Hi Joe,
Overall this looks quite good. Thanks for being thorough about this; I certainly
would have forgotten about StrictMath. :-) Since this is integer arithmetic, is
it true that the StrictMath versions are identical to the Math versions?
I have only a couple editorial quibbles.
+ * {@code int} range and an exception is thrown for that argument.
Recommend adding a comma here:
+ * {@code int} range, and an exception is thrown for that argument.
--
+ * @return the absolute value of the argument absent overflow
I stumbled while reading this. While not incorrect, it seems a bit awkwardly
worded to me. How about something like "...the argument, unless overflow occurs."
--
+ throw new ArithmeticException("Cannot represent " +
+ "absolute value of " +
+ "Integer.MIN_VALUE");
In cases like this I usually prefer to put the entire string on its own line,
avoiding the concatenation:
+ throw new ArithmeticException(
+ "Cannot represent absolute value of Integer.MIN_VALUE");
--
Thanks,
s'marks
On 3/28/20 1:34 PM, Joe Darcy wrote:
Hello,
Please review the initial proposed wording of the spec for
JDK-8241374: add Math.absExact
The eventual wording needs to be replicated four times (Math.absExact(int),
Math.absExact(long), StrictMath.absExact(int), StrictMath.absExact(long)) so I
want to get the wording agreed to before presenting it in quadruplicate.
The other "exact" methods mention overflow so I wanted the spec to absExact to
include both "exact" and "overflow" in its description.
Tests will follow in subsequent review iterations.
Thanks,
-Joe
diff -r c5d90e8d4a46 src/java.base/share/classes/java/lang/Math.java
--- a/src/java.base/share/classes/java/lang/Math.java Sat Mar 28 11:00:09
2020 -0400
+++ b/src/java.base/share/classes/java/lang/Math.java Sat Mar 28 10:17:39
2020 -0700
@@ -1369,6 +1369,32 @@
}
/**
+ * Returns the mathematical absolute value of an {@code int} value
+ * if it is exactly representable as an {@code int}, throwing
+ * {@code ArithmeticException} if the result overflows the
+ * positive {@code int} range.
+ *
+ * <p>Since the range of two's complement integers is asymmetric
+ * with one additional negative value, the mathematical absolute
+ * value of {@link Integer#MIN_VALUE} overflows the positive
+ * {@code int} range and an exception is thrown for that argument.
+ *
+ * @param a the argument whose absolute value is to be determined
+ * @return the absolute value of the argument absent overflow
+ * @throws ArithmeticException if the argument is {@link Integer#MIN_VALUE}
+ * @see Math#abs(int)
+ * @since 15
+ */
+ public static int absExact(int a) {
+ if (a == Integer.MIN_VALUE)
+ throw new ArithmeticException("Cannot represent " +
+ "absolute value of " +
+ "Integer.MIN_VALUE");
+ else
+ return abs(a);
+ }
+
+ /**
* Returns the absolute value of a {@code long} value.
* If the argument is not negative, the argument is returned.
* If the argument is negative, the negation of the argument is returned.
