*/
package io.atomix.storage.journal;
-import static java.util.Objects.requireNonNull;
-
import com.google.common.annotations.VisibleForTesting;
-import com.google.common.base.MoreObjects;
import java.io.IOException;
import java.nio.ByteBuffer;
-import java.nio.channels.FileChannel;
-import java.nio.file.Path;
-import java.nio.file.StandardOpenOption;
+import java.nio.channels.ReadableByteChannel;
import org.eclipse.jdt.annotation.NonNull;
+import org.eclipse.jdt.annotation.Nullable;
/**
* Stores information about a {@link JournalSegment} of the log.
+ *
* <p>
* The segment descriptor manages metadata related to a single segment of the log. Descriptors are stored within the
* first {@code 64} bytes of each segment in the following order:
* <ul>
- * <li>{@code id} (64-bit signed integer) - A unique segment identifier. This is a monotonically increasing number within
- * each log. Segments with in-sequence identifiers should contain in-sequence indexes.</li>
- * <li>{@code index} (64-bit signed integer) - The effective first index of the segment. This indicates the index at which
- * the first entry should be written to the segment. Indexes are monotonically increasing thereafter.</li>
- * <li>{@code version} (64-bit signed integer) - The version of the segment. Versions are monotonically increasing
- * starting at {@code 1}. Versions will only be incremented whenever the segment is rewritten to another memory/disk
- * space, e.g. after log compaction.</li>
- * <li>{@code maxSegmentSize} (32-bit unsigned integer) - The maximum number of bytes allowed in the segment.</li>
- * <li>{@code maxEntries} (32-bit signed integer) - The total number of expected entries in the segment. This is the final
- * number of entries allowed within the segment both before and after compaction. This entry count is used to determine
- * the count of internal indexing and deduplication facilities.</li>
- * <li>{@code updated} (64-bit signed integer) - The last update to the segment in terms of milliseconds since the epoch.
- * When the segment is first constructed, the {@code updated} time is {@code 0}. Once all entries in the segment have
- * been committed, the {@code updated} time should be set to the current time. Log compaction should not result in a
- * change to {@code updated}.</li>
- * <li>{@code locked} (8-bit boolean) - A boolean indicating whether the segment is locked. Segments will be locked once
- * all entries have been committed to the segment. The lock state of each segment is used to determine log compaction
- * and recovery behavior.</li>
+ * <li>{@code id} (64-bit signed integer) - A unique segment identifier. This is a monotonically increasing number
+ * within each log. Segments with in-sequence identifiers should contain in-sequence indexes.</li>
+ * <li>{@code index} (64-bit signed integer) - The effective first index of the segment. This indicates the index at
+ * which the first entry should be written to the segment. Indexes are monotonically increasing thereafter.</li>
+ * <li>{@code version} (64-bit signed integer) - The version of the segment. Versions are monotonically increasing
+ * starting at {@code 1}. Versions will only be incremented whenever the segment is rewritten to another
+ * memory/disk space, e.g. after log compaction.</li>
+ * <li>{@code maxSegmentSize} (32-bit unsigned integer) - The maximum number of bytes allowed in the segment.</li>
+ * <li>{@code maxEntries} (32-bit signed integer) - The total number of expected entries in the segment. This is the
+ * final number of entries allowed within the segment both before and after compaction. This entry count is used
+ * to determine the count of internal indexing and deduplication facilities.</li>
+ * <li>{@code updated} (64-bit signed integer) - The last update to the segment in terms of milliseconds since the
+ * epoch.
+ * When the segment is first constructed, the {@code updated} time is {@code 0}. Once all entries in the segment
+ * have been committed, the {@code updated} time should be set to the current time. Log compaction should not
+ * result in a change to {@code updated}.</li>
+ * <li>{@code locked} (8-bit boolean) - A boolean indicating whether the segment is locked. Segments will be locked
+ * once all entries have been committed to the segment. The lock state of each segment is used to determine log
+ * compaction and recovery behavior.</li>
* </ul>
* The remainder of the 64 segment header bytes are reserved for future metadata.
*
* @author <a href="http://github.com/kuujo">Jordan Halterman</a>
*/
-public final class JournalSegmentDescriptor {
- public static final int BYTES = 64;
-
- // Current segment version.
- @VisibleForTesting
- static final int VERSION = 1;
-
- // The lengths of each field in the header.
- private static final int VERSION_LENGTH = Integer.BYTES; // 32-bit signed integer
- private static final int ID_LENGTH = Long.BYTES; // 64-bit signed integer
- private static final int INDEX_LENGTH = Long.BYTES; // 64-bit signed integer
- private static final int MAX_SIZE_LENGTH = Integer.BYTES; // 32-bit signed integer
- private static final int MAX_ENTRIES_LENGTH = Integer.BYTES; // 32-bit signed integer
- private static final int UPDATED_LENGTH = Long.BYTES; // 64-bit signed integer
-
- // The positions of each field in the header.
- private static final int VERSION_POSITION = 0; // 0
- private static final int ID_POSITION = VERSION_POSITION + VERSION_LENGTH; // 4
- private static final int INDEX_POSITION = ID_POSITION + ID_LENGTH; // 12
- private static final int MAX_SIZE_POSITION = INDEX_POSITION + INDEX_LENGTH; // 20
- private static final int MAX_ENTRIES_POSITION = MAX_SIZE_POSITION + MAX_SIZE_LENGTH; // 24
- private static final int UPDATED_POSITION = MAX_ENTRIES_POSITION + MAX_ENTRIES_LENGTH; // 28
-
- /**
- * Returns a descriptor builder.
- * <p>
- * The descriptor builder will write segment metadata to a {@code 48} byte in-memory buffer.
- *
- * @return The descriptor builder.
- */
- public static Builder builder() {
- return new Builder(ByteBuffer.allocate(BYTES));
- }
-
- /**
- * Returns a descriptor builder for the given descriptor buffer.
- *
- * @param buffer The descriptor buffer.
- * @return The descriptor builder.
- * @throws NullPointerException if {@code buffer} is null
- */
- public static Builder builder(ByteBuffer buffer) {
- return new Builder(buffer);
- }
-
- private final ByteBuffer buffer;
- private final int version;
- private final long id;
- private final long index;
- private final int maxSegmentSize;
- private final int maxEntries;
- private volatile long updated;
- private volatile boolean locked;
-
- /**
- * @throws NullPointerException if {@code buffer} is null
- */
- public JournalSegmentDescriptor(ByteBuffer buffer) {
- this.buffer = buffer;
- this.version = buffer.getInt();
- this.id = buffer.getLong();
- this.index = buffer.getLong();
- this.maxSegmentSize = buffer.getInt();
- this.maxEntries = buffer.getInt();
- this.updated = buffer.getLong();
- this.locked = buffer.get() == 1;
- }
-
- /**
- * Read a JournalSegmentDescriptor from a {@link Path}.
- *
- * @param path path to read from
- * @return A {@link JournalSegmentDescriptor}
- * @throws IOException if an I/O error occurs or there is not enough data
- */
- public static @NonNull JournalSegmentDescriptor readFrom(final Path path) throws IOException {
- try (var channel = FileChannel.open(path, StandardOpenOption.READ)) {
- final var buffer = ByteBuffer.allocate(BYTES);
- final var readBytes = channel.read(buffer);
- if (readBytes != BYTES) {
- throw new IOException("Need " + BYTES + " bytes, only " + readBytes + " available");
- }
- return new JournalSegmentDescriptor(buffer.flip());
- }
- }
-
- /**
- * Returns the segment version.
- * <p>
- * Versions are monotonically increasing starting at {@code 1}.
- *
- * @return The segment version.
- */
- public int version() {
- return version;
- }
-
- /**
- * Returns the segment identifier.
- * <p>
- * The segment ID is a monotonically increasing number within each log. Segments with in-sequence identifiers should
- * contain in-sequence indexes.
- *
- * @return The segment identifier.
- */
- public long id() {
- return id;
- }
-
- /**
- * Returns the segment index.
- * <p>
- * The index indicates the index at which the first entry should be written to the segment. Indexes are monotonically
- * increasing thereafter.
- *
- * @return The segment index.
- */
- public long index() {
- return index;
- }
+public record JournalSegmentDescriptor(
+ int version,
+ long id,
+ long index,
+ int maxSegmentSize,
+ int maxEntries,
+ long updated,
+ boolean locked) {
+ public static final int BYTES = 64;
- /**
- * Returns the maximum count of the segment.
- *
- * @return The maximum allowed count of the segment.
- */
- public int maxSegmentSize() {
- return maxSegmentSize;
- }
+ // Current segment version.
+ @VisibleForTesting
+ static final int VERSION = 1;
- /**
- * Returns the maximum number of entries allowed in the segment.
- *
- * @return The maximum number of entries allowed in the segment.
- */
- public int maxEntries() {
- return maxEntries;
- }
-
- /**
- * Returns last time the segment was updated.
- * <p>
- * When the segment is first constructed, the {@code updated} time is {@code 0}. Once all entries in the segment have
- * been committed, the {@code updated} time should be set to the current time. Log compaction should not result in a
- * change to {@code updated}.
- *
- * @return The last time the segment was updated in terms of milliseconds since the epoch.
- */
- public long updated() {
- return updated;
- }
+ /**
+ * Read a JournalSegmentDescriptor from a {@link ReadableByteChannel}.
+ *
+ * @param channel channel to read from
+ * @return A {@link JournalSegmentDescriptor}
+ * @throws IOException if an I/O error occurs or there is not enough data
+ */
+ public static @NonNull JournalSegmentDescriptor readFrom(final ReadableByteChannel channel) throws IOException {
+ final var buffer = ByteBuffer.allocate(BYTES);
+ final var read = channel.read(buffer);
+ if (read != BYTES) {
+ throw new IOException("Need " + BYTES + " bytes, only " + read + " available");
+ }
- /**
- * Writes an update to the descriptor.
- */
- public void update(long timestamp) {
- if (!locked) {
- buffer.putLong(UPDATED_POSITION, timestamp);
- this.updated = timestamp;
+ buffer.flip();
+ return new JournalSegmentDescriptor(
+ buffer.getInt(),
+ buffer.getLong(),
+ buffer.getLong(),
+ buffer.getInt(),
+ buffer.getInt(),
+ buffer.getLong(),
+ buffer.get() == 1);
}
- }
- /**
- * Copies the segment to a new buffer.
- */
- JournalSegmentDescriptor copyTo(ByteBuffer buffer) {
- buffer.putInt(version);
- buffer.putLong(id);
- buffer.putLong(index);
- buffer.putInt(maxSegmentSize);
- buffer.putInt(maxEntries);
- buffer.putLong(updated);
- buffer.put(locked ? (byte) 1 : (byte) 0);
- return this;
- }
+ /**
+ * Returns the segment version.
+ *
+ * <p>
+ * Versions are monotonically increasing starting at {@code 1}.
+ *
+ * @return The segment version.
+ */
+ public int version() {
+ return version;
+ }
- @Override
- public String toString() {
- return MoreObjects.toStringHelper(this)
- .add("version", version)
- .add("id", id)
- .add("index", index)
- .add("updated", updated)
- .toString();
- }
+ /**
+ * Returns the segment identifier.
+ *
+ * <p>
+ * The segment ID is a monotonically increasing number within each log. Segments with in-sequence identifiers should
+ * contain in-sequence indexes.
+ *
+ * @return The segment identifier.
+ */
+ public long id() {
+ return id;
+ }
- /**
- * Segment descriptor builder.
- */
- public static class Builder {
- private final ByteBuffer buffer;
+ /**
+ * Returns the segment index.
+ *
+ * <p>
+ * The index indicates the index at which the first entry should be written to the segment. Indexes are
+ * monotonically increasing thereafter.
+ *
+ * @return The segment index.
+ */
+ public long index() {
+ return index;
+ }
- private Builder(ByteBuffer buffer) {
- this.buffer = requireNonNull(buffer, "buffer cannot be null");
- buffer.putInt(VERSION_POSITION, VERSION);
+ /**
+ * Returns the maximum count of the segment.
+ *
+ * @return The maximum allowed count of the segment.
+ */
+ public int maxSegmentSize() {
+ return maxSegmentSize;
}
/**
- * Sets the segment identifier.
+ * Returns the maximum number of entries allowed in the segment.
*
- * @param id The segment identifier.
- * @return The segment descriptor builder.
+ * @return The maximum number of entries allowed in the segment.
*/
- public Builder withId(long id) {
- buffer.putLong(ID_POSITION, id);
- return this;
+ public int maxEntries() {
+ return maxEntries;
}
/**
- * Sets the segment index.
+ * Returns last time the segment was updated.
*
- * @param index The segment starting index.
- * @return The segment descriptor builder.
+ * <p>
+ * When the segment is first constructed, the {@code updated} time is {@code 0}. Once all entries in the segment
+ * have been committed, the {@code updated} time should be set to the current time. Log compaction should not result
+ * in a change to {@code updated}.
+ *
+ * @return The last time the segment was updated in terms of milliseconds since the epoch.
*/
- public Builder withIndex(long index) {
- buffer.putLong(INDEX_POSITION, index);
- return this;
+ public long updated() {
+ return updated;
}
/**
- * Sets maximum count of the segment.
+ * Returns this segment as an array of bytes.
*
- * @param maxSegmentSize The maximum count of the segment.
- * @return The segment descriptor builder.
+ * @return bytes
*/
- public Builder withMaxSegmentSize(int maxSegmentSize) {
- buffer.putInt(MAX_SIZE_POSITION, maxSegmentSize);
- return this;
+ byte @NonNull [] toArray() {
+ final var bytes = new byte[BYTES];
+ ByteBuffer.wrap(bytes)
+ .putInt(version)
+ .putLong(id)
+ .putLong(index)
+ .putInt(maxSegmentSize)
+ .putInt(maxEntries)
+ .putLong(updated)
+ .put(locked ? (byte) 1 : (byte) 0);
+ return bytes;
}
/**
- * Sets the maximum number of entries in the segment.
+ * Returns a descriptor builder.
+ *
+ * <p>
+ * The descriptor builder will write segment metadata to a {@code 48} byte in-memory buffer.
*
- * @param maxEntries The maximum number of entries in the segment.
- * @return The segment descriptor builder.
- * @deprecated since 3.0.2
+ * @return The descriptor builder.
*/
- @Deprecated
- public Builder withMaxEntries(int maxEntries) {
- buffer.putInt(MAX_ENTRIES_POSITION, maxEntries);
- return this;
+ public static Builder builder() {
+ return builder(VERSION);
}
/**
- * Builds the segment descriptor.
+ * Returns a descriptor builder for the given descriptor buffer.
*
- * @return The built segment descriptor.
+ * @param version version to build
+ * @return The descriptor builder.
+ * @throws NullPointerException if {@code buffer} is null
*/
- public JournalSegmentDescriptor build() {
- buffer.rewind();
- return new JournalSegmentDescriptor(buffer);
+ public static Builder builder(final int version) {
+ return new Builder(version);
+ }
+
+ /**
+ * Segment descriptor builder.
+ */
+ public static final class Builder {
+ private final int version;
+
+ private Long id;
+ private Long index;
+ private Integer maxSegmentSize;
+ private Integer maxEntries;
+ private Long updated;
+
+ Builder(final int version) {
+ this.version = version;
+ }
+
+ /**
+ * Sets the segment identifier.
+ *
+ * @param id The segment identifier.
+ * @return The segment descriptor builder.
+ */
+ @SuppressWarnings("checkstyle:hiddenField")
+ public Builder withId(final long id) {
+ this.id = id;
+ return this;
+ }
+
+ /**
+ * Sets the segment index.
+ *
+ * @param index The segment starting index.
+ * @return The segment descriptor builder.
+ */
+ @SuppressWarnings("checkstyle:hiddenField")
+ public Builder withIndex(final long index) {
+ this.index = index;
+ return this;
+ }
+
+ /**
+ * Sets maximum count of the segment.
+ *
+ * @param maxSegmentSize The maximum count of the segment.
+ * @return The segment descriptor builder.
+ */
+ @SuppressWarnings("checkstyle:hiddenField")
+ public Builder withMaxSegmentSize(final int maxSegmentSize) {
+ this.maxSegmentSize = maxSegmentSize;
+ return this;
+ }
+
+ /**
+ * Sets the maximum number of entries in the segment.
+ *
+ * @param maxEntries The maximum number of entries in the segment.
+ * @return The segment descriptor builder.
+ * @deprecated since 3.0.2
+ */
+ @Deprecated
+ @SuppressWarnings("checkstyle:hiddenField")
+ public Builder withMaxEntries(final int maxEntries) {
+ this.maxEntries = maxEntries;
+ return this;
+ }
+
+ /**
+ * Sets updated timestamp.
+ *
+ * @param updated Epoch milliseconds
+ * @return The segment descriptor builder.
+ */
+ @SuppressWarnings("checkstyle:hiddenField")
+ public Builder withUpdated(final long updated) {
+ this.updated = updated;
+ return this;
+ }
+
+ /**
+ * Builds the segment descriptor.
+ *
+ * @return The built segment descriptor.
+ */
+ public JournalSegmentDescriptor build() {
+ return new JournalSegmentDescriptor(version,
+ checkSet(id, "id"),
+ checkSet(index, "index"),
+ checkSet(maxSegmentSize, "maxSegmentSize"),
+ checkSet(maxEntries, "maxEntries"),
+ checkSet(updated, "updated"),
+ false);
+ }
+
+ private static <T> @NonNull T checkSet(final @Nullable T obj, final String name) {
+ if (obj != null) {
+ return obj;
+ }
+ throw new IllegalArgumentException(name + " not set");
+ }
}
- }
}
Code Review / controller.git / blobdiff