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