com.pervasive.datarush.io

Class FileSplit

java.lang.Object

com.pervasive.datarush.io.FileSplit

All Implemented Interfaces:

DataSplit, Serializable

Direct Known Subclasses:

CompressedFileSplit, SplittableCompressedFileSplit

public class FileSplit
extends Object
implements DataSplit

Describes a range of bytes from a file. Ranges are identified by a start offset and a length. DataSplit objects are used to describe how files can be divided into pieces which can then be parsed in parallel.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
FileSplit(Path path) Creates a split encompassing the entire file named by the path.
FileSplit(Path path, long start, long length) Creates a split of the file named by the path.
FileSplit(String path) Creates a split encompassing the entire file named by the path.
FileSplit(String path, long start, long length) Creates a split of the 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.
long	getEndOffset() Gets the end index of the byte range represented by this split.
FileClient	getFileClient() Return the file client associated with this split.
long	getLength() Gets the length of the split, in bytes.
Path	getPath() Gets the path to the file on which the split is defined.
long	getStartOffset() Gets the byte offset of the beginning of the split.
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.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

FileSplit

public FileSplit(String path)

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

Parameters:

path - the file on which the split is defined

FileSplit

public FileSplit(String path,
                 long start,
                 long length)

Creates a split of the file named by the path.

Parameters:

path - the file on which the split is defined

start - the byte offset in the named file at which the split begins

length - the length of the split, in bytes

FileSplit

public FileSplit(Path path)

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

Parameters:

path - the file on which the split is defined

FileSplit

public FileSplit(Path path,
                 long start,
                 long length)

Creates a split of the file named by the path.

Parameters:

path - the file on which the split is defined

start - the byte offset in the named file at which the split begins

length - the length of the split, in bytes

Method Detail

getPath

public Path getPath()

Description copied from interface: DataSplit

Gets the path to the file on which the split is defined.

Some splits may not represent a file; in this case, null is returned.

Specified by:

getPath in interface DataSplit

Returns:

the path to the underlying source file.

getStartOffset

public long getStartOffset()

Description copied from interface: DataSplit

Gets the byte offset of the beginning of the split.

Specified by:

getStartOffset in interface DataSplit

Returns:

the position of the first byte of the split

getLength

public long getLength()

Description copied from interface: DataSplit

Gets the length of the split, in bytes.

Specified by:

getLength in interface DataSplit

Returns:

the size of the split

getEndOffset

public long getEndOffset()

Gets the end index of the byte range represented by this split. This offset is exclusive; that is, this represents the offset of the first byte past the end of the split.

Returns:

position of the end of the split

getFileClient

public FileClient getFileClient()

Return the file client associated with this split. May return null depending on the state.

Specified by:

getFileClient in interface DataSplit

Returns:

FileClient associated with this split.

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

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

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

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

Parameters:

client - the authorization context to use for access

Returns:

a split using the provided authorization context

toString

public String toString()

Overrides:

toString in class Object