2 * Copyright 2018-2022 Open Networking Foundation and others. All rights reserved.
3 * Copyright (c) 2024 PANTHEON.tech, s.r.o.
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
9 * http://www.apache.org/licenses/LICENSE-2.0
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
17 package io.atomix.storage.journal.index;
19 import org.eclipse.jdt.annotation.Nullable;
22 * Index of a particular JournalSegment.
24 public interface JournalIndex {
26 * Adds an entry for the given index at the given position.
28 * @param index the index for which to add the entry
29 * @param position the position of the given index
31 void index(long index, int position);
34 * Looks up the position of the given index.
36 * @param index the index to lookup
37 * @return the position of the given index or a lesser index, or {@code null}
39 @Nullable Position lookup(long index);
42 * Truncates the index to the given index and returns its position, if available.
44 * @param index the index to which to truncate the index, or {@code null}
45 * @return the position of the given index or a lesser index, or {@code null}
47 @Nullable Position truncate(long index);