/*
* 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.
HashMap;
/**
* Multiset implementation backed by a {@link HashMap}.
*
* @author Kevin Bourrillion
* @author Jared Levy
* @since 2.0 (imported from Google Collections Library)
*/
@
GwtCompatible(serializable = true, emulated = true)
public final class
HashMultiset<E> extends
AbstractMapBasedMultiset<E> {
/**
* Creates a new, empty {@code HashMultiset} using the default initial
* capacity.
*/
public static <E>
HashMultiset<E>
create() {
return new
HashMultiset<E>();
}
/**
* Creates a new, empty {@code HashMultiset} 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>
HashMultiset<E>
create(int
distinctElements) {
return new
HashMultiset<E>(
distinctElements);
}
/**
* Creates a new {@code HashMultiset} 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>
HashMultiset<E>
create(
Iterable<? extends E>
elements) {
HashMultiset<E>
multiset =
create(
Multisets.
inferDistinctElements(
elements));
Iterables.
addAll(
multiset,
elements);
return
multiset;
}
private
HashMultiset() {
super(new
HashMap<E,
Count>());
}
private
HashMultiset(int
distinctElements) {
super(
Maps.<E,
Count>
newHashMapWithExpectedSize(
distinctElements));
}
/**
* @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(
Maps.<E,
Count>
newHashMapWithExpectedSize(
distinctElements));
Serialization.
populateMultiset(this,
stream,
distinctElements);
}
@
GwtIncompatible("Not needed in emulated source.")
private static final long
serialVersionUID = 0;
}