de.lmu.ifi.dbs.elki.persistent

Class OnDiskUpperTriangleMatrix

java.lang.Object

de.lmu.ifi.dbs.elki.persistent.OnDiskUpperTriangleMatrix

All Implemented Interfaces:

java.lang.AutoCloseable

public class OnDiskUpperTriangleMatrix
extends java.lang.Object
implements java.lang.AutoCloseable

Class representing an upper triangle matrix backed by an on-disk array of O((n+1)*n/2) size

Since:

0.2

Author:

Erich Schubert

Field Summary

Fields

Modifier and Type	Field and Description
private OnDiskArray	array Data storage
private int	matrixsize Size of the matrix
private static long	serialVersionUID Serial number, also used for generating a magic
private static int	TRIANGLE_HEADER_SIZE Size of this class' header

Constructor Summary

Constructors

Constructor and Description
OnDiskUpperTriangleMatrix(java.io.File filename, int magicseed, int extraheadersize, int recordsize, boolean writable) Constructor to access an existing array.
OnDiskUpperTriangleMatrix(java.io.File filename, int magicseed, int extraheadersize, int recordsize, int matrixsize) Constructor to access a new array.

Method Summary

Modifier and Type	Method and Description
private static int	arraysize(int matrixsize) Compute the size of the needed backing array from the matrix dimensions.
void	close() Close the matrix file.
private int	computeOffset(int x, int y) Compute the offset within the file.
int	getMatrixSize() Query the size of the matrix.
java.nio.ByteBuffer	getRecordBuffer(int x, int y) Get a record buffer
void	resizeMatrix(int newsize) Resize the matrix to cover newsize x newsize.

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

Serial number, also used for generating a magic

See Also:

Constant Field Values

TRIANGLE_HEADER_SIZE

private static final int TRIANGLE_HEADER_SIZE

Size of this class' header

See Also:

Constant Field Values

matrixsize

private int matrixsize

Size of the matrix

array

private OnDiskArray array

Data storage

Constructor Detail

OnDiskUpperTriangleMatrix

public OnDiskUpperTriangleMatrix(java.io.File filename,
                                 int magicseed,
                                 int extraheadersize,
                                 int recordsize,
                                 boolean writable)
                          throws java.io.IOException

Constructor to access an existing array.

Parameters:

filename - File name

magicseed - Magic number

extraheadersize - Size of extra header data

recordsize - Record size

writable - flag to open writable

Throws:

java.io.IOException - on IO errors

OnDiskUpperTriangleMatrix

public OnDiskUpperTriangleMatrix(java.io.File filename,
                                 int magicseed,
                                 int extraheadersize,
                                 int recordsize,
                                 int matrixsize)
                          throws java.io.IOException

Constructor to access a new array.

Parameters:

filename - File name

magicseed - Magic number

extraheadersize - Size of extra header data

recordsize - Record size

matrixsize - Size of matrix to store

Throws:

java.io.IOException - on IO errors

Method Detail

resizeMatrix

public void resizeMatrix(int newsize)
                  throws java.io.IOException

Resize the matrix to cover newsize x newsize.

Parameters:

newsize - New matrix size.

Throws:

java.io.IOException - on IO errors

arraysize

private static int arraysize(int matrixsize)

Compute the size of the needed backing array from the matrix dimensions.

Parameters:

matrixsize - size of the matrix

Returns:

size of the array

computeOffset

private int computeOffset(int x,
                          int y)

Compute the offset within the file.

Parameters:

x - First coordinate

y - Second coordinate

Returns:

Linear offset

getRecordBuffer

public java.nio.ByteBuffer getRecordBuffer(int x,
                                           int y)
                                    throws java.io.IOException

Get a record buffer

Parameters:

x - First coordinate

y - Second coordinate

Returns:

Byte buffer for the record

Throws:

java.io.IOException - on IO errors

close

public void close()
           throws java.io.IOException

Close the matrix file.

Specified by:

close in interface java.lang.AutoCloseable

Throws:

java.io.IOException - on IO errors

getMatrixSize

public int getMatrixSize()

Query the size of the matrix.

Returns:

size of the matrix