How to express a predicate of equality in Java?

Question

I have the following expression:

final String idStatusAutorizada = ...; // valor constante
return pendencias.stream()
    .map(TipoBlocCarga::getIdStatus)
    .anyMatch(idStatusPendencia -> !idStatusAutorizada.equals(idStatusPendencia));

But the latter lambda is not satisfying me aesthetically. I would like to turn into some kind of method reference. Another alternative that I don’t like is to declare a variable with the predicate of idStatusAutorizada::equals and pass the method to the function of that predicate with negate(), but I must say that I do not yet seem sufficiently elegant:

final String idStatusAutorizada = ...; // valor constante
Predicate<String> equalsAutorizada = idStatusAutorizada::equals;
return pendencias.stream()
    .map(TipoBlocCarga::getIdStatus)
    .anyMatch(equalsAutorizada.negate());

I would find it beautiful if it were possible to do idStatusAutorizada::equals.negate(), but Java 8 does not allow this. I don’t know if this has changed in the latest versions, but I can’t change the version of Java in my code because of the platforms on which the code will be executed.

So, my question: is it possible to make a predicate of equality in Java?

Answer 1

^{The solutions below are a compilation of the answers of this question.}

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If you want to use the method Reference and does not want to create a variable just to save the Predicate, can even do. It’s just not as "beautiful" as you’d like, because it involves making a cast of method Reference for Predicate, so it is possible to call the method negate:

return pendencias.stream()
    .map(TipoBlocCarga::getIdStatus)
    .anyMatch(((Predicate<String>) idStatusAutorizada::equals).negate());

^{Maybe I got even more "ugly" than your alternatives...}

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Starting from Java 11, there is the static method Predicate.not, to which you can directly pass the method Reference:

return pendencias.stream()
    .map(TipoBlocCarga::getIdStatus)
    .anyMatch(Predicate.not(idStatusAutorizada::equals));

But if you are using Java < 11, there is still the possibility to create a similar method:

public static <T> Predicate<T> not(Predicate<T> predicate) {
    return predicate.negate();
}

...
return pendencias.stream()
    .map(TipoBlocCarga::getIdStatus)
    .anyMatch(not(idStatusAutorizada::equals));