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package org.apache.commons.collections;

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.
Author:
Stephen Colebourne
Since:
Commons Collections 3.0
Version:
$Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $/**
 * Defines a map that allows bidirectional lookup between key and values
 * and retains and provides access to an ordering.
 * <p>
 * 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.
 * 
 * @since Commons Collections 3.0
 * @version $Revision: 646777 $ $Date: 2008-04-10 14:33:15 +0200 (Thu, 10 Apr 2008) $
 *
 * @author Stephen Colebourne
 */
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().
Returns:
an inverted bidirectional map/**
     * Gets a view of this map where the keys and values are reversed.
     * <p>
     * Changes to one map will be visible in the other and vice versa.
     * This enables both directions of the map to be accessed equally.
     * <p>
     * Implementations should seek to avoid creating a new object every time this
     * method is called. See <code>AbstractMap.values()</code> etc. Calling this
     * method on the inverse map should return the original.
     * <p>
     * Implementations must return an <code>OrderedBidiMap</code> instance,
     * usually by forwarding to <code>inverseOrderedBidiMap()</code>.
     *
     * @return an inverted bidirectional map
     */
    public BidiMap inverseBidiMap();
    
    
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.
Returns:
an inverted bidirectional map/**
     * Gets a view of this map where the keys and values are reversed.
     * <p>
     * Changes to one map will be visible in the other and vice versa.
     * This enables both directions of the map to be accessed equally.
     * <p>
     * Implementations should seek to avoid creating a new object every time this
     * method is called. See <code>AbstractMap.values()</code> etc. Calling this
     * method on the inverse map should return the original.
     *
     * @return an inverted bidirectional map
     */
    public OrderedBidiMap inverseOrderedBidiMap();
    
}