Update #0 - First Release

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

@@ -0,0 +1,128 @@
+/*
+ * 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.checkNotNull;
+
+import java.io.IOException;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.util.EnumMap;
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.annotation.Nullable;
+
+import com.google.common.annotations.GwtCompatible;
+import com.google.common.annotations.GwtIncompatible;
+
+/**
+ * A {@code BiMap} backed by an {@code EnumMap} instance for keys-to-values, and
+ * a {@code HashMap} instance for values-to-keys. Null keys are not permitted,
+ * but null values are. An {@code EnumHashBiMap} and its inverse are both
+ * serializable.
+ * 
+ * <p>
+ * See the Guava User Guide article on <a href=
+ * "http://code.google.com/p/guava-libraries/wiki/NewCollectionTypesExplained#BiMap">
+ * {@code BiMap}</a>.
+ *
+ * @author Mike Bostock
+ * @since 2.0 (imported from Google Collections Library)
+ */
+@GwtCompatible(emulated = true)
+public final class EnumHashBiMap<K extends Enum<K>, V> extends AbstractBiMap<K, V> {
+	private transient Class<K> keyType;
+
+	/**
+	 * Returns a new, empty {@code EnumHashBiMap} using the specified key type.
+	 *
+	 * @param keyType the key type
+	 */
+	public static <K extends Enum<K>, V> EnumHashBiMap<K, V> create(Class<K> keyType) {
+		return new EnumHashBiMap<K, V>(keyType);
+	}
+
+	/**
+	 * Constructs a new bimap with the same mappings as the specified map. If the
+	 * specified map is an {@code EnumHashBiMap} or an {@link EnumBiMap}, the new
+	 * bimap has the same key type as the input bimap. Otherwise, the specified map
+	 * must contain at least one mapping, in order to determine the key type.
+	 *
+	 * @param map the map whose mappings are to be placed in this map
+	 * @throws IllegalArgumentException if map is not an {@code EnumBiMap} or an
+	 *                                  {@code EnumHashBiMap} instance and contains
+	 *                                  no mappings
+	 */
+	public static <K extends Enum<K>, V> EnumHashBiMap<K, V> create(Map<K, ? extends V> map) {
+		EnumHashBiMap<K, V> bimap = create(EnumBiMap.inferKeyType(map));
+		bimap.putAll(map);
+		return bimap;
+	}
+
+	private EnumHashBiMap(Class<K> keyType) {
+		super(WellBehavedMap.wrap(new EnumMap<K, V>(keyType)),
+				Maps.<V, K>newHashMapWithExpectedSize(keyType.getEnumConstants().length));
+		this.keyType = keyType;
+	}
+
+	// Overriding these 3 methods to show that values may be null (but not keys)
+
+	@Override
+	K checkKey(K key) {
+		return checkNotNull(key);
+	}
+
+	@Override
+	public V put(K key, @Nullable V value) {
+		return super.put(key, value);
+	}
+
+	@Override
+	public V forcePut(K key, @Nullable V value) {
+		return super.forcePut(key, value);
+	}
+
+	/** Returns the associated key type. */
+	public Class<K> keyType() {
+		return keyType;
+	}
+
+	/**
+	 * @serialData the key class, number of entries, first key, first value, second
+	 *             key, second value, and so on.
+	 */
+	@GwtIncompatible("java.io.ObjectOutputStream")
+	private void writeObject(ObjectOutputStream stream) throws IOException {
+		stream.defaultWriteObject();
+		stream.writeObject(keyType);
+		Serialization.writeMap(this, stream);
+	}
+
+	@SuppressWarnings("unchecked") // reading field populated by writeObject
+	@GwtIncompatible("java.io.ObjectInputStream")
+	private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException {
+		stream.defaultReadObject();
+		keyType = (Class<K>) stream.readObject();
+		setDelegates(WellBehavedMap.wrap(new EnumMap<K, V>(keyType)),
+				new HashMap<V, K>(keyType.getEnumConstants().length * 3 / 2));
+		Serialization.populateMap(this, stream);
+	}
+
+	@GwtIncompatible("only needed in emulated source.")
+	private static final long serialVersionUID = 0;
+}