1 /* 2 * Copyright (C) 2014 Google, Inc. 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 package dagger.internal; 17 18 import java.util.Map; 19 import java.util.Map.Entry; 20 import javax.inject.Provider; 21 22 import static dagger.internal.Collections.newLinkedHashMapWithExpectedSize; 23 import static java.util.Collections.unmodifiableMap; 24 25 /** 26 * A {@link Factory} implementation used to implement {@link Map} bindings. This factory returns a 27 * {@code Map<K, V>} when calling {@link #get} (as specified by {@link Factory}). 28 * 29 * @author Chenying Hou 30 * @since 2.0 31 * 32 */ 33 public final class MapFactory<K, V> implements Factory<Map<K, V>> { 34 private final Map<K, Provider<V>> contributingMap; 35 36 private MapFactory(Map<K, Provider<V>> map) { 37 this.contributingMap = unmodifiableMap(map); 38 } 39 40 /** 41 * Returns a new MapFactory. 42 */ 43 public static <K, V> MapFactory<K, V> create(Provider<Map<K, Provider<V>>> mapProviderFactory) { 44 Map<K, Provider<V>> map = mapProviderFactory.get(); 45 return new MapFactory<K, V>(map); 46 } 47 48 /** 49 * Returns a {@code Map<K, V>} whose iteration order is that of the elements 50 * given by each of the providers, which are invoked in the order given at creation. 51 */ 52 @Override 53 public Map<K, V> get() { 54 Map<K, V> result = newLinkedHashMapWithExpectedSize(contributingMap.size()); 55 for (Entry<K, Provider<V>> entry: contributingMap.entrySet()) { 56 result.put(entry.getKey(), entry.getValue().get()); 57 } 58 return unmodifiableMap(result); 59 } 60 } 61
