import java.nio.BufferUnderflowException;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
+import java.nio.channels.FileChannel;
import java.util.zip.CRC32;
+import org.eclipse.jdt.annotation.NonNull;
/**
* Segment writer.
*
* @author <a href="http://github.com/kuujo">Jordan Halterman</a>
*/
-class MappedJournalSegmentWriter<E> implements JournalWriter<E> {
- private final MappedByteBuffer mappedBuffer;
+final class MappedJournalSegmentWriter<E> extends JournalSegmentWriter<E> {
+ private final @NonNull MappedByteBuffer mappedBuffer;
private final ByteBuffer buffer;
- private final JournalSegment<E> segment;
- private final int maxEntrySize;
- private final JournalIndex index;
- private final JournalSerdes namespace;
- private final long firstIndex;
+
private Indexed<E> lastEntry;
MappedJournalSegmentWriter(
- MappedByteBuffer buffer,
+ FileChannel channel,
JournalSegment<E> segment,
int maxEntrySize,
JournalIndex index,
JournalSerdes namespace) {
- this.mappedBuffer = buffer;
- this.buffer = buffer.slice();
- this.segment = segment;
- this.maxEntrySize = maxEntrySize;
- this.index = index;
- this.namespace = namespace;
- this.firstIndex = segment.index();
+ super(channel, segment, maxEntrySize, index, namespace);
+ mappedBuffer = mapBuffer(channel, maxSegmentSize);
+ buffer = mappedBuffer.slice();
reset(0);
}
- /**
- * Returns the mapped buffer underlying the segment writer.
- *
- * @return the mapped buffer underlying the segment writer
- */
- MappedByteBuffer buffer() {
+ MappedJournalSegmentWriter(JournalSegmentWriter<E> previous, int position) {
+ super(previous);
+ mappedBuffer = mapBuffer(channel, maxSegmentSize);
+ buffer = mappedBuffer.slice();
+ lastEntry = previous.getLastEntry();
+ buffer.position(position);
+ }
+
+ private static @NonNull MappedByteBuffer mapBuffer(FileChannel channel, int maxSegmentSize) {
+ try {
+ return channel.map(FileChannel.MapMode.READ_WRITE, 0, maxSegmentSize);
+ } catch (IOException e) {
+ throw new StorageException(e);
+ }
+ }
+
+ @Override
+ @NonNull MappedByteBuffer buffer() {
return mappedBuffer;
}
@Override
- public void reset(long index) {
+ MappedJournalSegmentWriter<E> toMapped() {
+ return this;
+ }
+
+ @Override
+ FileChannelJournalSegmentWriter<E> toFileChannel() {
+ final int position = buffer.position();
+ close();
+ return new FileChannelJournalSegmentWriter<>(this, position);
+ }
+
+ @Override
+ void reset(long index) {
long nextIndex = firstIndex;
// Clear the buffer indexes.
// Read the checksum of the entry.
final long checksum = buffer.getInt() & 0xFFFFFFFFL;
+ // Slice off the entry's bytes
+ final ByteBuffer entryBytes = buffer.slice();
+ entryBytes.limit(length);
+
// Compute the checksum for the entry bytes.
final CRC32 crc32 = new CRC32();
- ByteBuffer slice = buffer.slice();
- slice.limit(length);
- crc32.update(slice);
-
- // If the stored checksum equals the computed checksum, return the entry.
- if (checksum == crc32.getValue()) {
- slice.rewind();
- final E entry = namespace.deserialize(slice);
- lastEntry = new Indexed<>(nextIndex, entry, length);
- this.index.index(nextIndex, position);
- nextIndex++;
- } else {
+ crc32.update(entryBytes);
+
+ // If the stored checksum does not equal the computed checksum, do not proceed further
+ if (checksum != crc32.getValue()) {
break;
}
+ entryBytes.rewind();
+ final E entry = namespace.deserialize(entryBytes);
+ lastEntry = new Indexed<>(nextIndex, entry, length);
+ this.index.index(nextIndex, position);
+ nextIndex++;
+
// Update the current position for indexing.
position = buffer.position() + length;
buffer.position(position);
}
@Override
- public long getLastIndex() {
- return lastEntry != null ? lastEntry.index() : segment.index() - 1;
- }
-
- @Override
- public Indexed<E> getLastEntry() {
+ Indexed<E> getLastEntry() {
return lastEntry;
}
@Override
- public long getNextIndex() {
+ long getNextIndex() {
if (lastEntry != null) {
return lastEntry.index() + 1;
} else {
}
}
- @Override
- public void append(Indexed<E> entry) {
- final long nextIndex = getNextIndex();
-
- // If the entry's index is greater than the next index in the segment, skip some entries.
- if (entry.index() > nextIndex) {
- throw new IndexOutOfBoundsException("Entry index is not sequential");
- }
-
- // If the entry's index is less than the next index, truncate the segment.
- if (entry.index() < nextIndex) {
- truncate(entry.index() - 1);
- }
- append(entry.entry());
- }
-
@Override
@SuppressWarnings("unchecked")
- public <T extends E> Indexed<T> append(T entry) {
+ <T extends E> Indexed<T> append(T entry) {
// Store the entry index.
final long index = getNextIndex();
}
@Override
- public void commit(long index) {
-
- }
-
- @Override
- public void truncate(long index) {
+ void truncate(long index) {
// If the index is greater than or equal to the last index, skip the truncate.
if (index >= getLastIndex()) {
return;
// Truncate the index.
this.index.truncate(index);
- if (index < segment.index()) {
+ if (index < firstIndex) {
// Reset the writer to the first entry.
buffer.position(JournalSegmentDescriptor.BYTES);
} else {
}
@Override
- public void flush() {
+ void flush() {
mappedBuffer.force();
}
@Override
- public void close() {
+ void close() {
flush();
try {
BufferCleaner.freeBuffer(mappedBuffer);
Code Review / controller.git / blobdiff