1 /* 2 * Copyright (C) 2014 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.internal; 18 19 import static dagger.internal.DaggerCollections.newLinkedHashMapWithExpectedSize; 20 import static java.util.Collections.unmodifiableMap; 21 22 import java.util.Collections; 23 import java.util.Map; 24 import java.util.Map.Entry; 25 import javax.inject.Provider; 26 27 /** 28 * A {@link Factory} implementation used to implement {@link Map} bindings. This factory returns a 29 * {@code Map<K, V>} when calling {@link #get} (as specified by {@link Factory}). 30 */ 31 public final class MapFactory<K, V> extends AbstractMapFactory<K, V, V> { 32 private static final Provider<Map<Object, Object>> EMPTY = 33 InstanceFactory.create(Collections.emptyMap()); 34 35 /** Returns a new {@link Builder} */ builder(int size)36 public static <K, V> Builder<K, V> builder(int size) { 37 return new Builder<>(size); 38 } 39 40 /** Returns a factory of an empty map. */ 41 @SuppressWarnings("unchecked") // safe contravariant cast emptyMapProvider()42 public static <K, V> Provider<Map<K, V>> emptyMapProvider() { 43 return (Provider<Map<K, V>>) (Provider) EMPTY; 44 } 45 MapFactory(Map<K, Provider<V>> map)46 private MapFactory(Map<K, Provider<V>> map) { 47 super(map); 48 } 49 50 /** 51 * Returns a {@code Map<K, V>} whose iteration order is that of the elements given by each of the 52 * providers, which are invoked in the order given at creation. 53 */ 54 @Override get()55 public Map<K, V> get() { 56 Map<K, V> result = newLinkedHashMapWithExpectedSize(contributingMap().size()); 57 for (Entry<K, Provider<V>> entry : contributingMap().entrySet()) { 58 result.put(entry.getKey(), entry.getValue().get()); 59 } 60 return unmodifiableMap(result); 61 } 62 63 /** A builder for {@link MapFactory}. */ 64 public static final class Builder<K, V> extends AbstractMapFactory.Builder<K, V, V> { Builder(int size)65 private Builder(int size) { 66 super(size); 67 } 68 69 @Override put(K key, Provider<V> providerOfValue)70 public Builder<K, V> put(K key, Provider<V> providerOfValue) { 71 super.put(key, providerOfValue); 72 return this; 73 } 74 75 @Override putAll(Provider<Map<K, V>> mapFactory)76 public Builder<K, V> putAll(Provider<Map<K, V>> mapFactory) { 77 super.putAll(mapFactory); 78 return this; 79 } 80 81 /** Returns a new {@link MapProviderFactory}. */ build()82 public MapFactory<K, V> build() { 83 return new MapFactory<>(map); 84 } 85 } 86 } 87