2 * Copyright 2018-present Open Networking Foundation
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
16 package io.atomix.storage.journal.index;
19 import java.util.TreeMap;
24 public class SparseJournalIndex implements JournalIndex {
25 private static final int MIN_DENSITY = 1000;
26 private final int density;
27 private final TreeMap<Long, Integer> positions = new TreeMap<>();
29 public SparseJournalIndex(double density) {
30 this.density = (int) Math.ceil(MIN_DENSITY / (density * MIN_DENSITY));
34 public void index(long index, int position) {
35 if (index % density == 0) {
36 positions.put(index, position);
41 public Position lookup(long index) {
42 Map.Entry<Long, Integer> entry = positions.floorEntry(index);
43 return entry != null ? new Position(entry.getKey(), entry.getValue()) : null;
47 public void truncate(long index) {
48 positions.tailMap(index, false).clear();