org.jlab.coda.jevio

Interface IEvioReader

All Known Implementing Classes:

EvioReader, EvioReaderUnsyncV4, EvioReaderUnsyncV6, EvioReaderV4, EvioReaderV6

public interface IEvioReader

This interface is used to abstract various file and buffer reading functions. There are different readers for various evio versions and which are synchronized or unsynchronized. Created by timmer on 10/23/18.

Method Summary

Modifier and Type	Method and Description
boolean	checkBlockNumberSequence() Is this reader checking the block number sequence and throwing an exception if it's not sequential and starting with 1?
void	close() This is closes the file, but for buffers it only sets the position to 0.
long	fileSize() Get the size of the file being read, in bytes.
int	getBlockCount() This is the number of records in the file/buffer including the empty record or trailer at the end.
java.nio.ByteBuffer	getByteBuffer() Get the byte buffer being read directly or corresponding to the event file.
java.nio.ByteOrder	getByteOrder() Get the byte order of the file/buffer being read.
IBlockHeader	getCurrentBlockHeader() This returns the current (active) block (physical record) header.
java.lang.String	getDictionaryXML() Get the XML format dictionary if there is one.
EvioEvent	getEvent(int index) Get the event in the file/buffer at a given index (starting at 1).
byte[]	getEventArray(int eventNumber) Get an evio bank or event in byte array form.
java.nio.ByteBuffer	getEventBuffer(int eventNumber) Get an evio bank or event in ByteBuffer form.
int	getEventCount() This is the number of events in the file/buffer.
int	getEvioVersion() Get the evio version number.
IBlockHeader	getFirstBlockHeader() This returns the FIRST block (physical record) header.
EvioEvent	getFirstEvent() Get the "first" event if there is one.
int	getNumEventsRemaining() Get the number of events remaining in the file.
EventParser	getParser() Get the file/buffer parser.
java.lang.String	getPath() Get the path to the file.
EvioEvent	gotoEventNumber(int evNumber) Go to a specific event in the file.
boolean	hasDictionaryXML() Does this evio file have an associated XML dictionary?
boolean	hasFirstEvent() Does this evio file have an associated first event? It's also called the Beginning-Of-Run event.
boolean	isClosed() Has close() been called (without reopening by calling setBuffer(ByteBuffer))?
EvioEvent	nextEvent() Get the next event in the file/buffer.
void	parseEvent(EvioEvent evioEvent) This will parse an event, SAX-like.
EvioEvent	parseEvent(int index) This is a workhorse method.
EvioEvent	parseNextEvent() This is a workhorse method.
long	position() This is equivalent to obtaining the current position in the file.
void	rewind() The equivalent of rewinding the file.
void	setBuffer(java.nio.ByteBuffer buf) This method can be used to avoid creating additional EvioReader objects by reusing this one with another buffer.
void	setParser(EventParser parser) Set the file/buffer parser.
WriteStatus	toXMLFile(java.lang.String path) Rewrite the file to XML (not including dictionary and "first" event).
WriteStatus	toXMLFile(java.lang.String path, boolean hex) Rewrite the file to XML (not including dictionary and "first" event).
WriteStatus	toXMLFile(java.lang.String path, IEvioProgressListener progressListener) Rewrite the file to XML (not including dictionary and "first" event).
WriteStatus	toXMLFile(java.lang.String path, IEvioProgressListener progressListener, boolean hex) Rewrite the file to XML (not including dictionary and "first" event).

Method Detail

setBuffer

void setBuffer(java.nio.ByteBuffer buf)
        throws EvioException,
               java.io.IOException

This method can be used to avoid creating additional EvioReader objects by reusing this one with another buffer. The method close() is called before anything else.

Parameters:

buf - ByteBuffer to be read

Throws:

java.io.IOException - if read failure

EvioException - if buf is null; if first block number != 1 when checkBlkNumSeq arg is true

isClosed

boolean isClosed()

Has close() been called (without reopening by calling setBuffer(ByteBuffer))?

Returns:

true if this object closed, else false.

checkBlockNumberSequence

boolean checkBlockNumberSequence()

Is this reader checking the block number sequence and throwing an exception if it's not sequential and starting with 1?

Returns:

true if checking block number sequence, else false

getByteOrder

java.nio.ByteOrder getByteOrder()

Get the byte order of the file/buffer being read.

Returns:

byte order of the file/buffer being read.

getEvioVersion

int getEvioVersion()

Get the evio version number.

Returns:

evio version number.

getPath

java.lang.String getPath()

Get the path to the file.

Returns:

path to the file

getParser

EventParser getParser()

Get the file/buffer parser.

Returns:

file/buffer parser.

setParser

void setParser(EventParser parser)

Set the file/buffer parser.

Parameters:

parser - file/buffer parser.

getDictionaryXML

java.lang.String getDictionaryXML()

Get the XML format dictionary if there is one.

Returns:

XML format dictionary, else null.

hasDictionaryXML

boolean hasDictionaryXML()

Does this evio file have an associated XML dictionary?

Returns:

true if this evio file has an associated XML dictionary, else false

getFirstEvent

EvioEvent getFirstEvent()

Get the "first" event if there is one. It's also called the Beginning-Of-Run event. This event is defined once but included in each of the related split files written out.

Returns:

the first event if it existed, else null.

hasFirstEvent

boolean hasFirstEvent()

Does this evio file have an associated first event? It's also called the Beginning-Of-Run event. This event is defined once but included in each of the related split files written out.

Returns:

true if this evio file has an associated first event, else false

getNumEventsRemaining

int getNumEventsRemaining()
                   throws java.io.IOException,
                          EvioException

Get the number of events remaining in the file. Useful only if doing a sequential read.

Returns:

number of events remaining in the file

Throws:

java.io.IOException - if failed file access

EvioException - if failed reading from coda v3 file

getByteBuffer

java.nio.ByteBuffer getByteBuffer()

Get the byte buffer being read directly or corresponding to the event file. Not a very useful method. For files, it works only for evio format versions 2,3 and returns the internal buffer containing an evio block if using sequential access (for example files > 2.1 GB). It returns the memory mapped buffer otherwise. For reading buffers it returns the buffer being read.

Returns:

the byte buffer being read (in certain cases).

fileSize

long fileSize()

Get the size of the file being read, in bytes. For small files, obtain the file size using the memory mapped buffer's capacity.

Returns:

the file size in bytes

getFirstBlockHeader

IBlockHeader getFirstBlockHeader()

This returns the FIRST block (physical record) header.

Returns:

the first block header.

getEvent

EvioEvent getEvent(int index)
            throws java.io.IOException,
                   EvioException

Get the event in the file/buffer at a given index (starting at 1). As useful as this sounds, most applications will probably call parseNextEvent() or parseEvent(int) instead, since it combines combines getting an event with parsing it.

Parameters:

index - number of event desired, starting at 1, from beginning of file/buffer

Returns:

the event in the file/buffer at the given index or null if none

Throws:

java.io.IOException - if failed file access

EvioException - if failed read due to bad file/buffer format; if out of memory; if index out of bounds; if object closed

parseEvent

EvioEvent parseEvent(int index)
              throws java.io.IOException,
                     EvioException

This is a workhorse method. It retrieves the desired event from the file/buffer, and then parses it SAX-like. It will drill down and uncover all structures (banks, segments, and tagsegments) and notify any interested listeners.

Parameters:

index - number of event desired, starting at 1, from beginning of file/buffer

Returns:

the parsed event at the given index or null if none

Throws:

java.io.IOException - if failed file access

EvioException - if failed read due to bad file/buffer format; if out of memory; if index out of bounds; if object closed

nextEvent

EvioEvent nextEvent()
             throws java.io.IOException,
                    EvioException

Get the next event in the file/buffer. As useful as this sounds, most applications will probably call parseNextEvent() instead, since it combines getting the next event with parsing the next event.

Although this method can get events in versions 4+, it now delegates that to another method. No changes were made to this method from versions 1-3 in order to read the version 4 format as it is subset of versions 1-3 with variable block length.

Returns:

the next event in the file. On error it throws an EvioException. On end of file, it returns null.

Throws:

java.io.IOException - if failed file access

EvioException - if failed read due to bad buffer format; if object closed

parseNextEvent

EvioEvent parseNextEvent()
                  throws java.io.IOException,
                         EvioException

This is a workhorse method. It retrieves the next event from the file/buffer, and then parses it SAX-like. It will drill down and uncover all structures (banks, segments, and tagsegments) and notify any interested listeners.

Returns:

the event that was parsed. On error it throws an EvioException. On end of file, it returns null.

Throws:

java.io.IOException - if failed file access

EvioException - if read failure or bad format if object closed

parseEvent

void parseEvent(EvioEvent evioEvent)
         throws EvioException

This will parse an event, SAX-like. It will drill down and uncover all structures (banks, segments, and tagsegments) and notify any interested listeners.

As useful as this sounds, most applications will probably call parseNextEvent() instead, since it combines combines getting the next event with parsing the next event.

This method is only called by synchronized methods and therefore is not synchronized.

Parameters:

evioEvent - the event to parse.

Throws:

EvioException - if bad format

getEventArray

byte[] getEventArray(int eventNumber)
              throws EvioException,
                     java.io.IOException

Get an evio bank or event in byte array form.

Parameters:

eventNumber - number of event of interest (starting at 1).

Returns:

array containing bank's/event's bytes.

Throws:

java.io.IOException - if failed file access

EvioException - if eventNumber out of bounds (starts at 1); if the event number does not correspond to an existing event; if object closed

getEventBuffer

java.nio.ByteBuffer getEventBuffer(int eventNumber)
                            throws EvioException,
                                   java.io.IOException

Get an evio bank or event in ByteBuffer form.

Parameters:

eventNumber - number of event of interest

Returns:

buffer containing bank's/event's bytes.

Throws:

java.io.IOException - if failed file access

EvioException - if eventNumber is out of bounds; if the event number does not correspond to an existing event; if object closed

rewind

void rewind()
     throws java.io.IOException,
            EvioException

The equivalent of rewinding the file. What it actually does is set the position of the file/buffer back to where it was after calling the constructor - after the first header. This method, along with the two position() and the close() method, allows applications to treat files in a normal random access manner.

Throws:

java.io.IOException - if failed file access or buffer/file read

EvioException - if object closed

position

long position()
       throws java.io.IOException,
              EvioException

This is equivalent to obtaining the current position in the file. What it actually does is return the position of the buffer. This method, along with the rewind(), position(int) and the close() method, allows applications to treat files in a normal random access manner. Only meaningful to evio versions 1-3 and for sequential reading.

Returns:

the position of the buffer; -1 if version 4+

Throws:

java.io.IOException - if error accessing file

EvioException - if object closed

close

void close()
    throws java.io.IOException

This is closes the file, but for buffers it only sets the position to 0. This method, along with the rewind() and the two position() methods, allows applications to treat files in a normal random access manner.

Throws:

java.io.IOException - if error accessing file

getCurrentBlockHeader

IBlockHeader getCurrentBlockHeader()

This returns the current (active) block (physical record) header. Since most users have no interest in physical records, this method should not be used.

Returns:

the current block header.

gotoEventNumber

EvioEvent gotoEventNumber(int evNumber)
                   throws java.io.IOException,
                          EvioException

Go to a specific event in the file. The events are numbered 1..N. This number is transient--it is not part of the event as stored in the evio file. In versions 4 and up this is just a wrapper on getEvent(int).

Parameters:

evNumber - the event number in a 1..N counting sense, from the start of the file.

Returns:

the specified event in file or null if there's an error or nothing at that event #.

Throws:

java.io.IOException - if failed file access

EvioException - if object closed

toXMLFile

WriteStatus toXMLFile(java.lang.String path)
               throws java.io.IOException,
                      EvioException

Rewrite the file to XML (not including dictionary and "first" event).

Parameters:

path - the path to the XML file.

Returns:

the status of the write.

Throws:

java.io.IOException - if failed file access

EvioException - if object closed

toXMLFile

WriteStatus toXMLFile(java.lang.String path,
                      boolean hex)
               throws java.io.IOException,
                      EvioException

Rewrite the file to XML (not including dictionary and "first" event).

Parameters:

path - the path to the XML file.

hex - if true, ints get displayed in hexadecimal

Returns:

the status of the write.

Throws:

java.io.IOException - if failed file access

EvioException - if object closed

toXMLFile

WriteStatus toXMLFile(java.lang.String path,
                      IEvioProgressListener progressListener)
               throws java.io.IOException,
                      EvioException

Rewrite the file to XML (not including dictionary and "first" event).

Parameters:

path - the path to the XML file.

progressListener - and optional progress listener, can be null.

Returns:

the status of the write.

Throws:

java.io.IOException - if failed file access

EvioException - if object closed

See Also:

IEvioProgressListener

toXMLFile

WriteStatus toXMLFile(java.lang.String path,
                      IEvioProgressListener progressListener,
                      boolean hex)
               throws java.io.IOException,
                      EvioException

Rewrite the file to XML (not including dictionary and "first" event).

Parameters:

path - the path to the XML file.

progressListener - and optional progress listener, can be null.

hex - if true, ints get displayed in hexadecimal

Returns:

the status of the write.

Throws:

java.io.IOException - if failed file access

EvioException - if object closed

See Also:

IEvioProgressListener

getEventCount

int getEventCount()
           throws java.io.IOException,
                  EvioException

This is the number of events in the file/buffer. Any dictionary or first event are not included in the count.

Returns:

the number of events in the file/buffer.

Throws:

java.io.IOException - if failed file access

EvioException - if read failure; if object closed

getBlockCount

int getBlockCount()
           throws EvioException

This is the number of records in the file/buffer including the empty record or trailer at the end.

Returns:

the number of records in the file/buffer (estimate for version 3 files).

Throws:

EvioException - if object closed.