techyourchance

public abstract class BaseBusyObservable<LISTENER_CLASS> extends BaseObservable<LISTENER_CLASS> {

    private final AtomicBoolean mIsBusy = new AtomicBoolean(false);

    public final boolean isBusy() {
        return mIsBusy.get();
    }

    /**
     * Atomically assert not busy and become busy

techyourchance

public abstract class BaseObservable<LISTENER_CLASS> {

    private final Object MONITOR = new Object();

    private final Set<LISTENER_CLASS> mListeners = new HashSet<>();

    public void registerListener(LISTENER_CLASS listener) {
        synchronized (MONITOR) {
            boolean hadNoListeners = mListeners.size() == 0;
            mListeners.add(listener);