Question

JodaTime has

public final class DateTime extends BaseDateTime {...}

which works its way up to

public interface ReadableInstant extends Comparable<ReadableInstant>

Hamcrest has

public static <T extends java.lang.Comparable<T>> org.hamcrest.Matcher<? super T>
    greaterThan(T value) {...}

If I try

greaterThan(new DateTime());

then I get a compile error (Eclipse gives most clue)

The generic method greaterThan(T) of type Matchers is not applicable
for the arguments (DateTime). The inferred type DateTime is not a valid substitute
for the bounded parameter >

Am I right in thinking that the signature of greaterThan should actually be

public static <T extends java.lang.Comparable<? super T>> org.hamcrest.Matcher<? super T>     
    greaterThan(T value)

? And is there a way to fit these together short of casting to the raw Comparable?

Answer 1

Yes, it looks to me like that would be a better signature.

Have you tried specifying the comparison type explicitly?

Matchers.<ReadableInstant>greaterThan(new DateTime());

I don’t believe you can call it using a static import and also specifying the type argument, unfortunately – but that may not be too much of hardship.

Of course an alternative is to cast the argument:

greaterThan((ReadableInstant) new DateTime());

I don’t have Hamcrest handy, but the above worked fine for me using the signature you’d given me, in a test type.