iterator.hasNext(); ) {
			System.out.println(iterator.next());
		}
		NavigableSet<String> reversed = set.descendingSet();
		for (String letter2 : reversed) {
			System.out.println(letter2);
		}
		last = reversed.first(); // -> e
	}
}