How do i perform this operation

[vernal vine]

I am trying to perform operation for a post (question) in my project,

List<Post> acceptedAnswer = question.getAnswers().stream()
                    .filter(ans -> Objects.equals(ans.getStatus(), PostStatus.ACCEPTED))
                    .toList();
            
            if(acceptedAnswer.size() != 1) {
               log.error("Invalid accepted answers for a closed question {}", question.getId()); 
            }

is this correct way to retrieve the accepted answer (each question can have atmost 1), in earlier logics i have made sure there cannot be more than 1 accepted answer so do i need this additional check, if not how do i code to receive single value instead of list

[regal knoll]

Detected code, here are some useful tools:

Formatted code

List<Post> acceptedAnswer = question.getAnswers().stream().filter(ans -> Objects.equals(ans.getStatus(), PostStatus.ACCEPTED)).toList();
if (acceptedAnswer.size() != 1) {
  log.error("Invalid accepted answers for a closed question {}", question.getId());
}

<@&987246399047479336> please have a look, thanks.

[storm grove]

.findAny().orElseThrow() or .findFirst().orElseThrow()

Also if PostStatus.ACCEPTED can't be null, you can use ans -> PostStatus.ACCEPTED.equals(ans.getStatus())
And if PostStatus is an enum, you can do ans -> PostStatus.ACCEPTED == ans.getStatus()

[vernal vine]

k

[vernal vine]

also does this handle case where returned value can be a list (ie >1 values)

[storm grove]

it ignores it
and if it is 0 values, it throws a runtime exception

[vernal vine]

hm, but i am confused do i need to check for multiple values, as this is the only method to change post status and it does not allow mutiple accepted answers

[storm grove]

It will ignore them

findFirst will take the first value

findAny will usually take the first value but can technically can take any value

[vernal vine]

ya got that part but if there does exist >1 values it is a problem

[storm grove]

as I said, it will take the first value and ignore the rest

[vernal vine]

i dont think u understand my doubt but anyway thank for the help

[storm grove]

what it is then ?

You ask what if there is more than 1 value, I answered that it will ignore them

[vernal vine]

like it should not have >1 accepted answer, it is not about if it return 1 value

[storm grove]

wdym

[vernal vine]

i will explain in 5 min

[regal knoll]

I uploaded your attachments as Gist. This makes them more accessible, for example to mobile users.

[vernal vine]

so this is the current logic to handle answer status change

an answer can only have unreviewed, accepted as their status

so when user tries to change status of an answer (unreviewed by default), following cases are possible:
-> (new operation) if current question status is not CLOSED, it will accept current answer as ACCEPTED
-> (remove operation) if current question status is CLOSED and current answer status is ACCEPTED, it will remove current answer as ACCEPTED and also reopen question (ie remove CLOSED)
-> (update operation) if current question status is CLOSED and current answer status is not ACCEPTED, it will remove prev answer as ACCEPTED, mark current answer as ACCEPTED

for the update operation, i want ACCEPTED answer (prev answer) from list of answer of question, that is y i am performing stream operation

the list of answer should not have multiple accepted answers, how do i make sure of it

@storm grove

[storm grove]

either you collect to a list like you did
or you use 2 streams

[vernal vine]

y two streams?

[storm grove]

 if(question.getAnswers().stream()
                    .filter(ans -> Objects.equals(ans.getStatus(), PostStatus.ACCEPTED))
                    .count() != 1) {
  log.error("Invalid accepted answers for a closed question {}", question.getId()); 
}
Post post = question.getAnswers().stream()
                    .filter(ans -> Objects.equals(ans.getStatus(), PostStatus.ACCEPTED))
                    .findAny().orElseThrow();

But well

just keep your apprach

[vernal vine]

k thx

also do u understand my code (ie what it does)?

[storm grove]

Yes, I check it quickly

[vernal vine]

k, had a question related to it but already solved