/*
 * Copyright (C) 2008 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 java.io.Serializable;
import java.util.Map.Entry;

import javax.annotation.Nullable;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;

/**
 * {@code values()} implementation for {@link ImmutableMap}.
 *
 * @author Jesse Wilson
 * @author Kevin Bourrillion
 */
@GwtCompatible(emulated = true)
final class ImmutableMapValues<K, V> extends ImmutableCollection<V> {
	private final ImmutableMap<K, V> map;

	ImmutableMapValues(ImmutableMap<K, V> map) {
		this.map = map;
	}

	@Override
	public int size() {
		return map.size();
	}

	@Override
	public UnmodifiableIterator<V> iterator() {
		return Maps.valueIterator(map.entrySet().iterator());
	}

	@Override
	public boolean contains(@Nullable Object object) {
		return object != null && Iterators.contains(iterator(), object);
	}

	@Override
	boolean isPartialView() {
		return true;
	}

	@Override
	ImmutableList<V> createAsList() {
		final ImmutableList<Entry<K, V>> entryList = map.entrySet().asList();
		return new ImmutableAsList<V>() {
			@Override
			public V get(int index) {
				return entryList.get(index).getValue();
			}

			@Override
			ImmutableCollection<V> delegateCollection() {
				return ImmutableMapValues.this;
			}
		};
	}

	@GwtIncompatible("serialization")
	@Override
	Object writeReplace() {
		return new SerializedForm<V>(map);
	}

	@GwtIncompatible("serialization")
	private static class SerializedForm<V> implements Serializable {
		final ImmutableMap<?, V> map;

		SerializedForm(ImmutableMap<?, V> map) {
			this.map = map;
		}

		Object readResolve() {
			return map.values();
		}

		private static final long serialVersionUID = 0;
	}
}