WorkerMethod.java

HashMap<String,PedestalledLeanLinkedList<BooleanContradictableType>> requestsInProgress = new HashMap<>();

protected synchronized void likeDislike(String id, boolean _desiredLikeState, boolean chain) {
    PedestalledLeanLinkedList<BooleanContradictableType> currentLinkedList = requestsInProgress.get(id);
    if (chain && currentLinkedList != null) {
        currentLinkedList.poll();/* Previous like state request */
        if (currentLinkedList.isEmpty()) {
            requestsInProgress.remove(id);
            return;
        }
    } else {
        if (currentLinkedList == null) {
            currentLinkedList = new PedestalledLeanLinkedList<>();
            currentLinkedList.insert(new BooleanContradictableType(_desiredLikeState));
            requestsInProgress.put(id, currentLinkedList);
        } else {
            BooleanContradictableType type = currentLinkedList.peek();
            if (type != null && type.getValue() == _desiredLikeState) {
                return;
            }
            currentLinkedList.insert(new BooleanContradictableType(_desiredLikeState));
        }
    }

    BooleanContradictableType type = currentLinkedList.peek();
    boolean desiredLikeState = type.getValue();
    executors.networkIO().execute(() -> {
        Runnable keepTheChainGoing = () -> likeDislike(id, desiredLikeState, true);

        final Response currentForLike = sourceOfTruth.find(id);
        if (currentForLike.isLiked() == desiredLikeState) {
            keepTheChainGoing.run();
            return;
        }

        currentForLike.setLiked(desiredLikeState);
        currentForLike.setLikes(desiredLikeState ? currentForLike.getLikes() + 1 : currentForLike.getLikes() - 1);
        sourceOfTruth.update(currentForLike);

        ResponseBodyCallbackAdapter callbackAdapter = new ResponseBodyCallbackAdapter<>(new ResponseBodyCallbackAdapter.SimpleCallback<Void>() {

            @Override
            public void onSuccessfulResponse(Void response) {
                sourceOfTruth.update(currentForLike);
            }

            @Override
            public void onNoSuccess() {
                revertLikeDislike();
            }

            @Override
            public void onPostEverytime() {
                keepTheChainGoing.run();
            }

            private void revertLikeDislike() {
                if (desiredLikeState) {
                    currentForLike.dislike();
                } else {
                    currentForLike.like();
                }

                sourceOfTruth.update(currentForLike);
            }
        });

        Call<ResponseBody<Void>> call = desiredLikeState ?
                apiCalls.like(id) : apiCalls.unlike(id);

        call.enqueue(callbackAdapter);
    });
}