How to convert asynchronous call to synchronous for firebase access Amazon web service Lambda function in java

Question

I want to call a AWS lambda function within which I am connecting to a Firebase database. The problem is that the handler executes before I get the needed data from Firebase.

Answer 1

A recipe to convert an asynchronous call into a synchronous one:

Let's assume the async call is called fooAsync(), and that you have some way to check a result condition when the operation is completed. You can introduce your own volatile boolean fooComplete to track this.

Then:

public void fooSyncWrapper() {
    volatile boolean fooComplete = false;

    Thread thread = new Thread() {
        @Override
        public void run() {
            fooAsync();

            while (!fooComplete) {
                // busy wait on completion condition
                fooComplete = checkIfComplete();
            }

            // task is completed, thread will join
        }
    };

    thread.start();
    thread.join();
}