Source of SetClasses.java


  1: import java.util.HashSet;
  2: import java.util.LinkedHashSet;
  3: import java.util.List;
  4: import java.util.Set;
  5: import java.util.TreeSet;

  7: /**
  8:  *
  9:  * @author Mark Young (A00000000)
 10:  */
 11: public class SetClasses {

 13:     /**
 14:      * @param args the command line arguments
 15:      */
 16:     public static void main(String[] args) {
 17:         Set<String> treeSet = new TreeSet<>();
 18:         Set<String> linkedHashSet = new LinkedHashSet<>();
 19:         Set<String> hashSet = new HashSet<>();
 20:         
 21:         // introduce yourself
 22:         System.out.println("I have created three Sets:");
 23:         System.out.println(" - a TreeSet");
 24:         System.out.println(" - a LinkedHashSet");
 25:         System.out.println(" - a HashSet");
 26:         System.out.println("Let's see what they do with their elements");
 27:         System.out.println();

 29:         // add items
 30:         for (String item : List.of("S", "O", "M", "E")) {
 31:             System.out.println("Adding \"" + item + "\" to all sets");
 32:             treeSet.add(item);
 33:             linkedHashSet.add(item);
 34:             hashSet.add(item);
 35:         }
 36:         System.out.println();
 37:         
 38:         // show results
 39:         System.out.println("Here is what the sets look like:");
 40:         System.out.println(" - TreeSet:       " + treeSet);
 41:         System.out.println(" - LinkedHashSet: " + linkedHashSet);
 42:         System.out.println(" - HashSet:       " + hashSet);
 43:         System.out.println();
 44:         
 45:         // add more items
 46:         for (String item : List.of("M", "O", "R", "E")) {
 47:             System.out.println("Adding \"" + item + "\" to all sets");
 48:             treeSet.add(item);
 49:             linkedHashSet.add(item);
 50:             hashSet.add(item);
 51:         }
 52:         System.out.println();
 53:         
 54:         System.out.println("Here is what the sets look like now:");
 55:         System.out.println(" - TreeSet:       " + treeSet);
 56:         System.out.println(" - LinkedHashSet: " + linkedHashSet);
 57:         System.out.println(" - HashSet:       " + hashSet);
 58:         System.out.println();

 60:         System.out.println("The TreeSet keeps things sorted");
 61:         System.out.println("The LinkedHashSet keeps things "
 62:                 + "in the order they were entered");
 63:         System.out.println("The HashSet keeps things ... mixed up?");
 64:         System.out.println();
 65:     }

 67: }