/**
 * Java Collections Framework > TreeSetExample.java
 *
 * Use a TreeSet to store objects and retrieve them quickly.  TreeSets are 
 * slower than HashSets at retrieval but store their elements in sorted order.
 * Note that for ordering to be meaningful, all objects in a given TreeSet must
 * be mutually comparable.
 * @author  Feihong Hsu
 */

import java.util.TreeSet;       // A container that supports quick retrieval;
                                // subclass of SortedSet.
import java.util.Iterator;      // Usful for traversing a TreeSet

public class TreeSetExample {
    
    // This method prints the elements of a given TreeSet object.
    public static void printTreeSet(TreeSet treeSet) {
        System.out.print( "TreeSet: " );
        
        // Use an Iterator to print each element of the TreeSet.
        Iterator iterator = treeSet.iterator();
        while (iterator.hasNext())
            System.out.print( iterator.next() + ", " );
        System.out.println();
    }
    
    public static void main(String[] args) {
        TreeSet treeSet = new TreeSet();
        
        // Add 5 objects to the TreeSet.
        treeSet.add("Viking");
        treeSet.add("Owari");
        treeSet.add("Ainu");
        treeSet.add("Incan");
        treeSet.add("Eskimo");
        
        // "TreeSet: Ainu, Eskimo, Incan, Owari, Viking, "
        // Note that the elements are in sorted order, even though they were 
        // not added in order.
        printTreeSet(treeSet);
        
        // Remove the element from the TreeSet which is a String with 
        // value "Incan".
        treeSet.remove("Incan");
        
        // "TreeSet: Ainu, Eskimo, Owari, Viking, "
        printTreeSet(treeSet);
        
        // Find out if the set contains a String with value "Incan".
        System.out.print( "TreeSet contains Incan? " );
        System.out.println( treeSet.contains("Incan") );        // Prints false
        
        // Add another element to the TreeSet.
        treeSet.add("Zulu");
        
        // "TreeSet: Ainu, Eskimo, Owari, Viking, Zulu, "
        printTreeSet(treeSet);        
        
        treeSet.clear();        // Remove all elements from the TreeSet
    }    
}

/* Output:

TreeSet: Ainu, Eskimo, Incan, Owari, Viking, 
TreeSet: Ainu, Eskimo, Owari, Viking, 
TreeSet contains Incan? false
TreeSet: Ainu, Eskimo, Owari, Viking, Zulu, 

*/