Mis on Completable klassi roll ja eesmärk RxJava teegis?

In RxJava, the Completable class represents a type of Observable that does not emit any items, but only signals successful completion or an error.

Its main purpose is to represent operations that either complete successfully without a return value, or end with an error. This is useful for asynchronous tasks where the result is not important, only the fact of completion.

Example of using Completable:

Completable.fromAction(() -> {
    // Perform some operation, e.g., save data to database
    saveDataToDatabase();
})\.subscribe(() -> {
    // Handle successful completion
    System.out.println("Operation completed");
}, throwable -> {
    // Handle error
    throwable.printStackTrace();
});

This way, Completable helps to work conveniently with tasks where there is no need to return data, only to monitor the execution status.