org.jlab.coda.jevio

Class EventParser

java.lang.Object

org.jlab.coda.jevio.EventParser

public class EventParser
extends java.lang.Object

Creates an object that controls the parsing of events. This object, like the EvioReader object, has a method for parsing an event. An EvioReader object will ultimately call this method--i.e., the concrete implementation of event parsing is in this class.

Author:

heddle, timmer

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	notificationActive This flag determines whether notification of listeners is active.

Constructor Summary

Constructors

Constructor and Description
EventParser()

Method Summary

Modifier and Type	Method and Description
void	addEvioListener(IEvioListener listener) Add an Evio listener.
(package private) static BankHeader	createBankHeader(byte[] bytes, int offset, java.nio.ByteOrder byteOrder) Create a bank header from the first eight bytes of the data array.
(package private) static SegmentHeader	createSegmentHeader(byte[] bytes, int offset, java.nio.ByteOrder byteOrder) Create a segment header from the first four bytes of the data array.
(package private) static TagSegmentHeader	createTagSegmentHeader(byte[] bytes, int offset, java.nio.ByteOrder byteOrder) Create a tag segment header from the first four bytes of the data array.
boolean	isNotificationActive() Get the flag determining whether notification of listeners is active.
protected void	notifyEvioListeners(EvioEvent evioEvent, IEvioStructure structure) This is when a structure is encountered while parsing an event.
protected void	notifyStart(EvioEvent evioEvent) Notify listeners we are starting to parse a new event
protected void	notifyStop(EvioEvent evioEvent) Notify listeners we are done to parsing a new event
void	parseEvent(EvioEvent evioEvent) This is the workhorse method for parsing the event.
void	removeEvioListener(IEvioListener listener) Remove an Evio listener.
void	setEvioFilter(IEvioFilter evioFilter) Set the global filter used for filtering structures.
void	setNotificationActive(boolean notificationActive) Set the flag determining whether notification of listeners is active.

Methods inherited from class java.lang.Object

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

Field Detail

notificationActive

protected boolean notificationActive

This flag determines whether notification of listeners is active. Normally it is. But in some cases it should be temporarily suspended. For example, in a "goto event" process, the listeners will not be notified of the intervening events as the file is scanned to get to the target event.

Constructor Detail

EventParser

public EventParser()

Method Detail

parseEvent

public void parseEvent(EvioEvent evioEvent)
                throws EvioException

This is the workhorse method for parsing the event. It will drill down and uncover all structures (banks, segments, and tagsegments) and notify any interested listeners in a SAX-Like manner.
Note: applications may choose not to provide a listener. In that case, when the event is parsed, its structures may be accessed through the event's tree model, i.e., via event.getTreeModel().

Parameters:

evioEvent - the event to parse.

Throws:

EvioException - if arg is null.

createBankHeader

static BankHeader createBankHeader(byte[] bytes,
                                   int offset,
                                   java.nio.ByteOrder byteOrder)
                            throws EvioException

Create a bank header from the first eight bytes of the data array.

Parameters:

bytes - the byte array, probably from a bank that encloses this new bank.

offset - the offset to start reading from the byte array.

byteOrder - byte order of array, ByteOrder.BIG_ENDIAN or ByteOrder.LITTLE_ENDIAN

Returns:

the new bank header.

Throws:

EvioException - if data not in evio format.

createSegmentHeader

static SegmentHeader createSegmentHeader(byte[] bytes,
                                         int offset,
                                         java.nio.ByteOrder byteOrder)
                                  throws EvioException

Create a segment header from the first four bytes of the data array.

Parameters:

bytes - the byte array, probably from a bank that encloses this new segment.

offset - the offset to start reading from the byte array.

byteOrder - byte order of array, ByteOrder.BIG_ENDIAN or ByteOrder.LITTLE_ENDIAN

Returns:

the new segment header.

Throws:

EvioException - if data not in evio format.

createTagSegmentHeader

static TagSegmentHeader createTagSegmentHeader(byte[] bytes,
                                               int offset,
                                               java.nio.ByteOrder byteOrder)
                                        throws EvioException

Create a tag segment header from the first four bytes of the data array.

Parameters:

bytes - the byte array, probably from a bank that encloses this new tag segment.

offset - the offset to start reading from the byte array.

byteOrder - byte order of array, ByteOrder.BIG_ENDIAN or ByteOrder.LITTLE_ENDIAN

Returns:

the new tagsegment header.

Throws:

EvioException - if data not in evio format.

notifyEvioListeners

protected void notifyEvioListeners(EvioEvent evioEvent,
                                   IEvioStructure structure)

This is when a structure is encountered while parsing an event. It notifies all listeners about the structure.

Parameters:

evioEvent - event being parsed

structure - the structure encountered, which may be a Bank, Segment, or TagSegment.

notifyStart

protected void notifyStart(EvioEvent evioEvent)

Notify listeners we are starting to parse a new event

Parameters:

evioEvent - the event in question;

notifyStop

protected void notifyStop(EvioEvent evioEvent)

Notify listeners we are done to parsing a new event

Parameters:

evioEvent - the event in question;

removeEvioListener

public void removeEvioListener(IEvioListener listener)

Remove an Evio listener. Evio listeners listen for structures encountered when an event is being parsed.

Parameters:

listener - The Evio listener to remove.

addEvioListener

public void addEvioListener(IEvioListener listener)

Add an Evio listener. Evio listeners listen for structures encountered when an event is being parsed.

Parameters:

listener - The Evio listener to add.

isNotificationActive

public boolean isNotificationActive()

Get the flag determining whether notification of listeners is active. Normally it is. But in some cases it should be temporarily suspended. For example, in a "goto event" process, the listeners will not be notified of the intervening events as the file is scanned to get to the target event.

Returns:

true if notification of events to the listeners is active.

setNotificationActive

public void setNotificationActive(boolean notificationActive)

Set the flag determining whether notification of listeners is active. Normally it is. But in some cases it should be temporarily suspended. For example, in a "goto event" process, the listeners will not be notified of the intervening events as the file is scanned to get to the target event.

Parameters:

notificationActive - set true if notification of events to the listeners is active.

setEvioFilter

public void setEvioFilter(IEvioFilter evioFilter)

Set the global filter used for filtering structures. If set to null, the default, then all structures will be sent to the listeners.

Parameters:

evioFilter - the filter to set.

See Also:

IEvioFilter