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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.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;
+ }
+
+ 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;
+}