Package org.apache.cassandra.io.util

Class WrappingRebufferer

java.lang.Object
org.apache.cassandra.io.util.WrappingRebufferer
All Implemented Interfaces:
AutoCloseable, ReaderFileProxy, Rebufferer, Rebufferer.BufferHolder
Direct Known Subclasses:
LimitingRebufferer, TailOverridingRebufferer
@NotThreadSafe public abstract class WrappingRebufferer extends Object implements Rebufferer, Rebufferer.BufferHolder
Instantiated once per RandomAccessReader, thread-unsafe. The instances reuse themselves as the BufferHolder to avoid having to return a new object for each rebuffer call. Only one buffer holder can be active at a time. Calling rebuffer(long) before the previously obtained buffer holder is released will throw AssertionError. We will get that exception also in case we try to close the rebufferer without closing the recently obtained buffer holder.

Calling methods of Rebufferer.BufferHolder will also produce AssertionError if buffer holder is not acquired.

The overriding classes must conform to the aforementioned rules.

  • Field Details

  • Constructor Details

    • WrappingRebufferer

      public WrappingRebufferer(Rebufferer wrapped)

  • Method Details

    • rebuffer

      public Rebufferer.BufferHolder rebuffer(long position)
      Description copied from interface: Rebufferer
      Rebuffer (move on or seek to) a given position, and return a buffer that can be used there. The only guarantee about the size of the returned data is that unless rebuffering at the end of the file, the buffer will not be empty and will contain the requested position, i.e. offset <= position < offset + bh.buffer().limit(), but the buffer will not be positioned there.
      Specified by:
      rebuffer in interface Rebufferer

    • channel

      public ChannelProxy channel()
      Specified by:
      channel in interface ReaderFileProxy

    • fileLength

      public long fileLength()
      Specified by:
      fileLength in interface ReaderFileProxy

    • getCrcCheckChance

      public double getCrcCheckChance()
      Description copied from interface: ReaderFileProxy
      Needed for tests. Returns the table's CRC check chance, which is only set for compressed tables.
      Specified by:
      getCrcCheckChance in interface ReaderFileProxy

    • close

      public void close()
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface ReaderFileProxy

    • closeReader

      public void closeReader()
      Description copied from interface: Rebufferer
      Called when a reader is closed. Should clean up reader-specific data.
      Specified by:
      closeReader in interface Rebufferer

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • buffer

      public ByteBuffer buffer()
      Description copied from interface: Rebufferer.BufferHolder
      Returns a useable buffer (i.e. one whose position and limit can be freely modified). Its limit will be set to the size of the available data in the buffer. The buffer must be treated as read-only.
      Specified by:
      buffer in interface Rebufferer.BufferHolder

    • offset

      public long offset()
      Description copied from interface: Rebufferer.BufferHolder
      Position in the file of the start of the buffer.
      Specified by:
      offset in interface Rebufferer.BufferHolder

    • release

      public void release()
      Description copied from interface: Rebufferer.BufferHolder
      To be called when this buffer is no longer in use. Must be called for all BufferHolders, or ChunkCache will not be able to free blocks.
      Specified by:
      release in interface Rebufferer.BufferHolder