com.pervasive.datarush.io

Class CompressedFileSplit

java.lang.Object

com.pervasive.datarush.io.FileSplit

com.pervasive.datarush.io.CompressedFileSplit

All Implemented Interfaces:

DataSplit, Serializable

public class CompressedFileSplit
extends FileSplit

Describes a range of bytes from a compressed file. As most, if not all compression schemes cannot support starting decompression at an arbitrary point, only entire file splits are supported.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
CompressedFileSplit(Path path, CompressionFormat format) Creates a split encompassing the entire file named by the path.

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.
InputStream	openSource() Opens the underlying source for access.

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

getEndOffset, getFileClient, getLength, getPath, getStartOffset, openSplit, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

CompressedFileSplit

public CompressedFileSplit(Path path,
                           CompressionFormat format)

Creates a split encompassing the entire file named by the path.

Parameters:

path - the file on which the split is defined

format - the compression format of the file

Method Detail

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

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