A Session Manager Class.

SessionManager.java

import java.util.function.Function;

import rx.Completable;
import rx.Observable;
import rx.functions.Func1;

public class Session<T> {
	public static interface CheckedFunc0<R> {
		public R call() throws Exception;
	}

	public static interface CheckedAction1<T> {
		public void call(T t) throws Exception;
	}

	private CheckedFunc0<T> resourceFactory;
	private CheckedAction1<? super T> disposeAction;

	public Session(final CheckedFunc0<T> resourceFactory, final CheckedAction1<? super T> disposeAction) {
		this.resourceFactory = resourceFactory;
		this.disposeAction = disposeAction;
	}

	public final Completable checkoutWriteOnly(final Function<? super T, Completable> func) {
		return checkoutReadWrite(t -> func.apply(t).toObservable()).toCompletable();
	}

	public final <R> Observable<R> checkoutReadWrite(final Func1<? super T, ? extends Observable<? extends R>> func) {
		return Observable.using(() -> {
			try {
				return resourceFactory.call();
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		} , func, (rsrc) -> {
			try {
				disposeAction.call(rsrc);
			} catch (Exception e) {
				throw new RuntimeException(e);
			}
		});
	}
}

If I may ask, Where do one get the "rx" Package