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From Paul Benedict <pbened...@apache.org>
Subject Re: [lang] new method: ObjectsUtils.equalsOneOf()
Date Sat, 06 Aug 2016 21:43:42 GMT
Hi Thomas. The only issue I see with introducing a "equalsOneOf" is that it
setups the pondering for other uses... greater than one of, less than one
of, and whatever of one of. With that said, I would rather see the proposed
method accept a function/visitor callback to determine the check. If you're
dealing with an array, I would put this inside of ArrayUtils. Otherwise, if
you really have a collection, I already know Commons Collections can do
what you want with a callback.

Cheers,
Paul

On Sat, Aug 6, 2016 at 3:43 PM, thomas menzel <dev@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.
>
>      * <p>
>
>      * This is a more readable replacement for the idiomatic:
>
>      * {@code Arrays.asList(others).contains(ref)}.
>
>      *
>
>      * <pre>
>
>      * 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
>
>      * </pre>
>
>      *
>
>      * @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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