java/dagger/internal/AbstractMapFactory.java

/*
 * Copyright (C) 2014 The Dagger Authors.
 *
 * 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 dagger.internal;

import static dagger.internal.DaggerCollections.newLinkedHashMapWithExpectedSize;
import static dagger.internal.Preconditions.checkNotNull;
import static java.util.Collections.unmodifiableMap;

import java.util.LinkedHashMap;
import java.util.Map;
import javax.inject.Provider;

/**
 * An {@code abstract} {@link Factory} implementation used to implement {@link Map} bindings.
 *
 * @param <K> the key type of the map that this provides
 * @param <V> the type that each contributing factory
 * @param <V2> the value type of the map that this provides
 */
abstract class AbstractMapFactory<K, V, V2> implements Factory<Map<K, V2>> {
  private final Map<K, Provider<V>> contributingMap;

  AbstractMapFactory(Map<K, Provider<V>> map) {
    this.contributingMap = unmodifiableMap(map);
  }

  /** The map of {@link Provider}s that contribute to this map binding. */
  final Map<K, Provider<V>> contributingMap() {
    return contributingMap;
  }

  /** A builder for {@link AbstractMapFactory}. */
  public abstract static class Builder<K, V, V2> {
    final LinkedHashMap<K, Provider<V>> map;

    Builder(int size) {
      this.map = newLinkedHashMapWithExpectedSize(size);
    }

    // Unfortunately, we cannot return a self-type here because a raw Provider type passed to one of
    // these methods affects the returned type of the method. The first put*() call erases the self
    // type to the "raw" self type, and the second erases the type to the upper bound
    // (AbstractMapFactory.Builder), which doesn't have a build() method.
    //
    // The methods are therefore not declared public so that each subtype will redeclare them and
    // expand their accessibility

    /** Associates {@code key} with {@code providerOfValue}. */
    Builder<K, V, V2> put(K key, Provider<V> providerOfValue) {
      map.put(checkNotNull(key, "key"), checkNotNull(providerOfValue, "provider"));
      return this;
    }

    Builder<K, V, V2> putAll(Provider<Map<K, V2>> mapOfProviders) {
      if (mapOfProviders instanceof DelegateFactory) {
        @SuppressWarnings("unchecked")
        DelegateFactory<Map<K, V2>> asDelegateFactory = (DelegateFactory) mapOfProviders;
        return putAll(asDelegateFactory.getDelegate());
      }
      @SuppressWarnings("unchecked")
      AbstractMapFactory<K, V, ?> asAbstractMapFactory =
          ((AbstractMapFactory<K, V, ?>) (Provider) mapOfProviders);
      map.putAll(asAbstractMapFactory.contributingMap);
      return this;
    }
  }
}