public class Snapshot {
    private final Integer version;

    private final long id;

    private final long schemaId;

    // a manifest list recording all changes from the previous snapshots
    private final String baseManifestList;

    // a manifest list recording all new changes occurred in this snapshot
    // for faster expire and streaming reads
    private final String deltaManifestList;

    // a manifest list recording all changelog produced in this snapshot
    // null if no changelog is produced, or for paimon <= 0.2
    private final String changelogManifestList;

    // a manifest recording all index files of this table
    // null if no index file
    private final String indexManifest;

    private final String commitUser;

    // Mainly for snapshot deduplication.
    //
    // If multiple snapshots have the same commitIdentifier, reading from any of these snapshots
    // must produce the same table.
    //
    // If snapshot A has a smaller commitIdentifier than snapshot B, then snapshot A must be
    // committed before snapshot B, and thus snapshot A must contain older records than snapshot B.
    private final long commitIdentifier;

    private final CommitKind commitKind;

    private final long timeMillis;

    private final Map<Integer, Long> logOffsets;

    // record count of all changes occurred in this snapshot
    // null for paimon <= 0.3
    private final Long totalRecordCount;

    // record count of all new changes occurred in this snapshot
    // null for paimon <= 0.3
    private final Long deltaRecordCount;

    // record count of all changelog produced in this snapshot
    // null for paimon <= 0.3
    private final Long changelogRecordCount;

    // watermark for input records
    // null for paimon <= 0.3
    // null if there is no watermark in new committing, and the previous snapshot does not have a
    // watermark
    private final Long watermark;
}

public class Schema {
    private final List<DataField> fields;
    private final List<String> partitionKeys;
    private final List<String> primaryKeys;
    private final Map<String, String> options;
    private final String comment;
}

public enum FileKind {
    ADD((byte) 0),
    DELETE((byte) 1);
}

public class IndexFileMeta {
    private final String indexType;
    private final String fileName;
    private final long fileSize;
    private final long rowCount;
}

public class IndexManifestEntry {
    private final FileKind kind;
    private final BinaryRow partition;
    private final int bucket;
    private final IndexFileMeta indexFile;
}

public class ManifestFileMeta {
    private final String fileName;
    private final long fileSize;
    private final long numAddedFiles;
    private final long numDeletedFiles;
    private final BinaryTableStats partitionStats;
    private final long schemaId;
}

public class ManifestCommittable { ///Manifest commit message
    private final long identifier;
    @Nullable private final Long watermark;
    private final Map<Integer, Long> logOffsets;
    private final List<CommitMessage> commitMessages;
}

/**
 * This file includes several ManifestEntry, representing the additional changes since last snapshot.
 */
public class ManifestFile extends ObjectsFile<ManifestEntry> {
    private final SchemaManager schemaManager;
    private final RowType partitionType;
    private final FormatWriterFactory writerFactory;
    private final long suggestedFileSize;
}

// 有 write 方法将各种 ManifestEntry 写进去 ManifestFile，其中会统计对应的 metadata

// This file includes several ManifestFileMeta, representing all data of the whole table at the corresponding snapshot.

public class ManifestList extends ObjectsFile<ManifestFileMeta> {
    public String write(List<ManifestFileMeta> metas) {
        return super.writeWithoutRolling(metas);
    }
}