RFR 9: 8138963 : java.lang.Objects new method to default to non-null
Roger.Riggs at Oracle.com
Wed Oct 7 22:24:26 UTC 2015
The original intent was to simplify the filling in of default values
(even if null).
I took Remi's point about the canonical coalescing operator not always
but the push seems to be in the direction of making sure the result is
I'd rather add a few very useful methods and avoid those with
I note that nulls are discovered eventually, but doing more aggressive
checking is preferred.
I expect the compiler is able to squeeze out all the extra checks.
In the current context of Objects that the jdk, I read the naming
pattern of firstNonNull to imply
access to some sequential data structure like an array or list; but it
doesn't gel with me to apply it to the arg list
(unless it was varargs). The pattern of naming us "of" as being
factory producing an object
from the arguments seems apropos and is concise.
Please consider and comment:
<T> T nonNullOf(T obj, T defaultObj);
<T> T nonNullOf(T, obj, Supplier<T> defaultSupplier);
Details are in the updated webrev:
On 10/6/2015 6:42 PM, Remi Forax wrote:
> Null coalescing is a popular operator in several languages  and the usual semantics is nullOrElse and not firstNonNull.
> In languages like Kotlin or Swift, because there is a distinction between Object and Object?, it's not a big deal, you can not de-reference null by error, anyway.
> Also note that nullOrElseGet, the one that takes a supplier also exists in Groovy and Kotlin under the name null safe navigation.
> So even if i prefer the semantics of firstNonNull, i think we should also include both nullOrElse and nullOrElseGet.
>  https://en.wikipedia.org/wiki/Null_coalescing_operator
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