uk.ac.starlink.table.storage

Class NioByteStoreAccess

java.lang.Object

uk.ac.starlink.table.storage.NioByteStoreAccess

All Implemented Interfaces:

ByteStoreAccess

public abstract class NioByteStoreAccess
extends Object
implements ByteStoreAccess

Partial implementation of ByteStoreAccess. Not thread-safe.

Since:

20 Aug 2010

Author:

Mark Taylor

Constructor Summary

Constructors

Constructor and Description
NioByteStoreAccess()

Method Summary

Modifier and Type	Method and Description
static ByteBuffer[]	copyBuffers(ByteBuffer[] bufs) Utility method to make a deep copy of an array of ByteBuffers.
static ByteStoreAccess	createAccess(ByteBuffer[] bbufs) Returns a reader implementation for an array of ByteBuffers.
protected abstract ByteBuffer	getBuffer(int nbyte) Returns a buffer with at least the requested number of bytes between the current position and the limit.
byte	readByte() Reads a byte from the current position.
void	readBytes(byte[] b, int offset, int length) Reads bytes into a buffer from the current position.
char	readChar() Reads a char from the current position.
double	readDouble() Reads a double from the current position.
float	readFloat() Reads a float from the current position.
int	readInt() Reads an int from the current position.
long	readLong() Reads a long from the current position.
short	readShort() Reads a short from the current position.

Methods inherited from class java.lang.Object

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

Methods inherited from interface uk.ac.starlink.table.storage.ByteStoreAccess

seek, skip

Constructor Detail

NioByteStoreAccess

public NioByteStoreAccess()

Method Detail

getBuffer

protected abstract ByteBuffer getBuffer(int nbyte)
                                 throws IOException

Returns a buffer with at least the requested number of bytes between the current position and the limit. When nbyte bytes have been read from the returned buffer, the current position of this ByteStoreAccess will have advanced by nbyte bytes. The position in the case that this call is made with no corresponding read is undefined, so it's important that the read is actually done (don't call this method speculatively).

If no such buffer is available (the end of the storage has been reached), then an IOException will be thrown.

Parameters:

nbyte - number of bytes required

Returns:

buffer from which nbyte bytes can be read

Throws:

IOException

readByte

public byte readByte()
              throws IOException

Description copied from interface: ByteStoreAccess

Reads a byte from the current position.

Specified by:

readByte in interface ByteStoreAccess

Returns:

read value

Throws:

IOException

readShort

public short readShort()
                throws IOException

Description copied from interface: ByteStoreAccess

Reads a short from the current position.

Specified by:

readShort in interface ByteStoreAccess

Returns:

read value

Throws:

IOException

readChar

public char readChar()
              throws IOException

Description copied from interface: ByteStoreAccess

Reads a char from the current position.

Specified by:

readChar in interface ByteStoreAccess

Returns:

read value

Throws:

IOException

readInt

public int readInt()
            throws IOException

Description copied from interface: ByteStoreAccess

Reads an int from the current position.

Specified by:

readInt in interface ByteStoreAccess

Returns:

read value

Throws:

IOException

readLong

public long readLong()
              throws IOException

Description copied from interface: ByteStoreAccess

Reads a long from the current position.

Specified by:

readLong in interface ByteStoreAccess

Returns:

read value

Throws:

IOException

readFloat

public float readFloat()
                throws IOException

Description copied from interface: ByteStoreAccess

Reads a float from the current position.

Specified by:

readFloat in interface ByteStoreAccess

Returns:

read value

Throws:

IOException

readDouble

public double readDouble()
                  throws IOException

Description copied from interface: ByteStoreAccess

Reads a double from the current position.

Specified by:

readDouble in interface ByteStoreAccess

Returns:

read value

Throws:

IOException

readBytes

public void readBytes(byte[] b,
                      int offset,
                      int length)
               throws IOException

Description copied from interface: ByteStoreAccess

Reads bytes into a buffer from the current position.

Specified by:

readBytes in interface ByteStoreAccess

Parameters:

b - buffer to receive bytes

offset - offset into b for first byte

length - number of bytes to read

Throws:

IOException

copyBuffers

public static ByteBuffer[] copyBuffers(ByteBuffer[] bufs)

Utility method to make a deep copy of an array of ByteBuffers.

Parameters:

bufs - input buffers

Returns:

matching array with buffers that are duplicates of the input elements

createAccess

public static ByteStoreAccess createAccess(ByteBuffer[] bbufs)

Returns a reader implementation for an array of ByteBuffers.

Parameters:

bbufs - buffer array

Returns:

reader implementation