schananas/practical-reactor

Practical Project Reactor and reactive programing workshop

practical-reactor's Issues

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This is the place where you can post your feedback about exercises.

Are exercises too hard?
Are requirements clear enough?
How much time took you to finish all exercises?
Do you feel that your knowledge about Reactor improved after doing this workshop?
Any proposals for improvements or new exercises?

Can't pass exercise c4_LifecycleHooks need_to_cancel when upgrade reactor-core package.

I use the code below

        AtomicBoolean canceled = new AtomicBoolean(false);

        Flux<Integer> temperatureFlux = room_temperature_service()
                .doOnCancel(() -> canceled.set(true)) //todo: change this line only
                ;

        StepVerifier.create(temperatureFlux.take(0))
                    .expectNextCount(0)
                    .verifyComplete();

        Assertions.assertTrue(canceled.get());

The test case can pass when i use reactor-core:3.4.14.
But it can't pass when is use reactor-core:3.5.0-m2.
Is this a bug of reactor-core:3.5.0-m2 or has the behavior changed on eactor-core:3.5.0-m2?
I don't know how to fix it.

c3_FilteringSequence.java has confusing comment

practical-reactor/exercises/src/test/java/c3_FilteringSequence.java

Line 44 in 895dd6d

Flux<String> strings = null;

The comment creates confusion, because we actually need to adjust the first line to remove the null and instead call the service and save the result to strings variable.

Something like this would be better.

        Flux<String> strings = null;
        mashed_data_service()
                //todo: replace null with mashed_data_service() call  and your solution.
                ;

c3_Filtering_sequence - golden_middle test and solution is wrong

In the solution:

/**
  * `number_service()` returns 300 numbers, but you only need 100 numbers, from the middle.
  */
 @Test
 public void golden_middle() {
     Flux<Integer> numbers = number_service()
             .skip(100) //this should be .skip(150) as 300/2 = 150
             .take(100)
             ;

     StepVerifier.create(numbers)
                 .expectNextMatches(i -> i >= 100) // this should be expectNextMatches(i -> i >= 100), as the middle number is 150
                 .expectNextCount(99)
                 .verifyComplete();
 }

Parameter order is different.

Hi, thank you for the project.

In c4_LifecycleHooks line 78,

@Test
    public void atomic_counter() {
        AtomicInteger counter = new AtomicInteger(0);

       ...

        //I think wrong order.
        Assertions.assertEquals(counter.get(), 20);
    }

it change to

    Assertions.assertEquals(20, counter.get());

because 20 is expected value.

thank you.