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/**

* 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.from(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> from(new HorrorMovie());

Func2<Movie, Movie, Movie> chooseSecondMovie =

new Func2<Movie, Movie, Movie>() {

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/Netflix/RxJava/issues/360#issuecomment-24203016

*/

@SuppressWarnings("unused")

@Test

public void reduceWithCovariantObjects() {

Observable<Movie> horrorMovies = Observable.<Movie> from(new HorrorMovie());

Func2<Movie, Movie, Movie> chooseSecondMovie =

new Func2<Movie, Movie, Movie>() {

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/Netflix/RxJava/issues/360#issuecomment-24203016

*/

@Test

public void reduceCovariance() {

// must type it to <Movie>

Observable<Movie> horrorMovies = Observable.<Movie> from(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>() {

public Movie call(Movie t1, Movie t2) {

return t2;

}

};

obs.reduce(chooseSecondMovie);

}

}