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 import org.apache.directory.shared.ldap.cursor.Cursor;
023
024
025
026
027 /**
028 * A Cursor introducing new advance methods designed to reduce some
029 * inefficiencies encountered when scanning over Tuples.
030 *
031 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
032 * @version $$Rev$$
033 */
034 public interface TupleCursor<K,V> extends Cursor<Tuple<K,V>>
035 {
036 /**
037 * An alternative to calling before(Tuple) which often may require
038 * wrapping a key in a newly created Tuple object that may be unnecessary.
039 * This method behaves just like before(Tuple) except it advances to just
040 * before the first value of the key.
041 *
042 * @param key the key to advance just before
043 * @throws Exception if there are faults peforming this operation
044 */
045 void beforeKey( K key ) throws Exception;
046
047
048 /**
049 * An alternative to calling after(Tuple) which often may require
050 * wrapping a key in a newly created Tuple object that may be unnecessary.
051 * This method behaves just like after(Tuple) except it advances to just
052 * after the last value of the key.
053 *
054 * @param key the key to advance just after the last value
055 * @throws Exception if there are faults peforming this operation
056 */
057 void afterKey( K key ) throws Exception;
058
059
060 /**
061 * An alternative to calling before(Tuple) which often may require
062 * wrapping a key and a value in a newly created Tuple object that may be
063 * unnecessary. This method behaves just like before(Tuple) except it
064 * advances to just before the value of the key which may still be of the
065 * same key. This method will not be supported if duplicate keys are not
066 * supported. In this case an UnsupportedOperationException will be
067 * thrown.
068 *
069 * @param key the key of the value to advance just before
070 * @param value the value to advance just before
071 * @throws UnsupportedOperationException if duplicate keys not supporrted
072 * @throws Exception if there are faults peforming this operation
073 */
074 void beforeValue( K key, V value ) throws Exception;
075
076
077 /**
078 * An alternative to calling after(Tuple) which often may require
079 * wrapping a key and a value in a newly created Tuple object that may be
080 * unnecessary. This method behaves just like after(Tuple) except it
081 * advances to just after the value with the specified key. This method
082 * will not be supported if duplicate keys are not supported. In this
083 * case an UnsupportedOperationException will be thrown.
084 *
085 * @param key the key of the value to advance just after
086 * @param value the value to advance just after
087 * @throws UnsupportedOperationException if duplicate keys not supporrted
088 * @throws Exception if there are faults peforming this operation
089 */
090 void afterValue( K key, V value ) throws Exception;
091 }