/**
* Copyright 2014 Netflix, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package rx;
import static org.junit.Assert.assertEquals;
import org.junit.Test;
import rx.CovarianceTest.HorrorMovie;
import rx.CovarianceTest.Movie;
import rx.functions.Func2;
public class ReduceTests {
@Test
public void reduceInts() {
Observable<Integer> o = Observable.just(1, 2, 3);
int value = o.reduce(new Func2<Integer, Integer, Integer>() {
@Override
public Integer call(Integer t1, Integer t2) {
return t1 + t2;
}
}).toBlocking().single();
assertEquals(6, value);
}
@SuppressWarnings("unused")
@Test
public void reduceWithObjects() {
Observable<Movie> horrorMovies = Observable.<Movie> just(new HorrorMovie());
Func2<Movie, Movie, Movie> chooseSecondMovie =
new Func2<Movie, Movie, Movie>() {
@Override
public Movie call(Movie t1, Movie t2) {
return t2;
}
};
Observable<Movie> reduceResult = horrorMovies.scan(chooseSecondMovie).takeLast(1);
Observable<Movie> reduceResult2 = horrorMovies.reduce(chooseSecondMovie);
}
/**
* Reduce consumes and produces T so can't do covariance.
*
* https://github.com/ReactiveX/RxJava/issues/360#issuecomment-24203016
*/
@SuppressWarnings("unused")
@Test
public void reduceWithCovariantObjects() {
Observable<Movie> horrorMovies = Observable.<Movie> just(new HorrorMovie());
Func2<Movie, Movie, Movie> chooseSecondMovie =
new Func2<Movie, Movie, Movie>() {
@Override
public Movie call(Movie t1, Movie t2) {
return t2;
}
};
Observable<Movie> reduceResult2 = horrorMovies.reduce(chooseSecondMovie);
}
/**
* Reduce consumes and produces T so can't do covariance.
*
* https://github.com/ReactiveX/RxJava/issues/360#issuecomment-24203016
*/
@Test
public void reduceCovariance() {
// must type it to <Movie>
Observable<Movie> horrorMovies = Observable.<Movie> just(new HorrorMovie());
libraryFunctionActingOnMovieObservables(horrorMovies);
}
/*
* This accepts <Movie> instead of <? super Movie> since `reduce` can't handle covariants
*/
public void libraryFunctionActingOnMovieObservables(Observable<Movie> obs) {
Func2<Movie, Movie, Movie> chooseSecondMovie =
new Func2<Movie, Movie, Movie>() {
@Override
public Movie call(Movie t1, Movie t2) {
return t2;
}
};
obs.reduce(chooseSecondMovie);
}
}