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

rev 6189 : 8004015: Add Extends and deaults for basic functional interface types
Summary: Adds the appropriate extends and default methods for  core functional interfaces used by the JSR335 libraries.
Reviewed-by: duke

*** 26,38 ****
  
  /**
   * An operation on a single {@code double} operand yielding a {@code double}
   * result.
   *
   * @since 1.8
   */
! public interface DoubleUnaryOperator {
  
      /**
       * Returns the {@code double} result of the operation upon the
       * {@code double} operand.
       *
--- 26,55 ----
  
  /**
   * An operation on a single {@code double} operand yielding a {@code double}
   * result.
   *
+  * <p>This is the primitive type specialization of {@link UnaryOperator} for
+  * {@code double} and also may be used as a {@code UnaryOperator<Double>}. When
+  * used as a {@code UnaryOperator} the default {@code operate} implementation
+  * provided by this interface neither accepts null parameters nor does it return
+  * null results.
+  *
   * @since 1.8
   */
! public interface DoubleUnaryOperator extends UnaryOperator<Double> {
! 
!     /**
!      * {@inheritDoc}
!      *
!      * @param operand {@inheritDoc}, must be non-null
!      * @return {@inheritDoc}, always non-null
!      */
!     @Override
!     public default Double operate(Double operand) {
!         return operateAsDouble((double)operand);
!     }
  
      /**
       * Returns the {@code double} result of the operation upon the
       * {@code double} operand.
       *