Hi Stian,
thx for ur +1
The rational behind equalsOneOf(null, null)== false, is thatÂ
a) all or most methods in this class with varargs==null result in false
b) it also enforce the notion of the name, that i'm comparing against a
"collection of values" and this collection is set up by me in source code right
now.
For other cases, where i already have an array or know its just one var i
wouldnt need this and could use Objects.equals() or ArrayUtils.contains(). For
the latter i now can use this new method as well.
tom
> Stian Soiland-Reyes <st...@apache.org> hat am 7. August 2016 um 07:42
> geschrieben:
>
> +1 for the proposal!
>
> I think ObjectUtils is a good home, the implied array or collection is an
> implementation detail.
>
> What is your reasoning for null != null ?
>
> If you accept a Function to compare with, that would break the varargs
> mechanism (or always require a Function), perhaps such a function could
> have a more functional name like firstWhich ? (Which first argument is a
> selector function)
>
> On 6 Aug 2016 10:43 p.m., "thomas menzel" <d...@tomsit.de> wrote:
>
> Hi folks,
>
> I'm proposing a new function on ObjectsUtils:
>
> /**
>
> * Checks if the given {@code ref} is contained at least once in
>
> * {@code others}. If {@code} is null or empty then {@code false} is
>
> * returned.
>
> *
>
> * This is a more readable replacement for the idiomatic:
>
> * {@code Arrays.asList(others).contains(ref)}.
>
> *
>
> *
>
> * ObjectUtils.equalsOneOf(1, 2, 1)) = true
>
> * ObjectUtils.equalsOneOf(1, 1, 2)) = true
>
> * ObjectUtils.equalsOneOf(1, null, 1)) = true
>
> * ObjectUtils.equalsOneOf(null, 1, null)) = true
>
> * ObjectUtils.equalsOneOf("b", "a b c".split(" "))) = true
>
> * ObjectUtils.equalsOneOf(null, null)) = false
>
> * ObjectUtils.equalsOneOf(1, null)) = false
>
> * ObjectUtils.equalsOneOf(null, new Object[0])) = false
>
> * ObjectUtils.equalsOneOf(1, 2, 3)) = false
>
> *
>
> *
>
> * @param ref
>
> * the ref value to check the others against
>
> * @param others
>
> * the others
>
> * @return true, iff {@code ref} is contained at least once in
>
> * {@code others}
>
> * @since 3.5
>
> */
>
> public static boolean equalsOneOf(final Object ref, final Object...
> others) {
>
> return ArrayUtils.isNotEmpty(others) &&
> ArrayUtils.contains(others, ref);
>
> }
>
> Use Case:
>
> comparing a value to several others in a condition thus avoiding the often
> seen
>
> Other1.equals(string) || Other2.equals(string) || .
>
> Since this is a shorthand for the above, the OTHER values are usually not in
> a collection, e.g.
>
> ObjectUtils.equalsOneOf(e, FooEnum.X, FooEnum.Y );
>
> ObjectUtils.equalsOneOf(string, "A", "B", "C");
>
> One could also accomplish the same thing with:
>
> Arrays.asList(Other1, Other2, ..).contains(ref) but this is less readable
> and also the List is created needlessly.
>
> Note, there is a similar function on StringUtils:
>
> containsAny(CharSequence cs, CharSequence...
> searchCharSequences)
>
> but obviously only for Strings and doing the "conains" check vs. the
> proposed equals-check.
>
> The code for the function is in the last commit of the fork and includes a
> full unit test:
>
> https://github.com/elonderin/commons-lang-equalsOneOf
>
> As a bonus I have also added the companion functions in the same commit:
>
> public static boolean allNull(final Object... values)
>
> public static boolean anyNull(final Object... values)
>
> which is in the same vain as isNull/isNotNull etc. to promote readability.
>
> Also with unit tests.
>
> Hope u like these and add them to the grand collection of util functions.
>
> Thomas Menzel
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