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

Interface PersistentCache

All Known Implementing Classes:
AbstractPersistentCache, PersistentDiskCache, PersistentRedisCache
public interface PersistentCache
This interface represents a cache which survives segment store restarts. The cache is agnostic to any archive structure. Segments are only identified by their UUIDs, specified as msb and lsb parts of the segment id.

  • Method Summary

    Modifier and Type
    Method
    Description
    void
    cleanUp()
    Purges the cache entries according to the implementation policy (e.g.
    boolean
    containsSegment(long msb, long lsb)
    Check if the segment exists in the cache.
    @Nullable Buffer
    readSegment(long msb, long lsb, @NotNull Callable<Buffer> loader)
    Reads the segment from cache.
    void
    writeSegment(long msb, long lsb, Buffer buffer)
    Writes the segment to the cache.

  • Method Details

    • readSegment

      @Nullable @Nullable Buffer readSegment(long msb, long lsb, @NotNull @NotNull Callable<Buffer> loader)
      Reads the segment from cache.
      Parameters:
      msb - the most significant bits of the identifier of the segment
      lsb - the least significant bits of the identifier of the segment
      loader - in case of cache miss, with loader.call() missing element will be retrieved
      Returns:
      byte buffer containing the segment data or null if the segment doesn't exist

    • containsSegment

      boolean containsSegment(long msb, long lsb)
      Check if the segment exists in the cache.
      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

    • writeSegment

      void writeSegment(long msb, long lsb, Buffer buffer)
      Writes the segment to the cache.
      Parameters:
      msb - the most significant bits of the identifier of the segment
      lsb - the least significant bits of the identifier of the segment
      buffer - the byte buffer containing the segment data

    • cleanUp

      void cleanUp()
      Purges the cache entries according to the implementation policy (e.g. maximum cache size, maximum number of entries, etc.)