src/share/classes/java/util/function/BinaryOperator.java

rev 7485 : 8009736: Comparator API cleanup
Reviewed-by:
Contributed-by: henry.jen@oracle.com

*** 22,31 ****
--- 22,34 ----
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  package java.util.function;
  
+ import java.util.Objects;
+ import java.util.Comparator;
+ 
  /**
   * An operation upon two operands yielding a result. This is a specialization of
   * {@code BiFunction} where the operands and the result are all of the same type.
   *
   * @param <T> the type of operands to {@code apply} and of the result
*** 33,38 ****
--- 36,66 ----
   * @see BiFunction
   * @since 1.8
   */
  @FunctionalInterface
  public interface BinaryOperator<T> extends BiFunction<T,T,T> {
+     /**
+      * Constructs a {@link BinaryOperator} which returns the lesser of two elements
+      * according to the specified {@code Comparator}
+      *
+      * @param  comparator A {@code Comparator} for comparing the two values
+      * @return a {@code BinaryOperator} which returns the lesser of its operands,
+      *         according to the supplied {@code Comparator}
+      */
+     public static<T> BinaryOperator<T> minBy(Comparator<? super T> comparator) {
+         Objects.requireNonNull(comparator);
+         return (a, b) -> comparator.compare(a, b) <= 0 ? a : b;
+     }
+ 
+     /**
+      * Constructs a {@link BinaryOperator} which returns the greater of two elements
+      * according to the specified {@code Comparator}
+      *
+      * @param  comparator A {@code Comparator} for comparing the two values
+      * @return a {@code BinaryOperator} which returns the greater of its operands,
+      *         according to the supplied {@code Comparator}
+      */
+     public static<T> BinaryOperator<T> maxBy(Comparator<? super T> comparator) {
+         Objects.requireNonNull(comparator);
+         return (a, b) -> comparator.compare(a, b) >= 0 ? a : b;
+     }
  }