package com.google.inject.internal;

import static com.google.inject.internal.Element.Type.MAPBINDER;
import static com.google.inject.internal.Errors.checkConfiguration;
import static com.google.inject.internal.Errors.checkNotNull;
import static com.google.inject.internal.RealMultibinder.setOf;
import static com.google.inject.util.Types.newParameterizedType;
import static com.google.inject.util.Types.newParameterizedTypeWithOwner;

import com.google.common.base.Objects;
import com.google.common.base.Preconditions;
import com.google.common.collect.HashMultimap;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableMultimap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.LinkedHashMultimap;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Multimap;
import com.google.common.collect.Sets;
import com.google.inject.Binder;
import com.google.inject.Binding;
import com.google.inject.Injector;
import com.google.inject.Key;
import com.google.inject.Module;
import com.google.inject.Provider;
import com.google.inject.TypeLiteral;
import com.google.inject.binder.LinkedBindingBuilder;
import com.google.inject.internal.InternalProviderInstanceBindingImpl.InitializationTiming;
import com.google.inject.multibindings.MapBinderBinding;
import com.google.inject.multibindings.Multibinder;
import com.google.inject.multibindings.MultibindingsTargetVisitor;
import com.google.inject.spi.BindingTargetVisitor;
import com.google.inject.spi.Dependency;
import com.google.inject.spi.Element;
import com.google.inject.spi.ProviderInstanceBinding;
import com.google.inject.spi.ProviderWithExtensionVisitor;
import com.google.inject.util.Types;
import java.lang.annotation.Annotation;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

The actual mapbinder plays several roles:
As a MapBinder, it acts as a factory for LinkedBindingBuilders for each of the map's values. It delegates to a Multibinder of entries (keys to value providers). 
As a Module, it installs the binding to the map itself, as well as to a corresponding map
whose values are providers.
As a module, this implements equals() and hashcode() in order to trick Guice into executing
its configure() method only once. That makes it so that multiple mapbinders can be created for
the same target map, but only one is bound. Since the list of bindings is retrieved from the
injector itself (and not the mapbinder), each mapbinder has access to all contributions from all
equivalent mapbinders.
Rather than binding a single Map.Entry<K, V>, the map binder binds keys and values
independently. This allows the values to be properly scoped.
/**
 * The actual mapbinder plays several roles:
 *
 * <p>As a MapBinder, it acts as a factory for LinkedBindingBuilders for each of the map's values.
 * It delegates to a {@link Multibinder} of entries (keys to value providers).
 *
 * <p>As a Module, it installs the binding to the map itself, as well as to a corresponding map
 * whose values are providers.
 *
 * <p>As a module, this implements equals() and hashcode() in order to trick Guice into executing
 * its configure() method only once. That makes it so that multiple mapbinders can be created for
 * the same target map, but only one is bound. Since the list of bindings is retrieved from the
 * injector itself (and not the mapbinder), each mapbinder has access to all contributions from all
 * equivalent mapbinders.
 *
 * <p>Rather than binding a single Map.Entry&lt;K, V&gt;, the map binder binds keys and values
 * independently. This allows the values to be properly scoped.
 */
public final class RealMapBinder<K, V> implements Module {

  
Returns a new mapbinder that collects entries of keyType/valueType in a Map that is itself bound with no binding annotation. /**
   * Returns a new mapbinder that collects entries of {@code keyType}/{@code valueType} in a {@link
   * Map} that is itself bound with no binding annotation.
   */
  public static <K, V> RealMapBinder<K, V> newMapRealBinder(
      Binder binder, TypeLiteral<K> keyType, TypeLiteral<V> valueType) {
    binder = binder.skipSources(RealMapBinder.class);
    return newRealMapBinder(
        binder,
        keyType,
        valueType,
        Key.get(mapOf(keyType, valueType)),
        RealMultibinder.newRealSetBinder(binder, Key.get(entryOfProviderOf(keyType, valueType))));
  }

  
Returns a new mapbinder that collects entries of keyType/valueType in a Map that is itself bound with annotation. /**
   * Returns a new mapbinder that collects entries of {@code keyType}/{@code valueType} in a {@link
   * Map} that is itself bound with {@code annotation}.
   */
  public static <K, V> RealMapBinder<K, V> newRealMapBinder(
      Binder binder, TypeLiteral<K> keyType, TypeLiteral<V> valueType, Annotation annotation) {
    binder = binder.skipSources(RealMapBinder.class);
    return newRealMapBinder(
        binder,
        keyType,
        valueType,
        Key.get(mapOf(keyType, valueType), annotation),
        RealMultibinder.newRealSetBinder(
            binder, Key.get(entryOfProviderOf(keyType, valueType), annotation)));
  }

  
Returns a new mapbinder that collects entries of keyType/valueType in a Map that is itself bound with annotationType. /**
   * Returns a new mapbinder that collects entries of {@code keyType}/{@code valueType} in a {@link
   * Map} that is itself bound with {@code annotationType}.
   */
  public static <K, V> RealMapBinder<K, V> newRealMapBinder(
      Binder binder,
      TypeLiteral<K> keyType,
      TypeLiteral<V> valueType,
      Class<? extends Annotation> annotationType) {
    binder = binder.skipSources(RealMapBinder.class);
    return newRealMapBinder(
        binder,
        keyType,
        valueType,
        Key.get(mapOf(keyType, valueType), annotationType),
        RealMultibinder.newRealSetBinder(
            binder, Key.get(entryOfProviderOf(keyType, valueType), annotationType)));
  }

  @SuppressWarnings("unchecked") // a map of <K, V> is safely a Map<K, V>
  static <K, V> TypeLiteral<Map<K, V>> mapOf(TypeLiteral<K> keyType, TypeLiteral<V> valueType) {
    return (TypeLiteral<Map<K, V>>)
        TypeLiteral.get(Types.mapOf(keyType.getType(), valueType.getType()));
  }

  @SuppressWarnings("unchecked") // a provider map <K, V> is safely a Map<K, Provider<V>>
  static <K, V> TypeLiteral<Map<K, Provider<V>>> mapOfProviderOf(
      TypeLiteral<K> keyType, TypeLiteral<V> valueType) {
    return (TypeLiteral<Map<K, Provider<V>>>)
        TypeLiteral.get(Types.mapOf(keyType.getType(), Types.providerOf(valueType.getType())));
  }

  // provider map <K, V> is safely a Map<K, javax.inject.Provider<V>>>
  @SuppressWarnings("unchecked")
  static <K, V> TypeLiteral<Map<K, javax.inject.Provider<V>>> mapOfJavaxProviderOf(
      TypeLiteral<K> keyType, TypeLiteral<V> valueType) {
    return (TypeLiteral<Map<K, javax.inject.Provider<V>>>)
        TypeLiteral.get(
            Types.mapOf(
                keyType.getType(),
                newParameterizedType(javax.inject.Provider.class, valueType.getType())));
  }

  @SuppressWarnings("unchecked") // a provider map <K, Set<V>> is safely a Map<K, Set<Provider<V>>>
  static <K, V> TypeLiteral<Map<K, Set<Provider<V>>>> mapOfSetOfProviderOf(
      TypeLiteral<K> keyType, TypeLiteral<V> valueType) {
    return (TypeLiteral<Map<K, Set<Provider<V>>>>)
        TypeLiteral.get(
            Types.mapOf(keyType.getType(), Types.setOf(Types.providerOf(valueType.getType()))));
  }

  @SuppressWarnings("unchecked") // a provider map <K, Set<V>> is safely a Map<K, Set<Provider<V>>>
  static <K, V> TypeLiteral<Map<K, Set<javax.inject.Provider<V>>>> mapOfSetOfJavaxProviderOf(
      TypeLiteral<K> keyType, TypeLiteral<V> valueType) {
    return (TypeLiteral<Map<K, Set<javax.inject.Provider<V>>>>)
        TypeLiteral.get(
            Types.mapOf(
                keyType.getType(), Types.setOf(Types.javaxProviderOf(valueType.getType()))));
  }

  @SuppressWarnings("unchecked") // a provider map <K, Set<V>> is safely a Map<K, Set<Provider<V>>>
  static <K, V> TypeLiteral<Map<K, Collection<Provider<V>>>> mapOfCollectionOfProviderOf(
      TypeLiteral<K> keyType, TypeLiteral<V> valueType) {
    return (TypeLiteral<Map<K, Collection<Provider<V>>>>)
        TypeLiteral.get(
            Types.mapOf(
                keyType.getType(), Types.collectionOf(Types.providerOf(valueType.getType()))));
  }

  @SuppressWarnings("unchecked") // a provider map <K, Set<V>> is safely a Map<K, Set<Provider<V>>>
  static <K, V>
      TypeLiteral<Map<K, Collection<javax.inject.Provider<V>>>> mapOfCollectionOfJavaxProviderOf(
          TypeLiteral<K> keyType, TypeLiteral<V> valueType) {
    return (TypeLiteral<Map<K, Collection<javax.inject.Provider<V>>>>)
        TypeLiteral.get(
            Types.mapOf(
                keyType.getType(), Types.collectionOf(Types.javaxProviderOf(valueType.getType()))));
  }

  @SuppressWarnings("unchecked") // a provider entry <K, V> is safely a Map.Entry<K, Provider<V>>
  static <K, V> TypeLiteral<Map.Entry<K, Provider<V>>> entryOfProviderOf(
      TypeLiteral<K> keyType, TypeLiteral<V> valueType) {
    return (TypeLiteral<Map.Entry<K, Provider<V>>>)
        TypeLiteral.get(
            newParameterizedTypeWithOwner(
                Map.class,
                Map.Entry.class,
                keyType.getType(),
                Types.providerOf(valueType.getType())));
  }

  @SuppressWarnings("unchecked") // a provider entry <K, V> is safely a Map.Entry<K, Provider<V>>
  static <K, V> TypeLiteral<Map.Entry<K, Provider<V>>> entryOfJavaxProviderOf(
      TypeLiteral<K> keyType, TypeLiteral<V> valueType) {
    return (TypeLiteral<Map.Entry<K, Provider<V>>>)
        TypeLiteral.get(
            newParameterizedTypeWithOwner(
                Map.class,
                Map.Entry.class,
                keyType.getType(),
                Types.javaxProviderOf(valueType.getType())));
  }

  @SuppressWarnings("unchecked") // a provider entry <K, V> is safely a Map.Entry<K, Provider<V>>
  static <K, V>
      TypeLiteral<Set<Map.Entry<K, javax.inject.Provider<V>>>> setOfEntryOfJavaxProviderOf(
          TypeLiteral<K> keyType, TypeLiteral<V> valueType) {
    return (TypeLiteral<Set<Map.Entry<K, javax.inject.Provider<V>>>>)
        TypeLiteral.get(Types.setOf(entryOfJavaxProviderOf(keyType, valueType).getType()));
  }

  
Given a Key will return a Key> /** Given a Key<T> will return a Key<Provider<T>> */
  @SuppressWarnings("unchecked")
  private static <T> Key<Provider<T>> getKeyOfProvider(Key<T> valueKey) {
    return (Key<Provider<T>>)
        valueKey.ofType(Types.providerOf(valueKey.getTypeLiteral().getType()));
  }

  // Note: We use valueTypeAndAnnotation effectively as a Pair<TypeLiteral, Annotation|Class>
  // since it's an easy way to group a type and an optional annotation type or instance.
  static <K, V> RealMapBinder<K, V> newRealMapBinder(
      Binder binder, TypeLiteral<K> keyType, Key<V> valueTypeAndAnnotation) {
    binder = binder.skipSources(RealMapBinder.class);
    TypeLiteral<V> valueType = valueTypeAndAnnotation.getTypeLiteral();
    return newRealMapBinder(
        binder,
        keyType,
        valueType,
        valueTypeAndAnnotation.ofType(mapOf(keyType, valueType)),
        RealMultibinder.newRealSetBinder(
            binder, valueTypeAndAnnotation.ofType(entryOfProviderOf(keyType, valueType))));
  }

  private static <K, V> RealMapBinder<K, V> newRealMapBinder(
      Binder binder,
      TypeLiteral<K> keyType,
      TypeLiteral<V> valueType,
      Key<Map<K, V>> mapKey,
      RealMultibinder<Map.Entry<K, Provider<V>>> entrySetBinder) {
    RealMapBinder<K, V> mapBinder =
        new RealMapBinder<K, V>(binder, keyType, valueType, mapKey, entrySetBinder);
    binder.install(mapBinder);
    return mapBinder;
  }

  // Until the injector initializes us, we don't know what our dependencies are,
  // so initialize to the whole Injector.
  private static final ImmutableSet<Dependency<?>> MODULE_DEPENDENCIES =
      ImmutableSet.<Dependency<?>>of(Dependency.get(Key.get(Injector.class)));

  private final BindingSelection<K, V> bindingSelection;
  private final Binder binder;

  private final RealMultibinder<Map.Entry<K, Provider<V>>> entrySetBinder;

  private RealMapBinder(
      Binder binder,
      TypeLiteral<K> keyType,
      TypeLiteral<V> valueType,
      Key<Map<K, V>> mapKey,
      RealMultibinder<Map.Entry<K, Provider<V>>> entrySetBinder) {
    this.bindingSelection = new BindingSelection<>(keyType, valueType, mapKey, entrySetBinder);
    this.binder = binder;
    this.entrySetBinder = entrySetBinder;
  }

  public void permitDuplicates() {
    checkConfiguration(!bindingSelection.isInitialized(), "MapBinder was already initialized");
    entrySetBinder.permitDuplicates();
    binder.install(new MultimapBinder<K, V>(bindingSelection));
  }

  
Adds a binding to the map for the given key. /** Adds a binding to the map for the given key. */
  Key<V> getKeyForNewValue(K key) {
    checkNotNull(key, "key");
    checkConfiguration(!bindingSelection.isInitialized(), "MapBinder was already initialized");
    RealMultibinder<Map.Entry<K, Provider<V>>> entrySetBinder =
        bindingSelection.getEntrySetBinder();

    Key<V> valueKey =
        Key.get(
            bindingSelection.getValueType(),
            new RealElement(
                entrySetBinder.getSetName(), MAPBINDER, bindingSelection.getKeyType().toString()));
    entrySetBinder.addBinding().toProvider(new ProviderMapEntry<K, V>(key, valueKey));
    return valueKey;
  }

  
This creates two bindings. One for the Map.Entry<K, Provider<V>> and another for 
V. /**
   * This creates two bindings. One for the {@code Map.Entry<K, Provider<V>>} and another for {@code
   * V}.
   */
  public LinkedBindingBuilder<V> addBinding(K key) {
    return binder.bind(getKeyForNewValue(key));
  }

  @Override
  public void configure(Binder binder) {
    checkConfiguration(!bindingSelection.isInitialized(), "MapBinder was already initialized");

    // Binds a Map<K, Provider<V>>
    RealProviderMapProvider<K, V> providerMapProvider =
        new RealProviderMapProvider<K, V>(bindingSelection);
    binder.bind(bindingSelection.getProviderMapKey()).toProvider(providerMapProvider);

    // The map this exposes is internally an ImmutableMap, so it's OK to massage
    // the guice Provider to javax Provider in the value (since Guice provider
    // implements javax Provider).
    @SuppressWarnings({"unchecked", "rawtypes"})
    Provider<Map<K, javax.inject.Provider<V>>> javaxProviderMapProvider =
        (Provider) providerMapProvider;
    binder.bind(bindingSelection.getJavaxProviderMapKey()).toProvider(javaxProviderMapProvider);

    RealMapProvider<K, V> mapProvider = new RealMapProvider<>(bindingSelection);
    binder.bind(bindingSelection.getMapKey()).toProvider(mapProvider);

    // The Map.Entries are all ProviderMapEntry instances which do not allow setValue, so it is
    // safe to massage the return type like this
    @SuppressWarnings({"unchecked", "rawtypes"})
    Key<Set<Map.Entry<K, javax.inject.Provider<V>>>> massagedEntrySetProviderKey =
        (Key) bindingSelection.getEntrySetBinder().getSetKey();
    binder.bind(bindingSelection.getEntrySetJavaxProviderKey()).to(massagedEntrySetProviderKey);
  }

  @Override
  public boolean equals(Object o) {
    return o instanceof RealMapBinder
        && ((RealMapBinder<?, ?>) o).bindingSelection.equals(bindingSelection);
  }

  @Override
  public int hashCode() {
    return bindingSelection.hashCode();
  }

  
The BindingSelection contains some of the core state and logic for the MapBinder.
It lazily computes the value for keys for various permutations of Maps that are provided by this module. It also builds up maps from K to Binding<V>, which is used by all of the internal factories to actually provide the desired maps. 
During initialization time there is only one BindingSelection. It is possible that multiple different BindingSelections are constructed. Specifically, in the case of two different modules each adding bindings to the same MapBinder. If that happens, we define the BindingSelection held by the RealMapProvider to be the authoritative one. The logic for this exists in RealMultimapBinderProviderWithDependencies. This is done to avoid confusion because the BindingSelection contains mutable state. /**
   * The BindingSelection contains some of the core state and logic for the MapBinder.
   *
   * <p>It lazily computes the value for keys for various permutations of Maps that are provided by
   * this module. It also builds up maps from {@code K} to {@code Binding<V>}, which is used by all
   * of the internal factories to actually provide the desired maps.
   *
   * <p>During initialization time there is only one BindingSelection. It is possible that multiple
   * different BindingSelections are constructed. Specifically, in the case of two different modules
   * each adding bindings to the same MapBinder. If that happens, we define the BindingSelection
   * held by the {@link RealMapProvider} to be the authoritative one. The logic for this exists in
   * {@link RealMultimapBinderProviderWithDependencies}. This is done to avoid confusion because the
   * BindingSelection contains mutable state.
   */
  private static final class BindingSelection<K, V> {
    private enum InitializationState {
      UNINITIALIZED,
      INITIALIZED,
      HAS_ERRORS;
    }

    private final TypeLiteral<K> keyType;
    private final TypeLiteral<V> valueType;
    private final Key<Map<K, V>> mapKey;

    // Lazily computed
    private Key<Map<K, javax.inject.Provider<V>>> javaxProviderMapKey;
    private Key<Map<K, Provider<V>>> providerMapKey;
    private Key<Map<K, Set<V>>> multimapKey;
    private Key<Map<K, Set<Provider<V>>>> providerSetMultimapKey;
    private Key<Map<K, Set<javax.inject.Provider<V>>>> javaxProviderSetMultimapKey;
    private Key<Map<K, Collection<Provider<V>>>> providerCollectionMultimapKey;
    private Key<Map<K, Collection<javax.inject.Provider<V>>>> javaxProviderCollectionMultimapKey;
    private Key<Set<Map.Entry<K, javax.inject.Provider<V>>>> entrySetJavaxProviderKey;

    private final RealMultibinder<Map.Entry<K, Provider<V>>> entrySetBinder;

    private InitializationState initializationState;

    
These are built during initialization and used by all factories to actually provide the
relevant maps. These contain all of the necessary information about the map binder.
/**
     * These are built during initialization and used by all factories to actually provide the
     * relevant maps. These contain all of the necessary information about the map binder.
     */
    private ImmutableMap<K, Binding<V>> mapBindings;

    private ImmutableMap<K, Set<Binding<V>>> multimapBindings;
    private ImmutableList<Map.Entry<K, Binding<V>>> entries;

    
Indicates if this Map permits duplicates. It is initialized during initialization by querying
the injector. This is done because multiple different modules can contribute to a MapBinder,
and any one could set permitDuplicates.
/**
     * Indicates if this Map permits duplicates. It is initialized during initialization by querying
     * the injector. This is done because multiple different modules can contribute to a MapBinder,
     * and any one could set permitDuplicates.
     */
    private boolean permitsDuplicates;

    private BindingSelection(
        TypeLiteral<K> keyType,
        TypeLiteral<V> valueType,
        Key<Map<K, V>> mapKey,
        RealMultibinder<Map.Entry<K, Provider<V>>> entrySetBinder) {
      this.keyType = keyType;
      this.valueType = valueType;
      this.mapKey = mapKey;
      this.entrySetBinder = entrySetBinder;
      this.initializationState = InitializationState.UNINITIALIZED;
    }

    
Will initialize internal data structures.
Returns:
true if initialization was successful, false if there were errors/**
     * Will initialize internal data structures.
     *
     * @return {@code true} if initialization was successful, {@code false} if there were errors
     */
    private boolean tryInitialize(InjectorImpl injector, Errors errors) {
      // Every one of our providers will call this method, so only execute the logic once.
      if (initializationState != InitializationState.UNINITIALIZED) {
        return initializationState != InitializationState.HAS_ERRORS;
      }

      // Multiple different modules can all contribute to the same MapBinder, and if any
      // one of them permits duplicates, then the map binder as a whole will permit duplicates.
      // Since permitDuplicates() may not have been called on this instance, we need to go
      // to the injector to see if permitDuplicates was set.
      permitsDuplicates = entrySetBinder.permitsDuplicates(injector);

      // We now build the Map<K, Set<Binding<V>>> from the entrySetBinder.
      // The entrySetBinder contains all of the ProviderMapEntrys, and once
      // we have those, it's easy to iterate through them to organize them by K.
      Map<K, ImmutableSet.Builder<Binding<V>>> bindingMultimapMutable =
          new LinkedHashMap<K, ImmutableSet.Builder<Binding<V>>>();
      Map<K, Binding<V>> bindingMapMutable = new LinkedHashMap<>();
      Multimap<K, Indexer.IndexedBinding> index = HashMultimap.create();
      Indexer indexer = new Indexer(injector);
      Multimap<K, Binding<V>> duplicates = null;

      ImmutableList.Builder<Map.Entry<K, Binding<V>>> entriesBuilder = ImmutableList.builder();

      // We get all of the Bindings that were put into the entrySetBinder
      for (Binding<Map.Entry<K, Provider<V>>> binding :
          injector.findBindingsByType(entrySetBinder.getElementTypeLiteral())) {
        if (entrySetBinder.containsElement(binding)) {

          // Protected by findBindingByType() and the fact that all providers are added by us
          // in addBinding(). It would theoretically be possible for someone to directly
          // add their own binding to the entrySetBinder, but they shouldn't do that.
          @SuppressWarnings({"unchecked", "rawtypes"})
          ProviderInstanceBinding<ProviderMapEntry<K, V>> entryBinding =
              (ProviderInstanceBinding) binding;

          // We added all these bindings initially, so we know they are ProviderMapEntrys
          @SuppressWarnings({"unchecked", "rawtypes"})
          ProviderMapEntry<K, V> entry = (ProviderMapEntry) entryBinding.getUserSuppliedProvider();
          K key = entry.getKey();

          Key<V> valueKey = entry.getValueKey();
          Binding<V> valueBinding = injector.getExistingBinding(valueKey);

          // Use the indexer to de-dupe user bindings. This is needed because of the
          // uniqueId in RealElement. The uniqueId intentionally circumvents the regular
          // Guice deduplication, so we need to re-implement our own here, ignoring
          // uniqueId.
          if (index.put(key, valueBinding.acceptTargetVisitor(indexer))) {

            entriesBuilder.add(Maps.immutableEntry(key, valueBinding));

            Binding<V> previous = bindingMapMutable.put(key, valueBinding);
            // Check if this is a duplicate binding
            if (previous != null && !permitsDuplicates) {
              if (duplicates == null) {
                // This is linked for both keys and values to maintain order
                duplicates = LinkedHashMultimap.create();
              }

              // We add both the previous and the current value to the duplicates map.
              // This is because if there are three duplicates, we will only execute this code
              // for the second and third, but we want all three values to display a helpful
              // error message. We rely on the multimap to dedupe repeated values.
              duplicates.put(key, previous);
              duplicates.put(key, valueBinding);
            }

            // Don't do extra work unless we need to
            if (permitsDuplicates) {
              // Add the binding, creating a set builder if it's the first time we've seen it
              bindingMultimapMutable
                  .computeIfAbsent(key, k -> ImmutableSet.builder())
                  .add(valueBinding);
            }
          }
        }
      }

      // It is safe to check if duplicates is non-null because if duplicates are allowed,
      // we don't build up this data structure
      if (duplicates != null) {
        initializationState = InitializationState.HAS_ERRORS;
        reportDuplicateKeysError(duplicates, errors);

        return false;
      }

      // Build all of the ImmutableSet.Builders,
      // transforming from Map<K, ImmutableSet.Builder<Binding<V>>> to
      // ImmutableMap<K, Set<Binding<V>>>
      ImmutableMap.Builder<K, Set<Binding<V>>> bindingsMultimapBuilder = ImmutableMap.builder();
      for (Map.Entry<K, ImmutableSet.Builder<Binding<V>>> entry :
          bindingMultimapMutable.entrySet()) {
        bindingsMultimapBuilder.put(entry.getKey(), entry.getValue().build());
      }
      mapBindings = ImmutableMap.copyOf(bindingMapMutable);
      multimapBindings = bindingsMultimapBuilder.build();

      entries = entriesBuilder.build();

      initializationState = InitializationState.INITIALIZED;

      return true;
    }

    private static <K, V> void reportDuplicateKeysError(
        Multimap<K, Binding<V>> duplicates, Errors errors) {
      StringBuilder sb = new StringBuilder("Map injection failed due to duplicated key ");
      boolean first = true;
      for (Map.Entry<K, Collection<Binding<V>>> entry : duplicates.asMap().entrySet()) {
        K dupKey = entry.getKey();

        if (first) {
          first = false;
          sb.append("\"").append(dupKey).append("\", from bindings:\n");
        } else {
          sb.append("\n and key: \"").append(dupKey).append("\", from bindings:\n");
        }

        for (Binding<V> dup : entry.getValue()) {
          sb.append("\t at ").append(Errors.convert(dup.getSource())).append("\n");
        }
      }

      // TODO(user): Add a different error for every duplicated key
      errors.addMessage(sb.toString());
    }

    private boolean containsElement(Element element) {
      if (entrySetBinder.containsElement(element)) {
        return true;
      }

      Key<?> key;
      if (element instanceof Binding) {
        key = ((Binding<?>) element).getKey();
      } else {
        return false; // cannot match;
      }

      return key.equals(getMapKey())
          || key.equals(getProviderMapKey())
          || key.equals(getJavaxProviderMapKey())
          || key.equals(getMultimapKey())
          || key.equals(getProviderSetMultimapKey())
          || key.equals(getJavaxProviderSetMultimapKey())
          || key.equals(getProviderCollectionMultimapKey())
          || key.equals(getJavaxProviderCollectionMultimapKey())
          || key.equals(entrySetBinder.getSetKey())
          || key.equals(getEntrySetJavaxProviderKey())
          || matchesValueKey(key);
    }

    
Returns true if the key indicates this is a value in the map. /** Returns true if the key indicates this is a value in the map. */
    private boolean matchesValueKey(Key<?> key) {
      return key.getAnnotation() instanceof RealElement
          && ((RealElement) key.getAnnotation()).setName().equals(entrySetBinder.getSetName())
          && ((RealElement) key.getAnnotation()).type() == MAPBINDER
          && ((RealElement) key.getAnnotation()).keyType().equals(keyType.toString())
          && key.getTypeLiteral().equals(valueType);
    }

    private Key<Map<K, Provider<V>>> getProviderMapKey() {
      Key<Map<K, Provider<V>>> local = providerMapKey;
      if (local == null) {
        local = providerMapKey = mapKey.ofType(mapOfProviderOf(keyType, valueType));
      }
      return local;
    }

    private Key<Map<K, javax.inject.Provider<V>>> getJavaxProviderMapKey() {
      Key<Map<K, javax.inject.Provider<V>>> local = javaxProviderMapKey;
      if (local == null) {
        local = javaxProviderMapKey = mapKey.ofType(mapOfJavaxProviderOf(keyType, valueType));
      }
      return local;
    }

    private Key<Map<K, Set<V>>> getMultimapKey() {
      Key<Map<K, Set<V>>> local = multimapKey;
      if (local == null) {
        local = multimapKey = mapKey.ofType(mapOf(keyType, setOf(valueType)));
      }
      return local;
    }

    private Key<Map<K, Set<Provider<V>>>> getProviderSetMultimapKey() {
      Key<Map<K, Set<Provider<V>>>> local = providerSetMultimapKey;
      if (local == null) {
        local = providerSetMultimapKey = mapKey.ofType(mapOfSetOfProviderOf(keyType, valueType));
      }
      return local;
    }

    private Key<Map<K, Set<javax.inject.Provider<V>>>> getJavaxProviderSetMultimapKey() {
      Key<Map<K, Set<javax.inject.Provider<V>>>> local = javaxProviderSetMultimapKey;
      if (local == null) {
        local =
            javaxProviderSetMultimapKey =
                mapKey.ofType(mapOfSetOfJavaxProviderOf(keyType, valueType));
      }
      return local;
    }

    private Key<Map<K, Collection<Provider<V>>>> getProviderCollectionMultimapKey() {
      Key<Map<K, Collection<Provider<V>>>> local = providerCollectionMultimapKey;
      if (local == null) {
        local =
            providerCollectionMultimapKey =
                mapKey.ofType(mapOfCollectionOfProviderOf(keyType, valueType));
      }
      return local;
    }

    private Key<Map<K, Collection<javax.inject.Provider<V>>>>
        getJavaxProviderCollectionMultimapKey() {
      Key<Map<K, Collection<javax.inject.Provider<V>>>> local = javaxProviderCollectionMultimapKey;
      if (local == null) {
        local =
            javaxProviderCollectionMultimapKey =
                mapKey.ofType(mapOfCollectionOfJavaxProviderOf(keyType, valueType));
      }
      return local;
    }

    private Key<Set<Map.Entry<K, javax.inject.Provider<V>>>> getEntrySetJavaxProviderKey() {
      Key<Set<Map.Entry<K, javax.inject.Provider<V>>>> local = entrySetJavaxProviderKey;
      if (local == null) {
        local =
            entrySetJavaxProviderKey =
                mapKey.ofType(setOfEntryOfJavaxProviderOf(keyType, valueType));
      }
      return local;
    }

    private ImmutableMap<K, Binding<V>> getMapBindings() {
      checkConfiguration(isInitialized(), "MapBinder has not yet been initialized");
      return mapBindings;
    }

    private ImmutableMap<K, Set<Binding<V>>> getMultimapBindings() {
      checkConfiguration(isInitialized(), "MapBinder has not yet been initialized");
      return multimapBindings;
    }

    private ImmutableList<Map.Entry<K, Binding<V>>> getEntries() {
      checkConfiguration(isInitialized(), "MapBinder has not yet been initialized");
      return entries;
    }

    private boolean isInitialized() {
      return initializationState == InitializationState.INITIALIZED;
    }

    private TypeLiteral<K> getKeyType() {
      return keyType;
    }

    private TypeLiteral<V> getValueType() {
      return valueType;
    }

    private Key<Map<K, V>> getMapKey() {
      return mapKey;
    }

    private RealMultibinder<Map.Entry<K, Provider<V>>> getEntrySetBinder() {
      return entrySetBinder;
    }

    private boolean permitsDuplicates() {
      if (isInitialized()) {
        return permitsDuplicates;
      } else {
        throw new UnsupportedOperationException(
            "permitsDuplicates() not supported for module bindings");
      }
    }

    @Override
    public boolean equals(Object o) {
      return o instanceof BindingSelection && ((BindingSelection<?, ?>) o).mapKey.equals(mapKey);
    }

    @Override
    public int hashCode() {
      return mapKey.hashCode();
    }
  }

  private static final class RealProviderMapProvider<K, V>
      extends RealMapBinderProviderWithDependencies<K, V, Map<K, Provider<V>>> {
    private Map<K, Provider<V>> mapOfProviders;
    private Set<Dependency<?>> dependencies = RealMapBinder.MODULE_DEPENDENCIES;

    private RealProviderMapProvider(BindingSelection<K, V> bindingSelection) {
      super(bindingSelection);
    }

    @Override
    public Set<Dependency<?>> getDependencies() {
      return dependencies;
    }

    @Override
    protected void doInitialize(InjectorImpl injector, Errors errors) {
      ImmutableMap.Builder<K, Provider<V>> mapOfProvidersBuilder = ImmutableMap.builder();
      ImmutableSet.Builder<Dependency<?>> dependenciesBuilder = ImmutableSet.builder();
      for (Map.Entry<K, Binding<V>> entry : bindingSelection.getMapBindings().entrySet()) {
        mapOfProvidersBuilder.put(entry.getKey(), entry.getValue().getProvider());
        dependenciesBuilder.add(Dependency.get(getKeyOfProvider(entry.getValue().getKey())));
      }

      mapOfProviders = mapOfProvidersBuilder.build();
      dependencies = dependenciesBuilder.build();
    }

    @Override
    protected Map<K, Provider<V>> doProvision(InternalContext context, Dependency<?> dependency) {
      return mapOfProviders;
    }
  }

  private static final class RealMapProvider<K, V>
      extends RealMapBinderProviderWithDependencies<K, V, Map<K, V>>
      implements ProviderWithExtensionVisitor<Map<K, V>>, MapBinderBinding<Map<K, V>> {
    private Set<Dependency<?>> dependencies = RealMapBinder.MODULE_DEPENDENCIES;

    
An array of all the injectors.
This is parallel to array of keys below
/**
     * An array of all the injectors.
     *
     * <p>This is parallel to array of keys below
     */
    private SingleParameterInjector<V>[] injectors;

    private K[] keys;

    private RealMapProvider(BindingSelection<K, V> bindingSelection) {
      super(bindingSelection);
    }

    private BindingSelection<K, V> getBindingSelection() {
      return bindingSelection;
    }

    @Override
    protected void doInitialize(InjectorImpl injector, Errors errors) throws ErrorsException {
      @SuppressWarnings("unchecked")
      K[] keysArray = (K[]) new Object[bindingSelection.getMapBindings().size()];
      keys = keysArray;
      ImmutableSet.Builder<Dependency<?>> dependenciesBuilder = ImmutableSet.builder();
      int i = 0;
      for (Map.Entry<K, Binding<V>> entry : bindingSelection.getMapBindings().entrySet()) {
        dependenciesBuilder.add(Dependency.get(entry.getValue().getKey()));
        keys[i] = entry.getKey();
        i++;
      }

      ImmutableSet<Dependency<?>> localDependencies = dependenciesBuilder.build();
      dependencies = localDependencies;

      List<Dependency<?>> dependenciesList = localDependencies.asList();

      // We know the type because we built up our own sets of dependencies, it's just
      // that the interface uses a "?" generic
      @SuppressWarnings("unchecked")
      SingleParameterInjector<V>[] typedInjectors =
          (SingleParameterInjector<V>[]) injector.getParametersInjectors(dependenciesList, errors);
      injectors = typedInjectors;
    }

    @Override
    protected Map<K, V> doProvision(InternalContext context, Dependency<?> dependency)
        throws InternalProvisionException {
      SingleParameterInjector<V>[] localInjectors = injectors;
      if (localInjectors == null) {
        // if injectors == null, then we have no bindings so return the empty map.
        return ImmutableMap.of();
      }

      ImmutableMap.Builder<K, V> resultBuilder = ImmutableMap.builder();
      K[] localKeys = keys;
      for (int i = 0; i < localInjectors.length; i++) {
        SingleParameterInjector<V> injector = localInjectors[i];
        K key = localKeys[i];

        V value = injector.inject(context);

        if (value == null) {
          throw createNullValueException(key, bindingSelection.getMapBindings().get(key));
        }

        resultBuilder.put(key, value);
      }

      return resultBuilder.build();
    }

    @Override
    public Set<Dependency<?>> getDependencies() {
      return dependencies;
    }

    @Override
    @SuppressWarnings("unchecked")
    public <B, W> W acceptExtensionVisitor(
        BindingTargetVisitor<B, W> visitor, ProviderInstanceBinding<? extends B> binding) {
      if (visitor instanceof MultibindingsTargetVisitor) {
        return ((MultibindingsTargetVisitor<Map<K, V>, W>) visitor).visit(this);
      } else {
        return visitor.visit(binding);
      }
    }

    @Override
    public Key<Map<K, V>> getMapKey() {
      return bindingSelection.getMapKey();
    }

    @Override
    public Set<Key<?>> getAlternateMapKeys() {
      return ImmutableSet.of(
          (Key<?>) bindingSelection.getJavaxProviderMapKey(),
          (Key<?>) bindingSelection.getProviderMapKey(),
          (Key<?>) bindingSelection.getProviderSetMultimapKey(),
          (Key<?>) bindingSelection.getJavaxProviderSetMultimapKey(),
          (Key<?>) bindingSelection.getProviderCollectionMultimapKey(),
          (Key<?>) bindingSelection.getJavaxProviderCollectionMultimapKey(),
          (Key<?>) bindingSelection.getMultimapKey());
    }

    @Override
    public TypeLiteral<K> getKeyTypeLiteral() {
      return bindingSelection.getKeyType();
    }

    @Override
    public TypeLiteral<V> getValueTypeLiteral() {
      return bindingSelection.getValueType();
    }

    @Override
    @SuppressWarnings("unchecked")
    public List<Map.Entry<?, Binding<?>>> getEntries() {
      if (bindingSelection.isInitialized()) {
        return (List<Map.Entry<?, Binding<?>>>) (List<?>) bindingSelection.getEntries();
      } else {
        throw new UnsupportedOperationException("getEntries() not supported for module bindings");
      }
    }

    @Override
    public List<Map.Entry<?, Binding<?>>> getEntries(Iterable<? extends Element> elements) {
      // Iterate over the elements, building up the below maps
      // This is a preprocessing step allowing us to only iterate over elements
      // once and have O(n) runtime
      ImmutableMultimap.Builder<K, Key<V>> keyToValueKeyBuilder = ImmutableMultimap.builder();
      ImmutableMap.Builder<Key<V>, Binding<V>> valueKeyToBindingBuilder = ImmutableMap.builder();
      ImmutableMap.Builder<Key<V>, K> valueKeyToKeyBuilder = ImmutableMap.builder();
      ImmutableMap.Builder<Key<V>, Binding<Map.Entry<K, Provider<V>>>>
          valueKeyToEntryBindingBuilder = ImmutableMap.builder();
      for (Element element : elements) {
        if (element instanceof Binding) {
          Binding<?> binding = (Binding<?>) element;
          if (bindingSelection.matchesValueKey(binding.getKey())
              && binding.getKey().getTypeLiteral().equals(bindingSelection.valueType)) {
            // Safe because of the check on the type literal above
            @SuppressWarnings("unchecked")
            Binding<V> typedBinding = (Binding<V>) binding;
            Key<V> typedKey = typedBinding.getKey();
            valueKeyToBindingBuilder.put(typedKey, typedBinding);
          }
        }

        if (element instanceof ProviderInstanceBinding
            && bindingSelection.getEntrySetBinder().containsElement(element)) {
          // Safe because of the instanceof check, and containsElement() check
          @SuppressWarnings({"unchecked", "rawtypes"})
          ProviderInstanceBinding<Map.Entry<K, Provider<V>>> entryBinding =
              (ProviderInstanceBinding) element;

          // Safe because of the check for containsElement() above
          @SuppressWarnings("unchecked")
          Provider<Map.Entry<K, Provider<V>>> typedProvider =
              (Provider<Map.Entry<K, Provider<V>>>) entryBinding.getUserSuppliedProvider();
          Provider<Map.Entry<K, Provider<V>>> userSuppliedProvider = typedProvider;

          if (userSuppliedProvider instanceof ProviderMapEntry) {
            // Safe because of the instanceof check
            @SuppressWarnings("unchecked")
            ProviderMapEntry<K, V> typedUserSuppliedProvider =
                (ProviderMapEntry<K, V>) userSuppliedProvider;
            ProviderMapEntry<K, V> entry = typedUserSuppliedProvider;

            keyToValueKeyBuilder.put(entry.getKey(), entry.getValueKey());
            valueKeyToEntryBindingBuilder.put(entry.getValueKey(), entryBinding);
            valueKeyToKeyBuilder.put(entry.getValueKey(), entry.getKey());
          }
        }
      }

      ImmutableMultimap<K, Key<V>> keyToValueKey = keyToValueKeyBuilder.build();
      ImmutableMap<Key<V>, K> valueKeyToKey = valueKeyToKeyBuilder.build();
      ImmutableMap<Key<V>, Binding<V>> valueKeyToBinding = valueKeyToBindingBuilder.build();
      ImmutableMap<Key<V>, Binding<Map.Entry<K, Provider<V>>>> valueKeyToEntryBinding =
          valueKeyToEntryBindingBuilder.build();

      // Check that there is a 1:1 mapping from keys from the ProviderMapEntrys to the
      // keys from the Bindings.
      Set<Key<V>> keysFromProviderMapEntrys = Sets.newHashSet(keyToValueKey.values());
      Set<Key<V>> keysFromBindings = valueKeyToBinding.keySet();

      if (!keysFromProviderMapEntrys.equals(keysFromBindings)) {
        Set<Key<V>> keysOnlyFromProviderMapEntrys =
            Sets.difference(keysFromProviderMapEntrys, keysFromBindings);
        Set<Key<V>> keysOnlyFromBindings =
            Sets.difference(keysFromBindings, keysFromProviderMapEntrys);

        StringBuilder sb = new StringBuilder("Expected a 1:1 mapping from map keys to values.");

        if (!keysOnlyFromBindings.isEmpty()) {
          sb.append(
              Errors.format("%nFound these Bindings that were missing an associated entry:%n"));
          for (Key<V> key : keysOnlyFromBindings) {
            sb.append(
                Errors.format("  %s bound at: %s%n", key, valueKeyToBinding.get(key).getSource()));
          }
        }

        if (!keysOnlyFromProviderMapEntrys.isEmpty()) {
          sb.append(Errors.format("%nFound these map keys without a corresponding value:%n"));
          for (Key<V> key : keysOnlyFromProviderMapEntrys) {
            sb.append(
                Errors.format(
                    "  '%s' bound at: %s%n",
                    valueKeyToKey.get(key), valueKeyToEntryBinding.get(key).getSource()));
          }
        }

        throw new IllegalArgumentException(sb.toString());
      }

      // Now that we have the two maps, generate the result map
      ImmutableList.Builder<Map.Entry<?, Binding<?>>> resultBuilder = ImmutableList.builder();
      for (Map.Entry<K, Key<V>> entry : keyToValueKey.entries()) {
        Binding<?> binding = valueKeyToBinding.get(entry.getValue());
        // No null check for binding needed because of the above check to make sure all the
        // values in keyToValueKey are present as keys in valueKeyToBinding

        @SuppressWarnings({"unchecked", "rawtypes"})
        Map.Entry<?, Binding<?>> newEntry =
            (Map.Entry) Maps.immutableEntry(entry.getKey(), binding);
        resultBuilder.add(newEntry);
      }
      return resultBuilder.build();
    }

    @Override
    public boolean permitsDuplicates() {
      if (bindingSelection.isInitialized()) {
        return bindingSelection.permitsDuplicates();
      } else {
        throw new UnsupportedOperationException(
            "permitsDuplicates() not supported for module bindings");
      }
    }

    @Override
    public boolean containsElement(Element element) {
      return bindingSelection.containsElement(element);
    }
  }

  
Binds Map<K, Set<V>> and {Map<K, Set<Provider<V>>>. 
This will only exist if permitDuplicates() is called.
/**
   * Binds {@code Map<K, Set<V>>} and {{@code Map<K, Set<Provider<V>>>}.
   *
   * <p>This will only exist if permitDuplicates() is called.
   */
  private static final class MultimapBinder<K, V> implements Module {
    private final BindingSelection<K, V> bindingSelection;

    private MultimapBinder(BindingSelection<K, V> bindingSelection) {
      this.bindingSelection = bindingSelection;
    }

    @Override
    public void configure(Binder binder) {
      // Binds a Map<K, Set<Provider<V>>>
      Provider<Map<K, Set<Provider<V>>>> multimapProvider =
          new RealProviderMultimapProvider<K, V>(bindingSelection.getMapKey());
      binder.bind(bindingSelection.getProviderSetMultimapKey()).toProvider(multimapProvider);

      // Provide links from a few different public keys to the providerMultimapKey.
      // The collection this exposes is internally an ImmutableMap, so it's OK to massage
      // the guice Provider to javax Provider in the value (since the guice Provider implements
      // javax Provider).
      @SuppressWarnings({"unchecked", "rawtypes"})
      Provider<Map<K, Set<javax.inject.Provider<V>>>> javaxProvider = (Provider) multimapProvider;
      binder.bind(bindingSelection.getJavaxProviderSetMultimapKey()).toProvider(javaxProvider);

      @SuppressWarnings({"unchecked", "rawtypes"})
      Provider<Map<K, Collection<Provider<V>>>> collectionProvider = (Provider) multimapProvider;
      binder
          .bind(bindingSelection.getProviderCollectionMultimapKey())
          .toProvider(collectionProvider);

      @SuppressWarnings({"unchecked", "rawtypes"})
      Provider<Map<K, Collection<javax.inject.Provider<V>>>> collectionJavaxProvider =
          (Provider) multimapProvider;
      binder
          .bind(bindingSelection.getJavaxProviderCollectionMultimapKey())
          .toProvider(collectionJavaxProvider);

      // Binds a Map<K, Set<V>>
      @SuppressWarnings({"unchecked", "rawtypes"})
      Provider<Map<K, Set<V>>> realMultimapProvider =
          new RealMultimapProvider(bindingSelection.getMapKey());
      binder.bind(bindingSelection.getMultimapKey()).toProvider(realMultimapProvider);
    }

    @Override
    public int hashCode() {
      return bindingSelection.hashCode();
    }

    @Override
    public boolean equals(Object o) {
      return o instanceof MultimapBinder
          && ((MultimapBinder<?, ?>) o).bindingSelection.equals(bindingSelection);
    }

    private static final class RealProviderMultimapProvider<K, V>
        extends RealMultimapBinderProviderWithDependencies<K, V, Map<K, Set<Provider<V>>>> {
      private Map<K, Set<Provider<V>>> multimapOfProviders;
      private Set<Dependency<?>> dependencies = RealMapBinder.MODULE_DEPENDENCIES;

      private RealProviderMultimapProvider(Key<Map<K, V>> mapKey) {
        super(mapKey);
      }

      @Override
      public Set<Dependency<?>> getDependencies() {
        return dependencies;
      }

      @Override
      protected void doInitialize(InjectorImpl injector, Errors errors) {
        ImmutableMap.Builder<K, Set<Provider<V>>> multimapOfProvidersBuilder =
            ImmutableMap.builder();
        ImmutableSet.Builder<Dependency<?>> dependenciesBuilder = ImmutableSet.builder();
        for (Map.Entry<K, Set<Binding<V>>> entry :
            bindingSelection.getMultimapBindings().entrySet()) {
          ImmutableSet.Builder<Provider<V>> providersBuilder = ImmutableSet.builder();
          for (Binding<V> binding : entry.getValue()) {
            providersBuilder.add(binding.getProvider());
            dependenciesBuilder.add(Dependency.get(getKeyOfProvider(binding.getKey())));
          }

          multimapOfProvidersBuilder.put(entry.getKey(), providersBuilder.build());
        }
        multimapOfProviders = multimapOfProvidersBuilder.build();
        dependencies = dependenciesBuilder.build();
      }

      @Override
      protected Map<K, Set<Provider<V>>> doProvision(
          InternalContext context, Dependency<?> dependency) {
        return multimapOfProviders;
      }
    }

    private static final class RealMultimapProvider<K, V>
        extends RealMultimapBinderProviderWithDependencies<K, V, Map<K, Set<V>>> {

      
A simple class to hold a key and the associated bindings as an array.
Arrays are used for performance.
/**
       * A simple class to hold a key and the associated bindings as an array.
       *
       * <p>Arrays are used for performance.
       */
      private static final class PerKeyData<K, V> {
        private final K key;
        private final Binding<V>[] bindings;
        private final SingleParameterInjector<V>[] injectors;

        private PerKeyData(K key, Binding<V>[] bindings, SingleParameterInjector<V>[] injectors) {
          Preconditions.checkArgument(bindings.length == injectors.length);

          this.key = key;
          this.bindings = bindings;
          this.injectors = injectors;
        }
      }

      private Set<Dependency<?>> dependencies = RealMapBinder.MODULE_DEPENDENCIES;

      private PerKeyData<K, V>[] perKeyDatas;

      private RealMultimapProvider(Key<Map<K, V>> mapKey) {
        super(mapKey);
      }

      @Override
      public Set<Dependency<?>> getDependencies() {
        return dependencies;
      }

      @Override
      protected void doInitialize(InjectorImpl injector, Errors errors) throws ErrorsException {
        @SuppressWarnings({"unchecked", "rawtypes"})
        PerKeyData<K, V>[] typedPerKeyData =
            new PerKeyData[bindingSelection.getMapBindings().size()];
        perKeyDatas = typedPerKeyData;
        ImmutableSet.Builder<Dependency<?>> dependenciesBuilder = ImmutableSet.builder();
        List<Dependency<?>> dependenciesForKey = Lists.newArrayList();
        int i = 0;
        for (Map.Entry<K, Set<Binding<V>>> entry :
            bindingSelection.getMultimapBindings().entrySet()) {
          // Clear the list of dependencies because we're reusing it for each different key
          dependenciesForKey.clear();

          Set<Binding<V>> bindings = entry.getValue();
          @SuppressWarnings({"unchecked", "rawtypes"})
          Binding<V>[] typedBindings = new Binding[bindings.size()];
          Binding<V>[] bindingsArray = typedBindings;
          int j = 0;
          for (Binding<V> binding : bindings) {
            Dependency<V> dependency = Dependency.get(binding.getKey());
            dependenciesBuilder.add(dependency);
            dependenciesForKey.add(dependency);
            bindingsArray[j] = binding;
            j++;
          }

          @SuppressWarnings("unchecked")
          SingleParameterInjector<V>[] injectors =
              (SingleParameterInjector<V>[])
                  injector.getParametersInjectors(dependenciesForKey, errors);

          perKeyDatas[i] = new PerKeyData<>(entry.getKey(), bindingsArray, injectors);
          i++;
        }

        dependencies = dependenciesBuilder.build();
      }

      @Override
      protected Map<K, Set<V>> doProvision(InternalContext context, Dependency<?> dependency)
          throws InternalProvisionException {
        ImmutableMap.Builder<K, Set<V>> resultBuilder = ImmutableMap.builder();

        for (PerKeyData<K, V> perKeyData : perKeyDatas) {
          ImmutableSet.Builder<V> bindingsBuilder = ImmutableSet.builder();
          SingleParameterInjector<V>[] injectors = perKeyData.injectors;
          for (int i = 0; i < injectors.length; i++) {
            SingleParameterInjector<V> injector = injectors[i];
            V value = injector.inject(context);

            if (value == null) {
              throw createNullValueException(perKeyData.key, perKeyData.bindings[i]);
            }

            bindingsBuilder.add(value);
          }

          resultBuilder.put(perKeyData.key, bindingsBuilder.build());
        }

        return resultBuilder.build();
      }
    }
  }

  
A factory for a Map.Entry<K, Provider<V>>. /** A factory for a {@code Map.Entry<K, Provider<V>>}. */
  // VisibleForTesting
  static final class ProviderMapEntry<K, V>
      extends InternalProviderInstanceBindingImpl.Factory<Map.Entry<K, Provider<V>>> {
    private final K key;
    private final Key<V> valueKey;
    private Map.Entry<K, Provider<V>> entry;

    ProviderMapEntry(K key, Key<V> valueKey) {
      super(InitializationTiming.EAGER);
      this.key = key;
      this.valueKey = valueKey;
    }

    @Override
    public Set<Dependency<?>> getDependencies() {
      // The dependencies are Key<Provider<V>>
      return ImmutableSet.<Dependency<?>>of(Dependency.get(getKeyOfProvider(valueKey)));
    }

    @Override
    void initialize(InjectorImpl injector, Errors errors) {
      Binding<V> valueBinding = injector.getExistingBinding(valueKey);
      entry = Maps.immutableEntry(key, valueBinding.getProvider());
    }

    @Override
    protected Map.Entry<K, Provider<V>> doProvision(
        InternalContext context, Dependency<?> dependency) {
      return entry;
    }

    K getKey() {
      return key;
    }

    Key<V> getValueKey() {
      return valueKey;
    }

    @Override
    public boolean equals(Object obj) {
      if (obj instanceof ProviderMapEntry) {
        ProviderMapEntry<?, ?> o = (ProviderMapEntry<?, ?>) obj;
        return key.equals(o.key) && valueKey.equals(o.valueKey);
      }
      return false;
    }

    @Override
    public int hashCode() {
      return Objects.hashCode(key, valueKey);
    }

    @Override
    public String toString() {
      return "ProviderMapEntry(" + key + ", " + valueKey + ")";
    }
  }

  
A base class for ProviderWithDependencies that need equality based on a specific object. /** A base class for ProviderWithDependencies that need equality based on a specific object. */
  private abstract static class RealMapBinderProviderWithDependencies<K, V, P>
      extends InternalProviderInstanceBindingImpl.Factory<P> {
    final BindingSelection<K, V> bindingSelection;

    private RealMapBinderProviderWithDependencies(BindingSelection<K, V> bindingSelection) {
      // While MapBinders only depend on bindings created in modules so we could theoretically
      // initialize eagerly, they also depend on
      // 1. findBindingsByType returning results
      // 2. being able to call BindingImpl.acceptTargetVisitor
      // neither of those is available during eager initialization, so we use DELAYED
      super(InitializationTiming.DELAYED);

      this.bindingSelection = bindingSelection;
    }

    @Override
    final void initialize(InjectorImpl injector, Errors errors) throws ErrorsException {
      if (bindingSelection.tryInitialize(injector, errors)) {
        doInitialize(injector, errors);
      }
    }

    
Initialize the factory. BindingSelection is guaranteed to be initialized at this point and
this will be called prior to any provisioning.
/**
     * Initialize the factory. BindingSelection is guaranteed to be initialized at this point and
     * this will be called prior to any provisioning.
     */
    protected abstract void doInitialize(InjectorImpl injector, Errors errors)
        throws ErrorsException;

    @Override
    public boolean equals(Object obj) {
      return obj != null
          && this.getClass() == obj.getClass()
          && bindingSelection.equals(
              ((RealMapBinderProviderWithDependencies<?, ?, ?>) obj).bindingSelection);
    }

    @Override
    public int hashCode() {
      return bindingSelection.hashCode();
    }
  }

  
A base class for ProviderWithDependencies that need equality based on a specific object.
This differs from RealMapBinderProviderWithDependencies in that it gets the 
bindingSelection from the injector at initialization time, rather than in the constructor. This is done to allow all the providers to operate on the same instance of the BindingSelection. /**
   * A base class for ProviderWithDependencies that need equality based on a specific object.
   *
   * <p>This differs from {@link RealMapBinderProviderWithDependencies} in that it gets the {@code
   * bindingSelection} from the injector at initialization time, rather than in the constructor.
   * This is done to allow all the providers to operate on the same instance of the {@link
   * BindingSelection}.
   */
  private abstract static class RealMultimapBinderProviderWithDependencies<K, V, P>
      extends InternalProviderInstanceBindingImpl.Factory<P> {
    final Key<Map<K, V>> mapKey;
    BindingSelection<K, V> bindingSelection;

    private RealMultimapBinderProviderWithDependencies(Key<Map<K, V>> mapKey) {
      // While MapBinders only depend on bindings created in modules so we could theoretically
      // initialize eagerly, they also depend on
      // 1. findBindingsByType returning results
      // 2. being able to call BindingImpl.acceptTargetVisitor
      // neither of those is available during eager initialization, so we use DELAYED
      super(InitializationTiming.DELAYED);

      this.mapKey = mapKey;
    }

    
This will get the authoritative BindingSelection from the map provider. This guarantees that everyone has the same instance of the bindingSelection and sees consistent state. /**
     * This will get the authoritative {@link BindingSelection} from the map provider. This
     * guarantees that everyone has the same instance of the bindingSelection and sees consistent
     * state.
     */
    @Override
    final void initialize(InjectorImpl injector, Errors errors) throws ErrorsException {
      Binding<Map<K, V>> mapBinding = injector.getExistingBinding(mapKey);
      ProviderInstanceBinding<Map<K, V>> providerInstanceBinding =
          (ProviderInstanceBinding<Map<K, V>>) mapBinding;
      @SuppressWarnings("unchecked")
      RealMapProvider<K, V> mapProvider =
          (RealMapProvider<K, V>) providerInstanceBinding.getUserSuppliedProvider();

      this.bindingSelection = mapProvider.getBindingSelection();

      if (bindingSelection.tryInitialize(injector, errors)) {
        doInitialize(injector, errors);
      }
    }

    
Initialize the factory. BindingSelection is guaranteed to be initialized at this point and
this will be called prior to any provisioning.
/**
     * Initialize the factory. BindingSelection is guaranteed to be initialized at this point and
     * this will be called prior to any provisioning.
     */
    abstract void doInitialize(InjectorImpl injector, Errors errors) throws ErrorsException;

    @Override
    public boolean equals(Object obj) {
      return obj != null
          && this.getClass() == obj.getClass()
          && mapKey.equals(((RealMultimapBinderProviderWithDependencies<?, ?, ?>) obj).mapKey);
    }

    @Override
    public int hashCode() {
      return mapKey.hashCode();
    }
  }

  private static <K, V> InternalProvisionException createNullValueException(
      K key, Binding<V> binding) {
    return InternalProvisionException.create(
        "Map injection failed due to null value for key \"%s\", bound at: %s",
        key, binding.getSource());
  }
}