Disconnect JournalSegmentReader from JournalReader

JournalSegmentReader is the only used by SegmentedJournalReader, which
is the actual implementation of JournalReader.

There is really no point in JournalSegmentReader to conform to the
public API, as not all elements are needed.

This disconnects JournalSegmentReader, eliminating getFirstIndex(), as
that is simply not called -- and was not conforming to the API anyway.

JIRA: CONTROLLER-2098
Change-Id: Icd802ee07207d4f6787e3bdb71e36e553f2010c3
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>

diff --git a/atomix-storage/src/main/java/io/atomix/storage/journal/JournalSegmentReader.java b/atomix-storage/src/main/java/io/atomix/storage/journal/JournalSegmentReader.java
index 2dddd9827633cb92b15cd30d1e3be245557c8fb0..03f7b3fd2aaedcc2d8dc1d43ebd2b63ed00869b0 100644 (file)
--- a/atomix-storage/src/main/java/io/atomix/storage/journal/JournalSegmentReader.java
+++ b/atomix-storage/src/main/java/io/atomix/storage/journal/JournalSegmentReader.java
@@ -14,8 +14,7 @@ import io.atomix.storage.journal.index.Position;
 import java.util.NoSuchElementException;
 import org.eclipse.jdt.annotation.Nullable;
 
-abstract sealed class JournalSegmentReader<E> implements JournalReader<E>
-        permits FileChannelJournalSegmentReader, MappedJournalSegmentReader {
+abstract sealed class JournalSegmentReader<E> permits FileChannelJournalSegmentReader, MappedJournalSegmentReader {
     final int maxEntrySize;
     private final JournalIndex index;
     final JournalSerdes namespace;
@@ -34,33 +33,49 @@ abstract sealed class JournalSegmentReader<E> implements JournalReader<E>
         firstIndex = segment.index();
     }
 
-    @Override
-    public final long getFirstIndex() {
-        return firstIndex;
-    }
-
-    @Override
-    public final long getCurrentIndex() {
+    /**
+     * Returns the current reader index.
+     *
+     * @return The current reader index.
+     */
+    final long getCurrentIndex() {
         return currentEntry != null ? currentEntry.index() : 0;
     }
 
-    @Override
-    public final Indexed<E> getCurrentEntry() {
+    /**
+     * Returns the last read entry.
+     *
+     * @return The last read entry.
+     */
+    final Indexed<E> getCurrentEntry() {
         return currentEntry;
     }
 
-    @Override
-    public final long getNextIndex() {
+    /**
+     * Returns the next reader index.
+     *
+     * @return The next reader index.
+     */
+    final long getNextIndex() {
         return currentEntry != null ? currentEntry.index() + 1 : firstIndex;
     }
 
-    @Override
-    public final boolean hasNext() {
+    /**
+     * Returns whether the reader has a next entry to read.
+     *
+     * @return Whether the reader has a next entry to read.
+     */
+    final boolean hasNext() {
         return nextEntry != null || (nextEntry = readNext()) != null;
     }
 
-    @Override
-    public final Indexed<E> next() {
+    /**
+     * Returns the next entry in the reader.
+     *
+     * @return The next entry in the reader.
+     * @throws UnsupportedOperationException if there is no such entry
+     */
+    final Indexed<E> next() {
         if (!hasNext()) {
             throw new NoSuchElementException();
         }
@@ -78,16 +93,22 @@ abstract sealed class JournalSegmentReader<E> implements JournalReader<E>
         return currentEntry;
     }
 
-    @Override
-    public final void reset() {
+    /**
+     * Resets the reader to the start of the segment.
+     */
+    final void reset() {
         currentEntry = null;
         nextEntry = null;
         setPosition(JournalSegmentDescriptor.BYTES);
         nextEntry = readNext();
     }
 
-    @Override
-    public final void reset(final long index) {
+    /**
+     * Resets the reader to the given index.
+     *
+     * @param index The index to which to reset the reader.
+     */
+    final void reset(final long index) {
         reset();
         Position position = this.index.lookup(index - 1);
         if (position != null) {
@@ -100,8 +121,10 @@ abstract sealed class JournalSegmentReader<E> implements JournalReader<E>
         }
     }
 
-    @Override
-    public final void close() {
+    /**
+     * Close this reader.
+     */
+    final void close() {
         segment.closeReader(this);
     }