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Merge pull request #18 from thomasnield/master
GuavaTransformers
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‎src/main/java/rx/transformer/GuavaTransformers.java

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package rx.transformer;
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import com.google.common.collect.ImmutableList;
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import com.google.common.collect.ImmutableListMultimap;
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import com.google.common.collect.ImmutableMap;
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import com.google.common.collect.ImmutableSet;
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import rx.Observable;
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import rx.functions.Action2;
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import rx.functions.Func0;
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import rx.functions.Func1;
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/**
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* Copyright 2014 Netflix, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* A class of static factory methods to transform an Observable into an Observable of Guauva collections
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*/
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public final class GuavaTransformers {
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private GuavaTransformers() {}
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/**
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* Returns a Transformer<T,ImmutableList<T>&gt that maps an Observable<T> to an Observable<ImmutableList<T>>
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*/
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public static <T> Observable.Transformer<T,ImmutableList<T>> toImmutableList() {
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return new Observable.Transformer<T, ImmutableList<T>>() {
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@Override
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public Observable<ImmutableList<T>> call(Observable<T> source) {
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return source.collect(new Func0<ImmutableList.Builder<T>>() {
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@Override
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public ImmutableList.Builder<T> call() {
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return ImmutableList.builder();
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}
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}, new Action2<ImmutableList.Builder<T>, T>() {
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@Override
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public void call(ImmutableList.Builder<T> builder, T t) {
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builder.add(t);
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}
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})
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.map(new Func1<ImmutableList.Builder<T>, ImmutableList<T>>() {
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@Override
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public ImmutableList<T> call(ImmutableList.Builder<T> builder) {
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return builder.build();
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}
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});
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}
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};
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}
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/**
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* Returns a Transformer&lt;T,ImmutableSet&lt;T&gt;&gt that maps an Observable&lt;T&gt; to an Observable&lt;ImmutableSet&lt;T&gt;&gt;
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*/
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public static <T> Observable.Transformer<T,ImmutableSet<T>> toImmutableSet() {
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return new Observable.Transformer<T, ImmutableSet<T>>() {
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@Override
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public Observable<ImmutableSet<T>> call(Observable<T> source) {
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return source.collect(new Func0<ImmutableSet.Builder<T>>() {
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@Override
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public ImmutableSet.Builder<T> call() {
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return ImmutableSet.builder();
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}
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}, new Action2<ImmutableSet.Builder<T>, T>() {
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@Override
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public void call(ImmutableSet.Builder<T> builder, T t) {
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builder.add(t);
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}
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})
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.map(new Func1<ImmutableSet.Builder<T>, ImmutableSet<T>>() {
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@Override
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public ImmutableSet<T> call(ImmutableSet.Builder<T> builder) {
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return builder.build();
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}
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});
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}
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};
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}
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/**
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* Returns a Transformer&lt;T,ImmutableMap&lt;K,V&gt;&gt that maps an Observable&lt;T&gt; to an Observable&lt;ImmutableMap&lt;K,V&gt;&gt><br><br>
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* with a given Func1&lt;T,K&gt; keyMapper and Func1&lt;T,V&gt; valueMapper
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*/
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public static <T,K,V> Observable.Transformer<T,ImmutableMap<K,V>> toImmutableMap(final Func1<T,K> keyMapper, final Func1<T,V> valueMapper) {
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return new Observable.Transformer<T,ImmutableMap<K,V>>() {
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@Override
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public Observable<ImmutableMap<K, V>> call(Observable<T> observable) {
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return observable.collect(new Func0<ImmutableMap.Builder<K, V>>() {
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@Override
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public ImmutableMap.Builder<K, V> call() {
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return ImmutableMap.builder();
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}
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}, new Action2<ImmutableMap.Builder<K, V>, T>() {
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@Override
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public void call(ImmutableMap.Builder<K, V> builder, T t) {
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builder.put(keyMapper.call(t), valueMapper.call(t));
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}
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})
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.map(new Func1<ImmutableMap.Builder<K, V>, ImmutableMap<K, V>>() {
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@Override
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public ImmutableMap<K, V> call(ImmutableMap.Builder<K, V> builder) {
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return builder.build();
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}
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});
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}
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};
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}
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/**
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* Returns a Transformer&lt;T,ImmutableListMultimap&lt;K,V&gt;&gt that maps an Observable&lt;T&gt; to an Observable&lt;ImmutableListMultimap&lt;K,V&gt;&gt><br><br>
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* with a given Func1&lt;T,K&gt; keyMapper and Func1&lt;T,V&gt; valueMapper
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*/
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public static <T,K,V> Observable.Transformer<T,ImmutableListMultimap<K,V>> toImmutableListMultimap(final Func1<T,K> keyMapper, final Func1<T,V> valueMapper) {
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return new Observable.Transformer<T,ImmutableListMultimap<K,V>>() {
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@Override
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public Observable<ImmutableListMultimap<K, V>> call(Observable<T> observable) {
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return observable.collect(new Func0<ImmutableListMultimap.Builder<K, V>>() {
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@Override
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public ImmutableListMultimap.Builder<K, V> call() {
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return ImmutableListMultimap.builder();
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}
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}, new Action2<ImmutableListMultimap.Builder<K, V>, T>() {
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@Override
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public void call(ImmutableListMultimap.Builder<K, V> builder, T t) {
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builder.put(keyMapper.call(t), valueMapper.call(t));
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}
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})
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.map(new Func1<ImmutableListMultimap.Builder<K, V>, ImmutableListMultimap<K, V>>() {
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@Override
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public ImmutableListMultimap<K, V> call(ImmutableListMultimap.Builder<K, V> builder) {
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return builder.build();
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}
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});
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}
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};
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}
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}

‎src/test/java/rx/transformer/GuavaTransformersTest.java

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package rx.transformer;
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import static org.junit.Assert.*;
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import com.google.common.collect.ImmutableList;
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import com.google.common.collect.ImmutableListMultimap;
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import com.google.common.collect.ImmutableMap;
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import com.google.common.collect.ImmutableSet;
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import org.junit.Test;
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import rx.Observable;
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import rx.functions.Func1;
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public class GuavaTransformersTest {
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@Test
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public void testList() {
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assertEquals(ImmutableList.builder().add(1).add(3).add(2).add(3).build(), Observable.just(1, 3, 2, 3).compose(GuavaTransformers.toImmutableList()).toBlocking().last());
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}
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@Test
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public void testSet() {
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assertEquals(ImmutableSet.builder().add(1).add(3).add(2).add(3).build(), Observable.just(1, 3, 2, 3).compose(GuavaTransformers.toImmutableSet()).toBlocking().last());
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}
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Func1<String, String> keyMapper = new Func1<String, String>() {
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@Override
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public String call(String t) {
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return t.split(":")[0];
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}
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};
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Func1<String, String> valueMapper = new Func1<String, String>() {
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@Override
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public String call(String t) {
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return t.split(":")[1];
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}
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};
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@Test
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public void testMap() {
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assertEquals(ImmutableMap.builder().put("a", "1").put("b", "2").put("c", "3").build(), Observable.just("a:1", "b:2", "c:3").compose(GuavaTransformers.toImmutableMap(keyMapper, valueMapper))
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.toBlocking().last());
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}
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@Test
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public void testListMap() {
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assertEquals(ImmutableListMultimap.builder().put("a", "1").putAll("b", "2", "4").put("c", "3").build(), Observable.just("a:1", "b:2", "c:3", "b:4").compose(
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GuavaTransformers.toImmutableListMultimap(keyMapper, valueMapper)).toBlocking().last());
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}
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}

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