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/*
 * Copyright (C) 2007 The Guava 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 com.google.common.collect;

import static com.google.common.base.Preconditions.checkNotNull;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.primitives.Primitives;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.io.Serializable;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;

/**
 * A mutable class-to-instance map backed by an arbitrary user-provided map. See also {@link
 * ImmutableClassToInstanceMap}.
 *
 * See the Guava User Guide article on  {@code
 * ClassToInstanceMap}.
 *
 * @author Kevin Bourrillion
 * @since 2.0
 */
@GwtIncompatible
@SuppressWarnings("serial") // using writeReplace instead of standard serialization
public final class MutableClassToInstanceMap extends ForwardingMap, B>
    implements ClassToInstanceMap, Serializable {

  /**
   * Returns a new {@code MutableClassToInstanceMap} instance backed by a {@link
   * HashMap} using the default initial capacity and load factor.
   */
  public static  MutableClassToInstanceMap create() {
    return new MutableClassToInstanceMap(new HashMap, B>());
  }

  /**
   * Returns a new {@code MutableClassToInstanceMap} instance backed by a given
   * empty {@code backingMap}. The caller surrenders control of the backing map,
   * and thus should not allow any direct references to it to remain accessible.
   */
  public static  MutableClassToInstanceMap create(Map, B> backingMap) {
    return new MutableClassToInstanceMap(backingMap);
  }

  private final Map, B> delegate;

  private MutableClassToInstanceMap(Map, B> delegate) {
    this.delegate = checkNotNull(delegate);
  }

  @Override
  protected Map, B> delegate() {
    return delegate;
  }

  static  Entry, B> checkedEntry(final Entry, B> entry) {
    return new ForwardingMapEntry, B>() {
      @Override
      protected Entry, B> delegate() {
        return entry;
      }

      @Override
      public B setValue(B value) {
        return super.setValue(cast(getKey(), value));
      }
    };
  }

  @Override
  public Set, B>> entrySet() {
    return new ForwardingSet, B>>() {

      @Override
      protected Set, B>> delegate() {
        return MutableClassToInstanceMap.this.delegate().entrySet();
      }

      @Override
      public Iterator, B>> iterator() {
        return new TransformedIterator, B>, Entry, B>>(
            delegate().iterator()) {
          @Override
          Entry, B> transform(Entry, B> from) {
            return checkedEntry(from);
          }
        };
      }

      @Override
      public Object[] toArray() {
        return standardToArray();
      }

      @Override
      public  T[] toArray(T[] array) {
        return standardToArray(array);
      }
    };
  }

  @Override
  @CanIgnoreReturnValue
  public B put(Class key, B value) {
    return super.put(key, cast(key, value));
  }

  @Override
  public void putAll(Map, ? extends B> map) {
    Map, B> copy = new LinkedHashMap<>(map);
    for (Entry, B> entry : copy.entrySet()) {
      cast(entry.getKey(), entry.getValue());
    }
    super.putAll(copy);
  }

  @CanIgnoreReturnValue
  @Override
  public  T putInstance(Class type, T value) {
    return cast(type, put(type, value));
  }

  @Override
  public  T getInstance(Class type) {
    return cast(type, get(type));
  }

  @CanIgnoreReturnValue
  private static  T cast(Class type, B value) {
    return Primitives.wrap(type).cast(value);
  }

  private Object writeReplace() {
    return new SerializedForm(delegate());
  }

  /**
   * Serialized form of the map, to avoid serializing the constraint.
   */
  private static final class SerializedForm implements Serializable {
    private final Map, B> backingMap;

    SerializedForm(Map, B> backingMap) {
      this.backingMap = backingMap;
    }

    Object readResolve() {
      return create(backingMap);
    }

    private static final long serialVersionUID = 0;
  }
}