How to create custom tasks for Firebase using the Google Play services Task API

Question

I\'d like to create custom tasks like these ones in firebase in order to chain my API async calls. How can I achieve that?

Answer 1

Suppose you have a Document class, you could do as follow:

Create successfuly resolved task

Tasks.forResult(document);

Create a failed task

Tasks.forException(new RuntimeException("Cool message"));

Create from Callable

interface CreateDocument extends Callable {
    @Override
    Document call();
}
Tasks.call(new CreateDocument());

Create using task completion source

Task createDocument() {
    TaskCompletionSource tcs = new TaskCompletionSource();
    if (this.someThingGoesWrong()) {
        tcs.setException(new RuntimeException("Cooler message"));
    } else {
        tcs.setResult(Document.factory());
    }

    tcs.getTask();
}