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From Gary Gregory <garydgreg...@gmail.com>
Subject Re: Pair of nulls
Date Thu, 11 May 2017 16:17:13 GMT
On Thu, May 11, 2017 at 5:35 AM, Matt Benson <gudnabrsam@gmail.com> wrote:

> On May 11, 2017 1:03 AM, "Gary Gregory" <garydgregory@gmail.com> wrote:
>
> On Wed, May 10, 2017 at 10:58 PM, Matt Sicker <boards@gmail.com> wrote:
>
> > Matching the of() static factories, how about ImmutablePair.ofNull()
> >
>
> I like it but at the same time it feels to me like I am getting a NEW
> object like ImmutablePair.of(x, y) give me a new object. Might just be me
> ;-)
>
>
> You provide the methods so that people can get an instance parameterized
> for their compilation needs. In reality you can return the same empty,
> immutable instance.
>

Yes, of course:

    /**
     * An immutable pair of nulls.
     */
    // This is not defined with generics to avoid warnings in call sites.
    @SuppressWarnings("rawtypes")
    private static final ImmutablePair NULL = ImmutablePair.of(null, null);

    @SuppressWarnings("rawtypes")
    // This is not defined with generics to avoid warnings in call sites.
    public static ImmutablePair nullPair() {
        return NULL;
    }

Gary



>
> Matt
>
>
> Gary
>
>
> > On 11 May 2017 at 00:03, Gary Gregory <garydgregory@gmail.com> wrote:
> >
> > > On Wed, May 10, 2017 at 9:27 PM, Matt Sicker <boards@gmail.com> wrote:
> > >
> > > > Wouldn't it make sense to expose typed methods like in
> > > > Collections.emptyList() et al.?
> > > >
> > >
> > > So in this case:
> > >
> > > ImmutablePair.nullPair()
> > >
> > > Gary
> > >
> > > >
> > > > On 10 May 2017 at 22:10, Javen O'Neal <onealj@apache.org> wrote:
> > > >
> > > > > +1
> > > > >
> > > > > The of method should check if all elements are null, and if so to
> > > return
> > > > > the NULL singleton. This would reduce the number of objects created
> > and
> > > > > garbage collected.
> > > > >
> > > > > So long as ImmutablePair and ImmutableTriple classes are final (not
> > > > > subclassable), then identity checking could be used in place of
> > > equality
> > > > > checking when comparing against a null tuple. This would be
> > marginally
> > > > > faster.
> > > > >
> > > > > Any preference of being explicit (redundant) here?
> > > > > ImmutablePair.NULL_PAIR and ImmutableTriple.NULL_TRIPLE
> > > > >
> > > > > On May 10, 2017 7:35 PM, "Gary Gregory" <garydgregory@gmail.com>
> > > wrote:
> > > > >
> > > > > Hi All,
> > > > >
> > > > > Any thoughts for or against adding the following to ImmutablePair:
> > > > >
> > > > >
> > > > >     /**
> > > > >      * An immutable pair of nulls.
> > > > >      */
> > > > >     // This is not defined with generics to avoid warnings in call
> > > sites.
> > > > >     @SuppressWarnings("rawtypes")
> > > > >     public static final ImmutablePair NULL = ImmutablePair.of(null,
> > > > null);
> > > > >
> > > > > Same for ImmutableTriple.
> > > > >
> > > > > ?
> > > > >
> > > > > Thank you,
> > > > > Gary
> > > > >
> > > > > --
> > > > > E-Mail: garydgregory@gmail.com | ggregory@apache.org
> > > > > Java Persistence with Hibernate, Second Edition
> > > > > <https://www.amazon.com/gp/product/1617290459/ref=as_li_
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> > > > > Home: http://garygregory.com/
> > > > > Tweet! http://twitter.com/GaryGregory
> > > > >
> > > >
> > > >
> > > >
> > > > --
> > > > Matt Sicker <boards@gmail.com>
> > > >
> > >
> > >
> > >
> > > --
> > > E-Mail: garydgregory@gmail.com | ggregory@apache.org
> > > Java Persistence with Hibernate, Second Edition
> > > <https://www.amazon.com/gp/product/1617290459/ref=as_li_
> > > tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1617290459&
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> >
> >
> >
> > --
> > Matt Sicker <boards@gmail.com>
> >
>
>
>
> --
> E-Mail: garydgregory@gmail.com | ggregory@apache.org
> Java Persistence with Hibernate, Second Edition
> <https://www.amazon.com/gp/product/1617290459/ref=as_li_
> tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1617290459&
> linkCode=as2&tag=garygregory-20&linkId=cadb800f39946ec62ea2b1af9fe6a2b8>
>
> <http:////ir-na.amazon-adsystem.com/e/ir?t=garygregory-20&l=am2&o=1&a=
> 1617290459>
> JUnit in Action, Second Edition
> <https://www.amazon.com/gp/product/1935182021/ref=as_li_
> tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1935182021&
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> Blog: http://garygregory.wordpress.com
> Home: http://garygregory.com/
> Tweet! http://twitter.com/GaryGregory
>



-- 
E-Mail: garydgregory@gmail.com | ggregory@apache.org
Java Persistence with Hibernate, Second Edition
<https://www.amazon.com/gp/product/1617290459/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1617290459&linkCode=as2&tag=garygregory-20&linkId=cadb800f39946ec62ea2b1af9fe6a2b8>

<http:////ir-na.amazon-adsystem.com/e/ir?t=garygregory-20&l=am2&o=1&a=1617290459>
JUnit in Action, Second Edition
<https://www.amazon.com/gp/product/1935182021/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1935182021&linkCode=as2&tag=garygregory-20&linkId=31ecd1f6b6d1eaf8886ac902a24de418%22>

<http:////ir-na.amazon-adsystem.com/e/ir?t=garygregory-20&l=am2&o=1&a=1935182021>
Spring Batch in Action
<https://www.amazon.com/gp/product/1935182951/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=1935182951&linkCode=%7B%7BlinkCode%7D%7D&tag=garygregory-20&linkId=%7B%7Blink_id%7D%7D%22%3ESpring+Batch+in+Action>
<http:////ir-na.amazon-adsystem.com/e/ir?t=garygregory-20&l=am2&o=1&a=1935182951>
Blog: http://garygregory.wordpress.com
Home: http://garygregory.com/
Tweet! http://twitter.com/GaryGregory

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