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/*
* Copyright (C) 2007 Google Inc.
*
* 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.base.Nullable;
import java.util.EnumMap;
import java.util.HashMap;
import java.util.Map;
/**
* 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.
*
* @see EnumMap
* @see HashMap
* @author Mike Bostock
*/
public final class EnumHashBiMap, V>
extends StandardBiMap {
final Class keyType;
/**
* Constructs a new empty bimap using the specified key type, sized to contain
* an entry for every possible key.
*
* @param keyType the key type
* @throws NullPointerException if any argument is null
*/
public EnumHashBiMap(Class keyType) {
super(new EnumMap(keyType),
new HashMap(keyType.getEnumConstants().length * 3 / 2));
this.keyType = keyType;
}
/**
* Constructs a new bimap with the same mappings as the specified map. If the
* specified map is an {@code EnumHashBiMap} or an {@code EnumBiMap} instance,
* this constructor behaves identically to {@link
* #EnumHashBiMap(EnumHashBiMap)} or {@link #EnumHashBiMap(EnumHashBiMap)},
* respectively. Otherwise, the specified map must contain at least one
* mapping (in order to determine the new enum bimap's 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 EnumHashBiMap(Map map) {
this(EnumBiMap.inferKeyType(map));
putAll(map); // careful if we make this class non-final
}
/**
* Constructs a new bimap with the same key type as the specified map,
* initially containing the same mappings (if any).
*
* @param map the map whose mappings are to be placed in this map
*/
public EnumHashBiMap(EnumHashBiMap map) {
this(map.keyType);
putAll(map); // careful if we make this class non-final
}
/*
* Constructs a new bimap with the same key type as the specified map,
* initially containing the same mappings (if any).
*
* Note: This constructor has been commented out to work around Eclipse bug
* 179902. It should be restored when the bug has been fixed. In the meantime,
* the "(Map map)" overload will suffice. See:
* bug
* report.
*/
// @SuppressWarnings("unchecked")
// public EnumHashBiMap(EnumBiMap map) {
// this(map.keyType);
// putAll((Map) map); // careful if we make this class non-final
// }
// Overriding these two methods to show that values may be null (but not keys)
@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 keyType() {
return keyType;
}
}