Package org.apache.jackrabbit.oak.segment.spi.persistence

Interface SegmentArchiveReader

All Superinterfaces:
AutoCloseable, Closeable
All Known Implementing Classes:
AbstractRemoteSegmentArchiveReader, AwsSegmentArchiveReader, AzureSegmentArchiveReader, AzureSegmentArchiveReaderV8, CachingSegmentArchiveReader, SegmentTarReader
public interface SegmentArchiveReader extends Closeable
This interface represents a read-only segment archive. Since the underlying data structure is immutable, the implementation should be thread safe.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    close()
    Close the archive.
    boolean
    containsSegment(long msb, long lsb)
    Check if the segment exists.
    @NotNull Buffer
    getBinaryReferences()
    Load binary references.
    int
    getEntrySize(int size)
    Transforms the segment size in bytes into the effective size on disk for the given entry (eg.
    @Nullable Buffer
    getGraph()
    Load the segment graph.
    @NotNull String
    getName()
    Get the name of the archive.
    boolean
    hasGraph()
    Check if the segment graph has been persisted for this archive.
    boolean
    isRemote()
    This method returns true if the storage is accessed via a network protocol, not tight to the traditional storage technology, for example, HTTP.
    long
    length()
    Get the current length of the archive.
    List<SegmentArchiveEntry>
    listSegments()
    List all the segments, in the order as they have been written to the archive.
    @Nullable Buffer
    readSegment(long msb, long lsb)
    Read the segment.

  • Method Details

    • readSegment

      @Nullable @Nullable Buffer readSegment(long msb, long lsb) throws IOException
      Read the segment.
      Parameters:
      msb - the most significant bits of the identifier of the segment
      lsb - the least significant bits of the identifier of the segment
      Returns:
      byte buffer containing the segment data or null if the segment doesn't exist
      Throws:
      IOException

    • containsSegment

      boolean containsSegment(long msb, long lsb)
      Check if the segment exists.
      Parameters:
      msb - the most significant bits of the identifier of the segment
      lsb - the least significant bits of the identifier of the segment
      Returns:
      true if the segment exists

    • listSegments

      List<SegmentArchiveEntry> listSegments()
      List all the segments, in the order as they have been written to the archive.
      Returns:
      segment list, ordered by their position in the archive

    • getGraph

      @Nullable @Nullable Buffer getGraph() throws IOException
      Load the segment graph.
      Returns:
      byte buffer representing the graph or null if the graph hasn't been persisted.
      Throws:
      IOException

    • hasGraph

      boolean hasGraph()
      Check if the segment graph has been persisted for this archive.
      Returns:
      true if the graph exists, false otherwise

    • getBinaryReferences

      @NotNull @NotNull Buffer getBinaryReferences() throws IOException
      Load binary references.
      Returns:
      byte buffer representing the binary references structure.
      Throws:
      IOException

    • length

      long length()
      Get the current length of the archive.
      Returns:
      length of the archive, in bytes

    • getName

      @NotNull @NotNull String getName()
      Get the name of the archive.
      Returns:
      archive name

    • close

      void close() throws IOException
      Close the archive.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Throws:
      IOException

    • getEntrySize

      int getEntrySize(int size)
      Transforms the segment size in bytes into the effective size on disk for the given entry (eg. by adding the number of padding bytes, header, etc.)
      Parameters:
      size - the segment size in bytes
      Returns:
      the number of bytes effectively used on the storage to save the segment

    • isRemote

      boolean isRemote()
      This method returns true if the storage is accessed via a network protocol, not tight to the traditional storage technology, for example, HTTP. Based on that info, for instance, calling classes can decide to update archive metadata (graph, binary references, index) more frequently, and not only when the archive is being closed. With that multiple Oak processes can access the storage simultaneously, with one process in read-write mode and one or more processes in read-only mode.
      Returns: