RFR 9: 8138963 : java.lang.Objects new method to default to non-null

[Roger Riggs]

HI Paul,

It simplifies code that looks like this:

followRedirects = builder.followRedirects == null ?
                 Redirect.NEVER : builder.followRedirects;

To:
    followRedirects = Objects.nonNullOrElse(builder.followRedirects, 
Redirect.NEVER);

It makes the source code more concise by not repeating the expression 
twice and
avoids evaluating the expression more than once.

Roger



On 10/6/2015 10:11 AM, Paul Benedict wrote:
> If the second value is allowed to be null, then I don't find this new 
> method useful. What value do you see in it? It doesn't provide any 
> extra functionality to a simple if-else/ternary test, right? I throw 
> my lot in with Stephen that the return value must be non-null.
>
>
> Cheers,
> Paul
>
> On Tue, Oct 6, 2015 at 9:06 AM, Roger Riggs <Roger.Riggs at oracle.com 
> <mailto:Roger.Riggs at oracle.com>> wrote:
>
>     Hi Paul,
>
>     Hence the question about the method name.
>     It already documents explicitly that the nullDefault value is
>     returned and does not restrict the value.
>
>     To be a direct replacement for the current code, it should return
>     the 2nd value regardless of whether it is null or not.
>
>     Roger
>
>
>
>
>     On 10/6/2015 9:56 AM, Paul Benedict wrote:
>>     It's quite possible for the second argument to be null. Is that
>>     your intention? I am not sure it makes sense, but it's not
>>     harmful either. I recommend you can either (1) explicitly
>>     document that's a possibility and this method could still return
>>     null or (2) prevent it by calling requireNonNull.
>>
>>
>>     Cheers,
>>     Paul
>>
>>     On Tue, Oct 6, 2015 at 8:43 AM, Roger Riggs
>>     <Roger.Riggs at oracle.com <mailto:Roger.Riggs at oracle.com>> wrote:
>>
>>         Java.lang.Objects contains a number of convenience methods to
>>         make it easier to handle references that are null.
>>         For example, toString(obj, nullDefault),
>>
>>         A new method is proposed to return the reference or a default
>>         value if the reference is null.
>>            static <T> T nonNull(T obj, T nullDefault);
>>
>>         Alternatives to the method name include
>>         nonNullOrElse ( using the java.util.Optional name pattern) or
>>         nonNullOrDefault
>>
>>         Please review and comment.
>>
>>         Webrev:
>>         http://cr.openjdk.java.net/~rriggs/webrev-object-non-null/
>>         <http://cr.openjdk.java.net/%7Erriggs/webrev-object-non-null/>
>>
>>         Issue:
>>         https://bugs.openjdk.java.net/browse/JDK-8138963
>>
>>         Thanks, Roger
>>
>>
>
>