# Bucket Versioning Design Guide [![Slack](https://slack.min.io/slack?type=svg)](https://slack.min.io) [![Docker Pulls](https://img.shields.io/docker/pulls/minio/minio.svg?maxAge=604800)](https://hub.docker.com/r/minio/minio/)

## Description of `xl.meta`

`xl.meta` is a new self describing backend format used by MinIO to support AWS S3 compatible versioning.
This file is the source of truth for each `version` at rest. `xl.meta` is a msgpack file serialized from a

    public String createdBy;

    /** The created time of the label type. */
    public String createdTime;

    /** The version number of the label type. */
    public String versionNo;

    /**
     * Clears the pager fields.
     */
    public void clear() {
        allRecordCount = 0;
        allPageCount = 0;
        existPrePage = false;
        existNextPage = false;

    public String createdBy;

    /** Creation time for search filtering. */
    public String createdTime;

    /** Version number for search filtering. */
    public String versionNo;

    /**
     * Default constructor for BadWordPager.
     */
    public BadWordPager() {
        // Default constructor
    }

    /**
     * Clears all search criteria and resets pagination settings.

import org.apache.maven.artifact.resolver.filter.ArtifactFilter;
import org.apache.maven.artifact.versioning.ArtifactVersion;
import org.apache.maven.artifact.versioning.DefaultArtifactVersion;
import org.apache.maven.artifact.versioning.OverConstrainedVersionException;
import org.apache.maven.artifact.versioning.VersionRange;

/**
 */
public class DefaultArtifact implements Artifact {
    private String groupId;

Note that objects with `null` versions, i.e. objects created prior to enabling versioning break the immutability guarantees provided by versioning. When existing object replication is enabled, these objects will be replicated as `null` versions to the remote targets provided they are not present on the target or if `null` version of object on source is newer than the `null` version of object on target.

  <groupId>ut.simple</groupId>
  <artifactId>artifact</artifactId>
  <versioning>
    <latest>1.0</latest>
    <release>1.0</release>
    <versions>
      <version>1.0</version>
    </versions>
    <lastUpdated>20111123122038</lastUpdated>
  </versioning>

       gives data about available versions (<<<latest>>>, <<<release>>>, <<<versions>>> list and <<<lastUpdated>>>),

 [[3]] in a "groupId/artifactId/version" snapshot artifact directory: metadata describes <<<groupId>>>, <<<artifactId>>>, <<<version>>> (base version, i.e. ending in <<<-SNAPSHOT>>>) and

                getLogger().debug(artifact.getArtifactId() + ": using locally installed snapshot");
            }
        }
        return version;
    }

    protected abstract String constructVersion(Versioning versioning, String baseVersion);

				if err != nil {
					writeErrorResponse(ctx, w, exportError(ctx, err, cfgFile, bucket), r.URL)
					return
				}
				// ignore empty versioning configs
				if config.Status != versioning.Enabled && config.Status != versioning.Suspended {
					continue
				}
				configData, err := xml.Marshal(config)
				if err != nil {
					writeErrorResponse(ctx, w, exportError(ctx, err, cfgFile, bucket), r.URL)

    /**
     * The timestamp when this request header was created.
     */
    public String createdTime;

    /**
     * The version number for optimistic locking.
     */
    public String versionNo;

    /**
     * Default constructor for ReqHeaderPager.
     * Initializes the pager with default values for page size and current page number.
     */
    public ReqHeaderPager() {