Update #0 - First Release

sources/main/java/com/google/common/collect/EnumMultiset.java

@@ -0,0 +1,109 @@
+/*
+ * 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 java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.util.EnumMap;
+import java.util.Iterator;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.common.annotations.GwtIncompatible;
+
+/**
+ * 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;
+}