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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.commons.collections4;
/**
* Defines a map that allows bidirectional lookup between key and values
* and retains and provides access to an ordering.
*
* Implementations should allow a value to be looked up from a key and
* a key to be looked up from a value with equal performance.
*
* @param the type of the keys in the map
* @param the type of the values in the map
*
* @since 3.0
*/
public interface OrderedBidiMap extends BidiMap, OrderedMap {
/**
* Gets a view of this map where the keys and values are reversed.
*
* Changes to one map will be visible in the other and vice versa.
* This enables both directions of the map to be accessed equally.
*
* Implementations should seek to avoid creating a new object every time this
* method is called. See AbstractMap.values() etc. Calling this
* method on the inverse map should return the original.
*
* Implementations must return an OrderedBidiMap instance,
* usually by forwarding to inverseOrderedBidiMap().
*
* @return an inverted bidirectional map
*/
@Override
OrderedBidiMap inverseBidiMap();
}