Generics 和 mockito 中的 ArgumentCaptor

Question

in mockito's verify i want to capture an argument of type Consumer<String> . How should i write the line to avoid type erasure?

I'm reached the this point and it doesn't compile

ArgumentCaptor<Consumer<String>> captor = ArgumentCaptor.<Consumer<String>, Consumer<String>>forClass(Consumer<String>.class);

how can i do it?

Answer 1

As stated in the documentation of ArgumentCaptor although this class is generic, it doesn't perform any validation:

This utility class don't do any type checks , the generic signatures are only there to avoid casting in your code.

Hence, if you make use of row types it wouldn't be less type-safe, but there's a drawback - the compiler will issue a warning.

@SuppressWarnings("unchecked")
ArgumentCaptor<Consumer<String>> captor = ArgumentCaptor.forClass(Consumer.class);

There's a cleaner option which also mentioned in the documentation linked above, namely to declare the captor as a field and annotate it with @Captor .

@Captor
ArgumentCaptor<Consumer<String>> captor;