/*
* 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.checkArgument;
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.
EnumMap;
import java.util.
Iterator;
/**
* Multiset implementation backed by an {@link EnumMap}.
*
* <p>See the Guava User Guide article on <a href=
* "http://code.google.com/p/guava-libraries/wiki/NewCollectionTypesExplained#Multiset">
* {@code Multiset}</a>.
*
* @author Jared Levy
* @since 2.0 (imported from Google Collections Library)
*/
@
GwtCompatible(emulated = true)
public final class
EnumMultiset<E extends
Enum<E>> extends
AbstractMapBasedMultiset<E> {
/** Creates an empty {@code EnumMultiset}. */
public static <E extends
Enum<E>>
EnumMultiset<E>
create(
Class<E>
type) {
return new
EnumMultiset<E>(
type);
}
/**
* Creates a new {@code EnumMultiset} 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
* @throws IllegalArgumentException if {@code elements} is empty
*/
public static <E extends
Enum<E>>
EnumMultiset<E>
create(
Iterable<E>
elements) {
Iterator<E>
iterator =
elements.
iterator();
checkArgument(
iterator.
hasNext(), "EnumMultiset constructor passed empty Iterable");
EnumMultiset<E>
multiset = new
EnumMultiset<E>(
iterator.
next().
getDeclaringClass());
Iterables.
addAll(
multiset,
elements);
return
multiset;
}
/**
* Returns a new {@code EnumMultiset} instance containing the given elements. Unlike
* {@link EnumMultiset#create(Iterable)}, this method does not produce an exception on an empty
* iterable.
*
* @since 14.0
*/
public static <E extends
Enum<E>>
EnumMultiset<E>
create(
Iterable<E>
elements,
Class<E>
type) {
EnumMultiset<E>
result =
create(
type);
Iterables.
addAll(
result,
elements);
return
result;
}
private transient
Class<E>
type;
/** Creates an empty {@code EnumMultiset}. */
private
EnumMultiset(
Class<E>
type) {
super(
WellBehavedMap.
wrap(new
EnumMap<E,
Count>(
type)));
this.
type =
type;
}
@
GwtIncompatible("java.io.ObjectOutputStream")
private void
writeObject(
ObjectOutputStream stream) throws
IOException {
stream.
defaultWriteObject();
stream.
writeObject(
type);
Serialization.
writeMultiset(this,
stream);
}
/**
* @serialData the {@code Class<E>} for the enum type, the number of distinct
* elements, the first element, its count, the second element, its
* count, and so on
*/
@
GwtIncompatible("java.io.ObjectInputStream")
private void
readObject(
ObjectInputStream stream) throws
IOException,
ClassNotFoundException {
stream.
defaultReadObject();
@
SuppressWarnings("unchecked") // reading data stored by writeObject
Class<E>
localType = (
Class<E>)
stream.
readObject();
type =
localType;
setBackingMap(
WellBehavedMap.
wrap(new
EnumMap<E,
Count>(
type)));
Serialization.
populateMultiset(this,
stream);
}
@
GwtIncompatible("Not needed in emulated source")
private static final long
serialVersionUID = 0;
}