/*
 * 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 com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.LinkedHashMap;

A Multiset implementation with predictable iteration order. Its iterator orders elements according to when the first occurrence of the element was added. When the multiset contains multiple instances of an element, those instances are consecutive in the iteration order. If all occurrences of an element are removed, after which that element is added to the multiset, the element will appear at the end of the iteration. 
See the Guava User Guide article on  
Multiset.
Author:
Kevin Bourrillion, Jared Levy
Since:
2.0/**
 * A {@code Multiset} implementation with predictable iteration order. Its iterator orders elements
 * according to when the first occurrence of the element was added. When the multiset contains
 * multiple instances of an element, those instances are consecutive in the iteration order. If all
 * occurrences of an element are removed, after which that element is added to the multiset, the
 * element will appear at the end of the iteration.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/NewCollectionTypesExplained#multiset"> {@code
 * Multiset}</a>.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy
 * @since 2.0
 */
@GwtCompatible(serializable = true, emulated = true)
@SuppressWarnings("serial") // we're overriding default serialization
public final class LinkedHashMultiset<E> extends AbstractMapBasedMultiset<E> {

  
Creates a new, empty LinkedHashMultiset using the default initial capacity. /** Creates a new, empty {@code LinkedHashMultiset} using the default initial capacity. */
  public static <E> LinkedHashMultiset<E> create() {
    return new LinkedHashMultiset<E>();
  }

  
Creates a new, empty LinkedHashMultiset with the specified expected number of distinct elements. 
Params:
distinctElements – the expected number of distinct elements
Throws:
IllegalArgumentException – if distinctElements is negative/**
   * Creates a new, empty {@code LinkedHashMultiset} with the specified expected number of distinct
   * elements.
   *
   * @param distinctElements the expected number of distinct elements
   * @throws IllegalArgumentException if {@code distinctElements} is negative
   */
  public static <E> LinkedHashMultiset<E> create(int distinctElements) {
    return new LinkedHashMultiset<E>(distinctElements);
  }

  
Creates a new LinkedHashMultiset containing the specified elements. 
This implementation is highly efficient when elements is itself a Multiset. 
Params:
elements – the elements that the multiset should contain/**
   * Creates a new {@code LinkedHashMultiset} containing the specified elements.
   *
   * <p>This implementation is highly efficient when {@code elements} is itself a {@link Multiset}.
   *
   * @param elements the elements that the multiset should contain
   */
  public static <E> LinkedHashMultiset<E> create(Iterable<? extends E> elements) {
    LinkedHashMultiset<E> multiset = create(Multisets.inferDistinctElements(elements));
    Iterables.addAll(multiset, elements);
    return multiset;
  }

  private LinkedHashMultiset() {
    super(new LinkedHashMap<E, Count>());
  }

  private LinkedHashMultiset(int distinctElements) {
    super(Maps.<E, Count>newLinkedHashMapWithExpectedSize(distinctElements));
  }

  
@serialData
the number of distinct elements, the first element, its count, the second element,
    its count, and so on/**
   * @serialData the number of distinct elements, the first element, its count, the second element,
   *     its count, and so on
   */
  @GwtIncompatible // java.io.ObjectOutputStream
  private void writeObject(ObjectOutputStream stream) throws IOException {
    stream.defaultWriteObject();
    Serialization.writeMultiset(this, stream);
  }

  @GwtIncompatible // java.io.ObjectInputStream
  private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
    stream.defaultReadObject();
    int distinctElements = Serialization.readCount(stream);
    setBackingMap(new LinkedHashMap<E, Count>());
    Serialization.populateMultiset(this, stream, distinctElements);
  }

  @GwtIncompatible // not needed in emulated source
  private static final long serialVersionUID = 0;
}