JournalIndex.truncate() should return last entry

[controller.git] / atomix-storage / src / main / java / io / atomix / storage / journal / index / SparseJournalIndex.java

diff --git a/atomix-storage/src/main/java/io/atomix/storage/journal/index/SparseJournalIndex.java b/atomix-storage/src/main/java/io/atomix/storage/journal/index/SparseJournalIndex.java
index 5fe4280eb00207a9b3b9f719162318cda8eb4489..2b317362c57f3ee6b7637e3fedecbff22e49276d 100644 (file)
--- a/atomix-storage/src/main/java/io/atomix/storage/journal/index/SparseJournalIndex.java
+++ b/atomix-storage/src/main/java/io/atomix/storage/journal/index/SparseJournalIndex.java
@@ -1,5 +1,6 @@
 /*
  * Copyright 2018-2022 Open Networking Foundation and others.  All rights reserved.
+ * Copyright (c) 2024 PANTHEON.tech, s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,36 +16,40 @@
  */
 package io.atomix.storage.journal.index;
 
-import java.util.Map;
 import java.util.TreeMap;
 
 /**
- * Sparse index.
+ * A {@link JournalIndex} maintaining target density.
  */
-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);
+public final 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() {
+        density = MIN_DENSITY;
+    }
+
+    public SparseJournalIndex(final double density) {
+        this.density = (int) Math.ceil(MIN_DENSITY / (density * MIN_DENSITY));
+    }
+
+    @Override
+    public void index(final long index, final int position) {
+        if (index % density == 0) {
+            positions.put(index, position);
+        }
+    }
+
+    @Override
+    public Position lookup(final long index) {
+        return Position.ofNullable(positions.floorEntry(index));
+    }
+
+    @Override
+    public Position truncate(final long index) {
+        positions.tailMap(index, false).clear();
+        return Position.ofNullable(positions.lastEntry());
     }
-  }
-
-  @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();
-  }
 }