Interface ReadableTransaction

All Known Subinterfaces:
WriteableTransaction

public interface ReadableTransaction
Represents a readable transaction on a storage engine.
  • Method Details

    • read

      default ByteString read(TreeName treeName, ByteString key)
      Reads the record's value associated to the provided key, in the tree whose name is provided.
      Parameters:
      treeName - the tree name
      key - the record's key
      Returns:
      the record's value, or null if none exists or if the tree does not exist.
    • openCursor

      default Cursor<ByteString,ByteString> openCursor(TreeName treeName, ReadableTransaction.ReadOption... options)
      Opens a non-positioned cursor on the tree whose name is provided. The cursor will then have to be positioned (e.g: by invoking SequentialCursor.next()) to be defined.
      Parameters:
      treeName - the tree name
      options - the options to apply to the opened cursor.
      Returns:
      a new non-positioned cursor or an empty cursor if the tree does not exist.
    • getRecordCount

      default long getRecordCount(TreeName treeName)
      Returns the number of key/value pairs in the provided tree.
      Parameters:
      treeName - the tree name
      Returns:
      the number of key/value pairs in the provided tree or 0 if the tree does not exist.