org.jlab.coda.et
Class Event

java.lang.Object
  org.jlab.coda.et.Event

public class Event

extends java.lang.Object

This class defines an ET event.

Field Summary

(package private) int	age Specifies whether the event was obtained as a new event (through newEvents), or as a "used" event (through getEvents).
(package private) int	byteOrder An integer used to keep track of the data's byte ordering.
(package private) int[]	control An array of integers normally used by stations to filter events out of their input lists.
(package private) byte[]	data The event data is stored here.
(package private) int	dataStatus Status of the data.
(package private) int	id Unique id number.
(package private) boolean	isJava Flag specifying whether the ET system process is Java based or not.
(package private) int	length Length of the valid data in bytes.
(package private) int	memSize Size of the data buffer in bytes.
(package private) int	modify Specifies whether the user wants to read the event only, will modify only the event header, or will modify the data.
(package private) int	owner The attachment id which owns or got the event.
(package private) int	priority Event priority which is either high Constants.high or low Constants.low.
(package private) int	sizeLimit Size limit of events' data buffers in bytes.

Constructor Summary

(package private)	Event(int size) Creates an event object for users of Java-based ET systems or by the system itself.
(package private)	Event(int size, int limit, boolean isJavaSystem) Creates an event object for ET system users.

Method Summary

static int	bytesToInt(byte[] b, int off) Converts 4 bytes of a byte array into an integer.
static short	bytesToShort(byte[] b, int off) Converts 2 bytes of a byte array into a short.
void	codaSwap() Swaps data that is in the CODA format only.
byte[]	copyData() Gets the event's data array.
void	copyDataIn(byte[] dat) Set the event's data by copying it in.
void	copyDataIn(byte[] dat, int srcOff, int destOff, int len) Set the event's data by copying it in.
int	getByteOrder() Gets the event's byte order - either Constants.endianBig or Constants.endianLittle.
int[]	getControl() Gets the event's control array.
byte[]	getData() Gets the event's data array.
int	getDataStatus() Gets the status of the data.
int	getId() Gets the event's id number.
int	getLength() Gets the length of the data in bytes.
int	getMemSize() Gets the size of the data buffer in bytes.
int	getModify() Gets the event's modify value.
int	getPriority() Gets the event's priority.
int	getSizeLimit() Gets the size limit of the data buffer in bytes when using a C-based ET system.
(package private) void	init() Initialize an event's fields.
static void	intToBytes(int intVal, byte[] b, int off) Copies an integer value into 4 bytes of a byte array.
boolean	needToSwap() Tells caller if the event data needs to be swapped in order to be the correct byte order.
void	setByteOrder(int endian) Set the event's byte order.
void	setControl(int[] con) Sets the event's control array by copying it in.
void	setData(byte[] dat) Sets the event's data without copying.
void	setDataStatus(int status) Sets the event's data status.
void	setLength(int len) Sets the event's data length in bytes.
void	setPriority(int pri) Sets the event's priority.
static void	shortToBytes(short shortVal, byte[] b, int off) Copies a short value into 2 bytes of a byte array.
static void	swapArrayInt(byte[] b, int off) Swaps 4 bytes of a byte array in place.
static void	swapArrayShort(byte[] b, int off) Swaps 2 bytes of a byte array in place.
static int	swapInt(int n) Swaps the byte order of an integer.
static short	swapShort(short n) Swaps the byte order of a short.

Methods inherited from class java.lang.Object

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

Field Detail

id

int id

Unique id number.

age

int age

Specifies whether the event was obtained as a new event (through newEvents), or as a "used" event (through getEvents). If the event is new, its value is Constants.eventNew otherwise Constants.eventUsed.

priority

int priority

Event priority which is either high Constants.high or low Constants.low.

owner

int owner

The attachment id which owns or got the event. If it's owned by the system its value is Constants.system.

length

int length

Length of the valid data in bytes.

memSize

int memSize

Size of the data buffer in bytes.

sizeLimit

int sizeLimit

Size limit of events' data buffers in bytes. This is important to know when Java users connect to C-based ET systems. The C-based ET systems cannot allow users to increase an event's data size beyond what was originally allocated. In Java systems there is no size limit besides computer and JVM limits.

dataStatus

int dataStatus

Status of the data. It can be ok Constants.dataOk, corrupted Constants.dataCorrupt, or possibly corrupted Constants.dataPossiblyCorrupt.

byteOrder

int byteOrder

An integer used to keep track of the data's byte ordering.

modify

int modify

Specifies whether the user wants to read the event only, will modify only the event header, or will modify the data.

control

int[] control

An array of integers normally used by stations to filter events out of their input lists. It is used to control the flow of events through the ET system.

data

byte[] data

The event data is stored here.

isJava

boolean isJava

Flag specifying whether the ET system process is Java based or not.

Constructor Detail

Event

Event(int size)

Creates an event object for users of Java-based ET systems or by the system itself. Event objects are only created once in the ET system process - when the ET system is started up.

Parameters:

size - size of the data array in bytes

Event

Event(int size,
      int limit,
      boolean isJavaSystem)

Creates an event object for ET system users.

Parameters:

size - size of the data array in bytes.

limit - limit on the size of the data array in bytes. Only used for C-based ET systems.

isJavaSystem - is ET system Java based?

Method Detail

init

void init()

Initialize an event's fields. Called for an event each time it passes through GRAND_CENTRAL station.

getId

public int getId()

Gets the event's id number.

Returns:

event's id number

getPriority

public int getPriority()

Gets the event's priority.

Returns:

event's priority

getLength

public int getLength()

Gets the length of the data in bytes.

Returns:

length of the data in bytes

getMemSize

public int getMemSize()

Gets the size of the data buffer in bytes.

Returns:

size of the data buffer in bytes

getSizeLimit

public int getSizeLimit()

Gets the size limit of the data buffer in bytes when using a C-based ET system.

Returns:

size size limit of the data buffer in bytes

getDataStatus

public int getDataStatus()

Gets the status of the data.

Returns:

status of the data

getModify

public int getModify()

Gets the event's modify value.

Returns:

event's modify value

getControl

public int[] getControl()

Gets the event's control array.

Returns:

event's control array

getData

public byte[] getData()

Gets the event's data array.

Returns:

event's data array

copyData

public byte[] copyData()

Gets the event's data array.

Returns:

a clone of the event's data array

setData

public void setData(byte[] dat)
             throws EtException

Sets the event's data without copying. The length and memSize members of the event are automatically set to the data array's length.

Parameters:

dat - data array

Throws:

EtException

copyDataIn

public void copyDataIn(byte[] dat)
                throws EtException

Set the event's data by copying it in. The event's length member is set to the length of the argument array.

Parameters:

dat - data array

Throws:

EtException - if the data array is the wrong size

copyDataIn

public void copyDataIn(byte[] dat,
                       int srcOff,
                       int destOff,
                       int len)
                throws EtException

Set the event's data by copying it in. The event's length member is not changed.

Parameters:

dat - data array

srcOff - offset in "dat" byte array

destOff - offset in the event's byte array

len - bytes of data to copy

Throws:

EtException - if the data array is the wrong size

setPriority

public void setPriority(int pri)
                 throws EtException

Sets the event's priority.

Parameters:

pri - event priority

Throws:

EtException - if argument is a bad value

setLength

public void setLength(int len)
               throws EtException

Sets the event's data length in bytes.

Parameters:

len - data length

Throws:

EtException - if length is less than zero

setControl

public void setControl(int[] con)
                throws EtException

Sets the event's control array by copying it in.

Parameters:

con - control array

Throws:

EtException - if control array has the wrong number of elements

setDataStatus

public void setDataStatus(int status)
                   throws EtException

Sets the event's data status.

Parameters:

status - data status

Throws:

EtException - if argument is a bad value

getByteOrder

public int getByteOrder()

Gets the event's byte order - either Constants.endianBig or Constants.endianLittle.

Returns:

event's byte order

setByteOrder

public void setByteOrder(int endian)
                  throws EtException

Set the event's byte order. Values can be Constants.endianBig, Constants.endianLittle, Constants.endianLocal, Constants.endianNotLocal, or Constants.endianSwitch

Parameters:

endian - endian value

Throws:

EtException - if argument is a bad value

needToSwap

public boolean needToSwap()
                   throws EtException

Tells caller if the event data needs to be swapped in order to be the correct byte order.

Returns:

true if swapping is needed, otherwise false

Throws:

EtException - if the byte order has a bad value

codaSwap

public void codaSwap()

Swaps data that is in the CODA format only.

swapInt

public static final int swapInt(int n)

Swaps the byte order of an integer.

Parameters:

n - integer to be swapped

Returns:

swapped integer

swapShort

public static final short swapShort(short n)

Swaps the byte order of a short.

Parameters:

n - short to be swapped

Returns:

swapped short

bytesToInt

public static final int bytesToInt(byte[] b,
                                   int off)

Converts 4 bytes of a byte array into an integer.

Parameters:

b - byte array

off - offset into the byte array (0 = start at first element)

Returns:

integer value

intToBytes

public static final void intToBytes(int intVal,
                                    byte[] b,
                                    int off)

Copies an integer value into 4 bytes of a byte array.

Parameters:

intVal - integer value

b - byte array

off - offset into the byte array

swapArrayInt

public static final void swapArrayInt(byte[] b,
                                      int off)

Swaps 4 bytes of a byte array in place.

Parameters:

b - byte array

off - offset into the byte array

bytesToShort

public static final short bytesToShort(byte[] b,
                                       int off)

Converts 2 bytes of a byte array into a short.

Parameters:

b - byte array

off - offset into the byte array (0 = start at first element)

Returns:

short value

shortToBytes

public static final void shortToBytes(short shortVal,
                                      byte[] b,
                                      int off)

Copies a short value into 2 bytes of a byte array.

Parameters:

shortVal - short value

b - byte array

off - offset into the byte array

swapArrayShort

public static final void swapArrayShort(byte[] b,
                                        int off)

Swaps 2 bytes of a byte array in place.

Parameters:

b - byte array

off - offset into the byte array