double twoToThe53 = Math.pow(2, 53);
    // the representable doubles are 2^53 and 2^53 + 2.
    // 2^53+1 is halfway between, so HALF_UP will go up and HALF_DOWN will go down.
    new RoundToDoubleTester(BigInteger.valueOf((1L << 53) + 1))
        .setExpectation(twoToThe53, DOWN, FLOOR, HALF_DOWN, HALF_EVEN)
        .setExpectation(Math.nextUp(twoToThe53), CEILING, UP, HALF_UP)
        .roundUnnecessaryShouldThrow()
        .test();
  }

    double twoToThe53 = Math.pow(2, 53);
    // the representable doubles are 2^53 and 2^53 + 2.
    // 2^53+1 is halfway between, so HALF_UP will go up and HALF_DOWN will go down.
    new RoundToDoubleTester(BigInteger.valueOf((1L << 53) + 1))
        .setExpectation(twoToThe53, DOWN, FLOOR, HALF_DOWN, HALF_EVEN)
        .setExpectation(Math.nextUp(twoToThe53), CEILING, UP, HALF_UP)
        .roundUnnecessaryShouldThrow()
        .test();
  }

    double twoToThe53 = Math.pow(2, 53);
    // the representable doubles are 2^53 and 2^53 + 2.
    // 2^53+1 is halfway between, so HALF_UP will go up and HALF_DOWN will go down.
    new RoundToDoubleTester(BigDecimal.valueOf((1L << 53) + 1))
        .setExpectation(twoToThe53, DOWN, FLOOR, HALF_DOWN, HALF_EVEN)
        .setExpectation(Math.nextUp(twoToThe53), CEILING, UP, HALF_UP)
        .roundUnnecessaryShouldThrow()
        .test();
  }

      case UNNECESSARY:
        checkRoundingUnnecessary(isPowerOfTwo(x));
        // fall through
      case DOWN:
      case FLOOR:
        return (Long.SIZE - 1) - Long.numberOfLeadingZeros(x);

      case UP:
      case CEILING:
        return Long.SIZE - Long.numberOfLeadingZeros(x - 1);

      case HALF_DOWN:
      case HALF_UP:
      case HALF_EVEN:

import static java.math.BigInteger.ONE;
import static java.math.BigInteger.ZERO;
import static java.math.RoundingMode.CEILING;
import static java.math.RoundingMode.DOWN;
import static java.math.RoundingMode.FLOOR;
import static java.math.RoundingMode.HALF_DOWN;
import static java.math.RoundingMode.HALF_EVEN;
import static java.math.RoundingMode.HALF_UP;
import static java.math.RoundingMode.UP;
import static java.util.Arrays.asList;

import static java.math.BigInteger.ONE;
import static java.math.BigInteger.ZERO;
import static java.math.RoundingMode.CEILING;
import static java.math.RoundingMode.DOWN;
import static java.math.RoundingMode.FLOOR;
import static java.math.RoundingMode.HALF_DOWN;
import static java.math.RoundingMode.HALF_EVEN;
import static java.math.RoundingMode.HALF_UP;
import static java.math.RoundingMode.UP;
import static java.util.Arrays.asList;

    double twoToThe53 = Math.pow(2, 53);
    // the representable doubles are 2^53 and 2^53 + 2.
    // 2^53+1 is halfway between, so HALF_UP will go up and HALF_DOWN will go down.
    new RoundToDoubleTester(BigDecimal.valueOf((1L << 53) + 1))
        .setExpectation(twoToThe53, DOWN, FLOOR, HALF_DOWN, HALF_EVEN)
        .setExpectation(Math.nextUp(twoToThe53), CEILING, UP, HALF_UP)
        .roundUnnecessaryShouldThrow()
        .test();
  }

        checkRoundingUnnecessary(isPowerOfTwo(x));
        // fall through
      case DOWN:
      case FLOOR:
        return (Integer.SIZE - 1) - Integer.numberOfLeadingZeros(x);

      case UP:
      case CEILING:
        return Integer.SIZE - Integer.numberOfLeadingZeros(x - 1);

      case HALF_DOWN:
      case HALF_UP:
      case HALF_EVEN:

      return requiredFrom; // only one thing to choose, so choose it
    }

    // Find the center and round down. The true center is either centerFloor or halfway between
    // centerFloor and centerFloor + 1.
    int centerFloor = (from + to) >>> 1;

    // Do a binary search until we're down to the range of two which encloses centerFloor (unless

    offer(e); // never need to block
  }

  @CanIgnoreReturnValue // pushed down from class to method
  @Override
  public @Nullable E poll() {
    final Monitor monitor = this.monitor;
    monitor.enter();
    try {
      return q.poll();
    } finally {
      monitor.leave();
    }
  }

  @CanIgnoreReturnValue // pushed down from class to method
  @Override