com.pervasive.datarush.io

Class SplittableCompressedFileSplit

java.lang.Object

com.pervasive.datarush.io.FileSplit

com.pervasive.datarush.io.SplittableCompressedFileSplit

All Implemented Interfaces:

DataSplit, Serializable

public class SplittableCompressedFileSplit
extends FileSplit

Represents a file split for a compression format that supports splitting. The CompressedFileSplit only works with formats that do not support splitting (i.e. one split is used that represents the whole file).

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
SplittableCompressedFileSplit(Path path, long startOffset, long length, CompressionFormat format) Construct an instance.

Method Summary

Modifier and Type	Method and Description
FileSplit	authorize(FileClient client) Creates an identical split which will use the specified authorization context for access.
CompressionFormat	getCompressionFormat() Get the compression format.
InputStream	openSource() Opens the underlying source for access.
SplitInputStream	openSplit(int buffer) Opens the split for reading using the specified size for the read buffer.

Methods inherited from class com.pervasive.datarush.io.FileSplit

getEndOffset, getFileClient, getLength, getPath, getStartOffset, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

SplittableCompressedFileSplit

public SplittableCompressedFileSplit(Path path,
                                     long startOffset,
                                     long length,
                                     CompressionFormat format)

Construct an instance.

Parameters:

path - path to the file to read

startOffset - starting offset of this split within the file

length - length (in bytes) of the split

format - compression format (must support splitting)

Method Detail

authorize

public FileSplit authorize(FileClient client)

Description copied from interface: DataSplit

Creates an identical split which will use the specified authorization context for access.

This method is used by clients of the IO APIs which want to provide an alternative to the OS-level authorization inherited from the JVM's execution environment. Data access methods for the split will use the supplied context.

The authorization context is not a serializable attribute of a data split, as it represents the environment in which the data in accesses, not a property of the data itself. The context is associated with the split as a matter of convenience.

Specified by:

authorize in interface DataSplit

Overrides:

authorize in class FileSplit

Parameters:

client - the authorization context to use for access

Returns:

a split using the provided authorization context

openSource

public InputStream openSource()
                       throws IOException

Description copied from interface: DataSplit

Opens the underlying source for access. Initially, the stream is positioned at the first byte of the source. Unlike DataSplit.openSplit(int), the caller is responsible for making sure accesses are aligned to split boundaries. The stream is also unbuffered.

This method may be required for dealing with formats which store metadata at the beginning of the file.

Specified by:

openSource in interface DataSplit

Overrides:

openSource in class FileSplit

Returns:

a reader of the data in the underlying source

Throws:

IOException - if an I/O error occurs opening the underlying source

openSplit

public SplitInputStream openSplit(int buffer)
                           throws IOException

Description copied from interface: DataSplit

Opens the split for reading using the specified size for the read buffer. The reader will initially be positioned at the first byte of the split. The reader will indicate when the last byte of the split has been read via SplitInputStreamImpl.hasOverrun().

Specified by:

openSplit in interface DataSplit

Overrides:

openSplit in class FileSplit

Parameters:

buffer - the size of the buffer to use for reads, in bytes

Returns:

a reader of the data in the split

Throws:

IOException - if an I/O error occurs opening the underlying source

getCompressionFormat

public CompressionFormat getCompressionFormat()

Get the compression format.

Returns:

compressionFormat