001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *  
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *  
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License. 
018 *  
019 */
020package org.apache.directory.server.core.partition.impl.btree;
021
022
023import java.io.Serializable;
024
025import org.apache.directory.api.ldap.model.schema.comparators.SerializableComparator;
026
027
028/**
029 * Used to compare the sorting order of binary data.
030 * 
031 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
032 */
033public interface TupleComparator<K, V> extends Serializable
034{
035    /**
036     * Gets the comparator used to compare keys.  May be null in which
037     * case the compareKey method will throw an UnsupportedOperationException.
038     *
039     * @return the comparator for comparing keys.
040     */
041    SerializableComparator<K> getKeyComparator();
042
043
044    /**
045     * Gets the binary comparator used to compare valuess.  May be null in which
046     * case the compareValue method will throw an UnsupportedOperationException.
047     *
048     * @return the binary comparator for comparing values.
049     */
050    SerializableComparator<V> getValueComparator();
051
052
053    /**
054     * Compares key Object to determine their sorting order returning a
055     * value = to, &lt; or &gt; than 0.
056     *
057     * @param key1 the first key to compare
058     * @param key2 the other key to compare to the first
059     * @return 0 if both are equal, a negative value less than 0 if the first
060     * is less than the second, or a postive value if the first is greater than
061     * the second byte array.
062     */
063    int compareKey( K key1, K key2 );
064
065
066    /**
067     * Comparse value Objects to determine their sorting order returning a
068     * value = to, &lt; or &gt; than 0.
069     *
070     * @param value1 the first value to compare
071     * @param value2 the other value to compare to the first
072     * @return 0 if both are equal, a negative value less than 0 if the first
073     * is less than the second, or a postive value if the first is greater than
074     * the second Object.
075     */
076    int compareValue( V value1, V value2 );
077}