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 */ 020 package org.apache.directory.server.xdbm; 021 022 023 import org.apache.directory.shared.ldap.cursor.Cursor; 024 025 026 /** 027 * A Cursor introducing new advance methods designed to reduce some 028 * inefficiencies encountered when scanning over Tuples. 029 * 030 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 031 * @version $$Rev$$ 032 */ 033 public interface TupleCursor<K, V> extends Cursor<Tuple<K, V>> 034 { 035 /** 036 * An alternative to calling before(Tuple) which often may require 037 * wrapping a key in a newly created Tuple object that may be unnecessary. 038 * This method behaves just like before(Tuple) except it advances to just 039 * before the first value of the key. 040 * 041 * @param key the key to advance just before 042 * @throws Exception if there are faults peforming this operation 043 */ 044 void beforeKey( K key ) throws Exception; 045 046 047 /** 048 * An alternative to calling after(Tuple) which often may require 049 * wrapping a key in a newly created Tuple object that may be unnecessary. 050 * This method behaves just like after(Tuple) except it advances to just 051 * after the last value of the key. 052 * 053 * @param key the key to advance just after the last value 054 * @throws Exception if there are faults peforming this operation 055 */ 056 void afterKey( K key ) throws Exception; 057 058 059 /** 060 * An alternative to calling before(Tuple) which often may require 061 * wrapping a key and a value in a newly created Tuple object that may be 062 * unnecessary. This method behaves just like before(Tuple) except it 063 * advances to just before the value of the key which may still be of the 064 * same key. This method will not be supported if duplicate keys are not 065 * supported. In this case an UnsupportedOperationException will be 066 * thrown. 067 * 068 * @param key the key of the value to advance just before 069 * @param value the value to advance just before 070 * @throws UnsupportedOperationException if duplicate keys not supporrted 071 * @throws Exception if there are faults peforming this operation 072 */ 073 void beforeValue( K key, V value ) throws Exception; 074 075 076 /** 077 * An alternative to calling after(Tuple) which often may require 078 * wrapping a key and a value in a newly created Tuple object that may be 079 * unnecessary. This method behaves just like after(Tuple) except it 080 * advances to just after the value with the specified key. This method 081 * will not be supported if duplicate keys are not supported. In this 082 * case an UnsupportedOperationException will be thrown. 083 * 084 * @param key the key of the value to advance just after 085 * @param value the value to advance just after 086 * @throws UnsupportedOperationException if duplicate keys not supporrted 087 * @throws Exception if there are faults peforming this operation 088 */ 089 void afterValue( K key, V value ) throws Exception; 090 }