Using Filter operator in Reactor Java

Question

I am trying to filter out the name which are not present in DB results. It's not working

Data Present in Db:

  A,B,C,D

Payload Contains:

C,D,E,X

Expected Result:

E,X

Below is the code snippet.

     public void filterName(Flux<String> payloadList)
          {
           nameRepo.findAll() <-- DB call which is reactiverepository
           .map(dbObj->dbObj.getName())                
           .collectList().flatMapMany(Mono::just)
           .map(dbNameList->payloadList.filter(name-> 
           !dbNameList.contains(name)).subscribe())
          .subscribe(z-> System.out.println(z));;   
    }

In result I am getting LambdaSubscriber object.

Answer 1

The method collectList returns a Mono<List<String>> that can be transformed to Flux. Therefore, using flatMapMany it becomes payloadList filtering out the dbNameList.

public void filterName(Flux<String> payloadList) {
    nameRepo.findAll() < --DB call which is reactive repository
        .map(dbObj -> dbObj.getName())
        .collectList()
        .flatMapMany(dbNameList -> payloadList.filter(name -> !dbNameList.contains(name)))
        .subscribe(System.out::println);
}