import org.androidannotations.api.sharedpreferences.AbstractPrefField;
import rx.Observable;
import rx.subjects.BehaviorSubject;

public class PreferenceObservable<T> {

    private AbstractPrefField prefField;
    private BehaviorSubject<T> prefSubject;

    public PreferenceObservable(AbstractPrefField pref) {
        prefField = pref;
        prefSubject = BehaviorSubject.create(getLast());
    }

    public Observable<T> get() {
        return prefSubject.asObservable();
    }

    @SuppressWarnings("unchecked")
    public T getLast() {
        try {
            return (T) prefField.getClass().getMethod("get").invoke(prefField);
        } catch (Exception e) {}
        return null;
    }

    public void put(T value) {
        try {
            for (Method m : prefField.getClass().getMethods())
                if (m.getName().equals("put")) {
                    m.invoke(prefField, value);
                    prefSubject.onNext(value);
                    break;
                }
        } catch (Exception e) {}
    }
}