org.jlab.coda.jevio

Interface IBlockHeader

All Known Implementing Classes:

BlockHeaderV2, BlockHeaderV4

public interface IBlockHeader

Make a common interface for different versions of the BlockHeader.

Author:

timmer

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAGIC_NUMBER The magic number, should be the value of magicNumber.

Method Summary

Methods

Modifier and Type	Method and Description
int	bytesRemaining(long position) Gives the bytes remaining in this block (physical record) given a buffer position.
long	firstEventStartingPosition() Determines where the start of the first event (logical record) in this block (physical record) is located (in bytes).
long	getBufferEndingPosition() Get the position in the buffer (in bytes) of this block's last data word.
long	getBufferStartingPosition() Get the starting position in the buffer (in bytes) from which this header was read--if that happened. This is not part of the block header proper.
int	getHeaderLength() Get the block header length, in ints.
int	getMagicNumber() Get the magic number the block (physical record) header which should be 0xc0da0100.
int	getNumber() Get the block number for this block (physical record).
int	getSize() Get the size of the block (physical record).
int	getVersion() Get the evio version of the block (physical record) header.
boolean	hasDictionary() Is this block's first event is an evio dictionary?
boolean	isLastBlock() Is this the last block in the file or being sent over the network?
long	nextBufferStartingPosition() Determines where the start of the next block (physical record) header in some buffer is located (in bytes).
void	setBufferStartingPosition(long bufferStartingPosition) Set the starting position in the buffer (in bytes) from which this header was read--if that happened. This is not part of the block header proper.
java.lang.String	toString() Obtain a string representation of the block (physical record) header.
int	write(java.nio.ByteBuffer byteBuffer) Write myself out a byte buffer.

Field Detail

MAGIC_NUMBER

static final int MAGIC_NUMBER

The magic number, should be the value of magicNumber.

See Also:

Constant Field Values

Method Detail

getSize

int getSize()

Get the size of the block (physical record).

Returns:

the size of the block (physical record) in ints.

getNumber

int getNumber()

Get the block number for this block (physical record). In a file, this is usually sequential.

Returns:

the block number for this block (physical record).

getHeaderLength

int getHeaderLength()

Get the block header length, in ints. This should be 8.

Returns:

the block header length. This should be 8.

getVersion

int getVersion()

Get the evio version of the block (physical record) header.

Returns:

the evio version of the block (physical record) header.

getMagicNumber

int getMagicNumber()

Get the magic number the block (physical record) header which should be 0xc0da0100.

Returns:

the magic number in the block (physical record).

getBufferEndingPosition

long getBufferEndingPosition()

Get the position in the buffer (in bytes) of this block's last data word.

Returns:

the position in the buffer (in bytes) of this block's last data word.

getBufferStartingPosition

long getBufferStartingPosition()

Get the starting position in the buffer (in bytes) from which this header was read--if that happened.
This is not part of the block header proper. It is a position in a memory buffer of the start of the block (physical record). It is kept for convenience. It is up to the reader to set it.

Returns:

the starting position in the buffer (in bytes) from which this header was read--if that happened.

setBufferStartingPosition

void setBufferStartingPosition(long bufferStartingPosition)

Set the starting position in the buffer (in bytes) from which this header was read--if that happened.
This is not part of the block header proper. It is a position in a memory buffer of the start of the block (physical record). It is kept for convenience. It is up to the reader to set it.

Parameters:

bufferStartingPosition - the starting position in the buffer from which this header was read--if that happened.

nextBufferStartingPosition

long nextBufferStartingPosition()

Determines where the start of the next block (physical record) header in some buffer is located (in bytes). This assumes the start position has been maintained by the object performing the buffer read.

Returns:

the start of the next block (physical record) header in some buffer is located (in bytes).

firstEventStartingPosition

long firstEventStartingPosition()

Determines where the start of the first event (logical record) in this block (physical record) is located (in bytes). This assumes the start position has been maintained by the object performing the buffer read.

Returns:

where the start of the first event (logical record) in this block (physical record) is located (in bytes). Returns 0 if start is 0, signaling that this entire physical record is part of a logical record that spans at least three physical records.

bytesRemaining

int bytesRemaining(long position)
                   throws EvioException

Gives the bytes remaining in this block (physical record) given a buffer position. The position is an absolute position in a byte buffer. This assumes that the absolute position in bufferStartingPosition is being maintained properly by the reader. No block is longer than 2.1GB - 31 bits of length. This is for practical reasons - so a block can be read into a single byte array.

Parameters:

position - the absolute current position is a byte buffer.

Returns:

the number of bytes remaining in this block (physical record.)

Throws:

EvioException

hasDictionary

boolean hasDictionary()

Is this block's first event is an evio dictionary?

Returns:

true if this block's first event is an evio dictionary, else false

isLastBlock

boolean isLastBlock()

Is this the last block in the file or being sent over the network?

Returns:

true if this is the last block in the file or being sent over the network, else false

write

int write(java.nio.ByteBuffer byteBuffer)

Write myself out a byte buffer. This write is relative--i.e., it uses the current position of the buffer.

Parameters:

byteBuffer - the byteBuffer to write to.

Returns:

the number of bytes written, which for a BlockHeader is 32.

toString

java.lang.String toString()

Obtain a string representation of the block (physical record) header.

Overrides:

toString in class java.lang.Object

Returns:

a string representation of the block (physical record) header.