/*******************************************************************************
* Copyright 2010 Cees De Groot, Alex Boisvert, Jan Kotek
*
* 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 de.mxro.thrd.jdbm2V22;
/**
*
* Extract secondary key from record in primary map.
*
* @author Jan Kotek
*
* @param <A> Type of secondary key
* @param <K> Type of primary key
* @param <V> Type of primary value
*/
public interface SecondaryKeyExtractor<A,K,V> {
/**
* Extracts secondary key from primary map
*
* @param key key in primary table
* @param value value in primary table
* @return secondary key or null to skip this record
*/
A extractSecondaryKey(K key, V value);
}