org.apache.druid.segment.writeout

Interface SegmentWriteOutMedium

All Superinterfaces:

AutoCloseable, Closeable

All Known Implementing Classes:

OffHeapMemorySegmentWriteOutMedium, OnHeapMemorySegmentWriteOutMedium, TmpFileSegmentWriteOutMedium

public interface SegmentWriteOutMedium
extends Closeable

SegmentWriteOutMedium is an umbrella "resource disposer" for temporary buffers (in the form of WriteOutBytes, obtained by calling makeWriteOutBytes() on the SegmentWriteOutMedium instance), that are used during new Druid segment creation, and other resources (see getCloser()). When SegmentWriteOutMedium is closed, all child WriteOutBytes couldn't be used anymore.

Method Summary

Modifier and Type	Method and Description
Closer	getCloser() Returns a closer of this SegmentWriteOutMedium, which is closed in this SegmentWriteOutMedium's close() method.
SegmentWriteOutMedium	makeChildWriteOutMedium() Creates a 'child' version of the SegmentWriteOutMedium, which can be optionally closed, independent of this SegmentWriteOutMedium but otherwise shares the same configuration.
WriteOutBytes	makeWriteOutBytes() Creates a new empty WriteOutBytes, attached to this SegmentWriteOutMedium.

Methods inherited from interface java.io.Closeable

close

Method Detail

makeWriteOutBytes

WriteOutBytes makeWriteOutBytes()
                         throws IOException

Creates a new empty WriteOutBytes, attached to this SegmentWriteOutMedium. When this SegmentWriteOutMedium is closed, the returned WriteOutBytes couldn't be used anymore.

Throws:

IOException

makeChildWriteOutMedium

SegmentWriteOutMedium makeChildWriteOutMedium()
                                       throws IOException

Creates a 'child' version of the SegmentWriteOutMedium, which can be optionally closed, independent of this SegmentWriteOutMedium but otherwise shares the same configuration. This allows callers using a shared SegmentWriteOutMedium but which control the complete lifecycle of the WriteOutBytes which they require to free the backing resources when they are finished, rather than waiting until Closeable.close() is called for this medium. The 'child' medium will be closed when Closeable.close() is called, if not called explicitly prior to closing this medium.

Throws:

IOException

getCloser

Closer getCloser()

Returns a closer of this SegmentWriteOutMedium, which is closed in this SegmentWriteOutMedium's close() method. Could be used to "attach" some random resources to this SegmentWriteOutMedium, to be closed at the same time.