01: /*
02: * Copyright 2003-2004 The Apache Software Foundation
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
10: * Unless required by applicable law or agreed to in writing, software
11: * distributed under the License is distributed on an "AS IS" BASIS,
12: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13: * See the License for the specific language governing permissions and
14: * limitations under the License.
15: */
16: package org.apache.commons.collections;
17:
18: /**
19: * Defines a map that allows bidirectional lookup between key and values
20: * and retains and provides access to an ordering.
21: * <p>
22: * Implementations should allow a value to be looked up from a key and
23: * a key to be looked up from a value with equal performance.
24: *
25: * @since Commons Collections 3.0
26: * @version $Revision: 155406 $ $Date: 2005-02-26 12:55:26 +0000 (Sat, 26 Feb 2005) $
27: *
28: * @author Stephen Colebourne
29: */
30: public interface OrderedBidiMap extends BidiMap, OrderedMap {
31:
32: /**
33: * Gets a view of this map where the keys and values are reversed.
34: * <p>
35: * Changes to one map will be visible in the other and vice versa.
36: * This enables both directions of the map to be accessed equally.
37: * <p>
38: * Implementations should seek to avoid creating a new object every time this
39: * method is called. See <code>AbstractMap.values()</code> etc. Calling this
40: * method on the inverse map should return the original.
41: * <p>
42: * Implementations must return an <code>OrderedBidiMap</code> instance,
43: * usually by forwarding to <code>inverseOrderedBidiMap()</code>.
44: *
45: * @return an inverted bidirectional map
46: */
47: public BidiMap inverseBidiMap();
48:
49: /**
50: * Gets a view of this map where the keys and values are reversed.
51: * <p>
52: * Changes to one map will be visible in the other and vice versa.
53: * This enables both directions of the map to be accessed equally.
54: * <p>
55: * Implementations should seek to avoid creating a new object every time this
56: * method is called. See <code>AbstractMap.values()</code> etc. Calling this
57: * method on the inverse map should return the original.
58: *
59: * @return an inverted bidirectional map
60: */
61: public OrderedBidiMap inverseOrderedBidiMap();
62:
63: }
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