1 /* 2 * Copyright (C) 2016 The Dagger Authors. 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package dagger.producers.internal; 18 19 import static com.google.common.util.concurrent.Futures.transform; 20 import static com.google.common.util.concurrent.MoreExecutors.directExecutor; 21 22 import com.google.common.base.Function; 23 import com.google.common.collect.ImmutableMap; 24 import com.google.common.collect.Iterables; 25 import com.google.common.collect.Maps; 26 import com.google.common.util.concurrent.Futures; 27 import com.google.common.util.concurrent.ListenableFuture; 28 import dagger.producers.Produced; 29 import dagger.producers.Producer; 30 import java.util.List; 31 import java.util.Map; 32 import javax.inject.Provider; 33 34 /** 35 * A {@link Producer} implementation used to implement {@link Map} bindings. This producer returns a 36 * {@code Map<K, Produced<V>>} which is populated by calls to the delegate {@link Producer#get} 37 * methods. 38 */ 39 public final class MapOfProducedProducer<K, V> extends AbstractMapProducer<K, V, Produced<V>> { MapOfProducedProducer(ImmutableMap<K, Producer<V>> contributingMap)40 private MapOfProducedProducer(ImmutableMap<K, Producer<V>> contributingMap) { 41 super(contributingMap); 42 } 43 44 @Override compute()45 public ListenableFuture<Map<K, Produced<V>>> compute() { 46 return Futures.transform( 47 Futures.allAsList( 48 Iterables.transform( 49 contributingMap().entrySet(), MapOfProducedProducer.<K, V>entryUnwrapper())), 50 new Function<List<Map.Entry<K, Produced<V>>>, Map<K, Produced<V>>>() { 51 @Override 52 public Map<K, Produced<V>> apply(List<Map.Entry<K, Produced<V>>> entries) { 53 return ImmutableMap.copyOf(entries); 54 } 55 }, 56 directExecutor()); 57 } 58 59 private static final Function< 60 Map.Entry<Object, Producer<Object>>, 61 ListenableFuture<Map.Entry<Object, Produced<Object>>>> 62 ENTRY_UNWRAPPER = 63 new Function< 64 Map.Entry<Object, Producer<Object>>, 65 ListenableFuture<Map.Entry<Object, Produced<Object>>>>() { 66 @Override 67 public ListenableFuture<Map.Entry<Object, Produced<Object>>> apply( 68 final Map.Entry<Object, Producer<Object>> entry) { 69 return transform( 70 Producers.createFutureProduced(entry.getValue().get()), 71 new Function<Produced<Object>, Map.Entry<Object, Produced<Object>>>() { 72 @Override 73 public Map.Entry<Object, Produced<Object>> apply(Produced<Object> value) { 74 return Maps.immutableEntry(entry.getKey(), value); 75 } 76 }, 77 directExecutor()); 78 } 79 }; 80 81 @SuppressWarnings({"unchecked", "rawtypes"}) // bivariate implementation 82 private static <K, V> 83 Function<Map.Entry<K, Producer<V>>, ListenableFuture<Map.Entry<K, Produced<V>>>> 84 entryUnwrapper() { 85 return (Function) ENTRY_UNWRAPPER; 86 } 87 88 /** Returns a new {@link Builder}. */ 89 public static <K, V> Builder<K, V> builder(int size) { 90 return new Builder<>(size); 91 } 92 93 /** A builder for {@link MapOfProducedProducer}. */ 94 public static final class Builder<K, V> extends AbstractMapProducer.Builder<K, V, Produced<V>> { 95 private Builder(int size) { 96 super(size); 97 } 98 99 @Override 100 public Builder<K, V> put(K key, Producer<V> producerOfValue) { 101 super.put(key, producerOfValue); 102 return this; 103 } 104 105 @Override 106 public Builder<K, V> put(K key, Provider<V> providerOfValue) { 107 super.put(key, providerOfValue); 108 return this; 109 } 110 111 @Override 112 public Builder<K, V> putAll(Producer<Map<K, Produced<V>>> mapOfProducedProducer) { 113 super.putAll(mapOfProducedProducer); 114 return this; 115 } 116 117 /** Returns a new {@link MapOfProducedProducer}. */ 118 public MapOfProducedProducer<K, V> build() { 119 return new MapOfProducedProducer<>(mapBuilder.build()); 120 } 121 } 122 } 123