src/java.base/share/classes/java/util/Set.java

rev 48077 : 8193128: Reduce number of implementation classes returned by List/Set/Map.of()
Reviewed-by: smarks

*** 447,457 ****
       * @return an empty {@code Set}
       *
       * @since 9
       */
      static <E> Set<E> of() {
!         return ImmutableCollections.Set0.instance();
      }
  
      /**
       * Returns an unmodifiable set containing one element.
       * See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
--- 447,457 ----
       * @return an empty {@code Set}
       *
       * @since 9
       */
      static <E> Set<E> of() {
!         return ImmutableCollections.emptySet();
      }
  
      /**
       * Returns an unmodifiable set containing one element.
       * See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*** 462,472 ****
       * @throws NullPointerException if the element is {@code null}
       *
       * @since 9
       */
      static <E> Set<E> of(E e1) {
!         return new ImmutableCollections.Set1<>(e1);
      }
  
      /**
       * Returns an unmodifiable set containing two elements.
       * See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
--- 462,472 ----
       * @throws NullPointerException if the element is {@code null}
       *
       * @since 9
       */
      static <E> Set<E> of(E e1) {
!         return new ImmutableCollections.Set12<>(e1);
      }
  
      /**
       * Returns an unmodifiable set containing two elements.
       * See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*** 479,489 ****
       * @throws NullPointerException if an element is {@code null}
       *
       * @since 9
       */
      static <E> Set<E> of(E e1, E e2) {
!         return new ImmutableCollections.Set2<>(e1, e2);
      }
  
      /**
       * Returns an unmodifiable set containing three elements.
       * See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
--- 479,489 ----
       * @throws NullPointerException if an element is {@code null}
       *
       * @since 9
       */
      static <E> Set<E> of(E e1, E e2) {
!         return new ImmutableCollections.Set12<>(e1, e2);
      }
  
      /**
       * Returns an unmodifiable set containing three elements.
       * See <a href="#unmodifiable">Unmodifiable Sets</a> for details.
*** 690,704 ****
      @SafeVarargs
      @SuppressWarnings("varargs")
      static <E> Set<E> of(E... elements) {
          switch (elements.length) { // implicit null check of elements
              case 0:
!                 return ImmutableCollections.Set0.instance();
              case 1:
!                 return new ImmutableCollections.Set1<>(elements[0]);
              case 2:
!                 return new ImmutableCollections.Set2<>(elements[0], elements[1]);
              default:
                  return new ImmutableCollections.SetN<>(elements);
          }
      }
  
--- 690,704 ----
      @SafeVarargs
      @SuppressWarnings("varargs")
      static <E> Set<E> of(E... elements) {
          switch (elements.length) { // implicit null check of elements
              case 0:
!                 return ImmutableCollections.emptySet();
              case 1:
!                 return new ImmutableCollections.Set12<>(elements[0]);
              case 2:
!                 return new ImmutableCollections.Set12<>(elements[0], elements[1]);
              default:
                  return new ImmutableCollections.SetN<>(elements);
          }
      }