org.jlab.coda.jevio

Class EvioCompactReader

java.lang.Object

org.jlab.coda.jevio.EvioCompactReader

All Implemented Interfaces:

IEvioCompactReader

public class EvioCompactReader
extends java.lang.Object
implements IEvioCompactReader

This class is used to read an evio version 4 formatted file or buffer and extract specific evio containers (bank, seg, or tagseg) with actual data in them given a tag/num pair. It is theoretically thread-safe if synced is true. It is designed to be fast and does NOT do a full deserialization on each event examined.

Author:

timmer

Field Summary

Fields inherited from interface org.jlab.coda.jevio.IEvioCompactReader

MAGIC_OFFSET, VERSION_MASK, VERSION_OFFSET

Constructor Summary

Constructors

Constructor and Description
EvioCompactReader(java.nio.ByteBuffer byteBuffer) Constructor for reading a buffer.
EvioCompactReader(java.nio.ByteBuffer byteBuffer, boolean synced) Constructor for reading a buffer with option of removing synchronization for much greater speed.
EvioCompactReader(java.nio.ByteBuffer byteBuffer, EvioNodeSource pool, boolean synced) Constructor for reading a buffer with option of removing synchronization for much greater speed.
EvioCompactReader(java.io.File file) Constructor for reading an event file.
EvioCompactReader(java.lang.String path) Constructor for reading an event file.

Method Summary

Modifier and Type	Method and Description
java.nio.ByteBuffer	addStructure(int eventNumber, java.nio.ByteBuffer addBuffer) This method adds an evio container (bank, segment, or tag segment) as the last structure contained in an event.
void	close() This sets the position to its initial value and marks reader as closed.
long	fileSize() Get the size of the file being read, in bytes.
int	getBlockCount() This is the number of blocks in the file/buffer including the empty block 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.
java.nio.ByteBuffer	getData(EvioNode node) Get the data associated with an evio structure in ByteBuffer form.
java.nio.ByteBuffer	getData(EvioNode node, boolean copy) Get the data associated with an evio structure in ByteBuffer form.
EvioXMLDictionary	getDictionary() Get the evio dictionary if is there is one.
java.lang.String	getDictionaryXML() Get the XML format dictionary is there is one.
EvioNode	getEvent(int eventNumber) Get the EvioNode object associated with a particular event number.
java.nio.ByteBuffer	getEventBuffer(int eventNumber) Get an evio bank or event in ByteBuffer form.
java.nio.ByteBuffer	getEventBuffer(int eventNumber, boolean copy) 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.
java.nio.ByteOrder	getFileByteOrder() When reading a file, this method's return value is the byte order of the evio data in the file.
IBlockHeader	getFirstBlockHeader() This returns the FIRST block (or record) header.
java.nio.MappedByteBuffer	getMappedByteBuffer() Get the memory mapped buffer corresponding to the event file.
java.lang.String	getPath() Get the path to the file.
EvioNode	getScannedEvent(int eventNumber) Get the EvioNode object associated with a particular event number which has been scanned so all substructures are contained in the node.allNodes list.
EvioNode	getScannedEvent(int eventNumber, EvioNodeSource nodeSource) Get the EvioNode object associated with a particular event number which has been scanned so all substructures are contained in the node.allNodes list.
java.nio.ByteBuffer	getStructureBuffer(EvioNode node) Get an evio structure (bank, seg, or tagseg) in ByteBuffer form.
java.nio.ByteBuffer	getStructureBuffer(EvioNode node, boolean copy) Get an evio structure (bank, seg, or tagseg) in ByteBuffer form.
boolean	hasDictionary() Does this evio file have an associated XML dictionary?
boolean	isClosed() Has IEvioCompactReader.close() been called (without reopening by calling IEvioCompactReader.setBuffer(ByteBuffer))?
boolean	isCompressed() Is the data in the file/buffer compressed?
boolean	isFile() Is this reader reading a file?
java.nio.ByteBuffer	removeEvent(int eventNumber) This method removes the data of the given event from the buffer.
java.nio.ByteBuffer	removeStructure(EvioNode removeNode) This method removes the data, represented by the given node, from the buffer.
java.util.List<EvioNode>	searchEvent(int eventNumber, int tag, int num) This method searches the specified event in a file/buffer and returns a list of objects each of which contain information about a single evio structure which matches the given tag and num.
java.util.List<EvioNode>	searchEvent(int eventNumber, java.lang.String dictName, EvioXMLDictionary dictionary) This method searches the specified event in a file/buffer and returns a list of objects each of which contain information about a single evio structure which matches the given dictionary entry name.
void	setBuffer(java.nio.ByteBuffer buf) This method can be used to avoid creating additional EvioCompactReader objects by reusing this one with another buffer.
void	setBuffer(java.nio.ByteBuffer buf, EvioNodeSource pool) This method can be used to avoid creating additional EvioCompactReader objects by reusing this one with another buffer.
void	toFile(java.io.File file) Save the internal byte buffer to the given file (overwrites existing file).
void	toFile(java.lang.String fileName) Save the internal byte buffer to the given file (overwrites existing file).

Methods inherited from class java.lang.Object

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

Constructor Detail

EvioCompactReader

public EvioCompactReader(java.lang.String path)
                  throws EvioException,
                         java.io.IOException

Constructor for reading an event file.

Parameters:

path - the full path to the file that contains events. For writing event files, use an EventWriter object.

Throws:

java.io.IOException - if read failure

EvioException - if file arg is null

See Also:

EventWriter

EvioCompactReader

public EvioCompactReader(java.io.File file)
                  throws EvioException,
                         java.io.IOException

Constructor for reading an event file.

Parameters:

file - the file that contains events.

Throws:

java.io.IOException - if read failure

EvioException - if file arg is null; file is too large;

java.nio.BufferUnderflowException - if not enough data;

EvioException - if failure to parse first block header; unsupported evio version; reading file not supported for version 6+.

See Also:

EventWriter

EvioCompactReader

public EvioCompactReader(java.nio.ByteBuffer byteBuffer)
                  throws EvioException

Constructor for reading a buffer.

Parameters:

byteBuffer - the buffer that contains events.

Throws:

EvioException - if buffer arg is null; failure to read first block header

See Also:

EventWriter

EvioCompactReader

public EvioCompactReader(java.nio.ByteBuffer byteBuffer,
                         boolean synced)
                  throws EvioException

Constructor for reading a buffer with option of removing synchronization for much greater speed.

Parameters:

byteBuffer - the buffer that contains events.

synced - if true, methods are synchronized for thread safety, else false.

Throws:

java.nio.BufferUnderflowException - if not enough buffer data;

EvioException - if buffer arg is null; failure to parse first block header; unsupported evio version.

See Also:

EventWriter

EvioCompactReader

public EvioCompactReader(java.nio.ByteBuffer byteBuffer,
                         EvioNodeSource pool,
                         boolean synced)
                  throws EvioException

Constructor for reading a buffer with option of removing synchronization for much greater speed.

Parameters:

byteBuffer - the buffer that contains events.

pool - the object pool to get EvioNode objects from.

synced - if true, methods are synchronized for thread safety, else false.

Throws:

java.nio.BufferUnderflowException - if not enough buffer data;

EvioException - if buffer arg is null; failure to parse first block header; unsupported evio version.

See Also:

EventWriter

Method Detail

isFile

public boolean isFile()

Is this reader reading a file?

Specified by:

isFile in interface IEvioCompactReader

Returns:

true if reading file, false if reading buffer

isCompressed

public boolean isCompressed()

Is the data in the file/buffer compressed?

Specified by:

isCompressed in interface IEvioCompactReader

Returns:

true if data is compressed.

setBuffer

public void setBuffer(java.nio.ByteBuffer buf)
               throws EvioException

This method can be used to avoid creating additional EvioCompactReader objects by reusing this one with another buffer. The method IEvioCompactReader.close() should be called before calling this.

Specified by:

setBuffer in interface IEvioCompactReader

Parameters:

buf - ByteBuffer to be read

Throws:

EvioException - if arg is null; if failure to read first block header; buf not in evio format.

setBuffer

public void setBuffer(java.nio.ByteBuffer buf,
                      EvioNodeSource pool)
               throws EvioException

This method can be used to avoid creating additional EvioCompactReader objects by reusing this one with another buffer. The given buffer may NOT have compressed data or an exception will be thrown. The method IEvioCompactReader.close() is called before anything else. The pool is not reset in this method. Caller may do that prior to calling method.

Specified by:

setBuffer in interface IEvioCompactReader

Parameters:

buf - ByteBuffer to be read

pool - pool of EvioNode objects to use when parsing buf to avoid garbage collection.

Throws:

EvioException - if arg is null; if failure to read first block header; buf not in evio format.

isClosed

public boolean isClosed()

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

Specified by:

isClosed in interface IEvioCompactReader

Returns:

true if this object closed, else false.

getByteOrder

public java.nio.ByteOrder getByteOrder()

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

Specified by:

getByteOrder in interface IEvioCompactReader

Returns:

byte order of the file/buffer being read.

getEvioVersion

public int getEvioVersion()

Get the evio version number.

Specified by:

getEvioVersion in interface IEvioCompactReader

Returns:

evio version number.

getPath

public java.lang.String getPath()

Get the path to the file.

Specified by:

getPath in interface IEvioCompactReader

Returns:

path to the file

getFileByteOrder

public java.nio.ByteOrder getFileByteOrder()

When reading a file, this method's return value is the byte order of the evio data in the file.

Specified by:

getFileByteOrder in interface IEvioCompactReader

Returns:

byte order of the evio data in the file.

getDictionaryXML

public java.lang.String getDictionaryXML()
                                  throws EvioException

Get the XML format dictionary is there is one.

Specified by:

getDictionaryXML in interface IEvioCompactReader

Returns:

XML format dictionary, else null.

Throws:

EvioException - if object closed and dictionary still unread

getDictionary

public EvioXMLDictionary getDictionary()
                                throws EvioException

Get the evio dictionary if is there is one.

Specified by:

getDictionary in interface IEvioCompactReader

Returns:

evio dictionary if exists, else null.

Throws:

EvioException - if object closed and dictionary still unread

hasDictionary

public boolean hasDictionary()

Does this evio file have an associated XML dictionary?

Specified by:

hasDictionary in interface IEvioCompactReader

Returns:

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

getMappedByteBuffer

public java.nio.MappedByteBuffer getMappedByteBuffer()

Get the memory mapped buffer corresponding to the event file.

Specified by:

getMappedByteBuffer in interface IEvioCompactReader

Returns:

the memory mapped buffer corresponding to the event file.

getByteBuffer

public java.nio.ByteBuffer getByteBuffer()

Get the byte buffer being read directly or corresponding to the event file.

Specified by:

getByteBuffer in interface IEvioCompactReader

Returns:

the byte buffer being read directly or corresponding to the event file.

fileSize

public 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.

Specified by:

fileSize in interface IEvioCompactReader

Returns:

the file size in bytes

getEvent

public EvioNode getEvent(int eventNumber)

Get the EvioNode object associated with a particular event number.

Specified by:

getEvent in interface IEvioCompactReader

Parameters:

eventNumber - number of event (place in file/buffer) starting at 1.

Returns:

EvioNode object associated with a particular event number, or null if there is none.

getScannedEvent

public EvioNode getScannedEvent(int eventNumber)

Get the EvioNode object associated with a particular event number which has been scanned so all substructures are contained in the node.allNodes list.

Specified by:

getScannedEvent in interface IEvioCompactReader

Parameters:

eventNumber - number of event (place in file/buffer) starting at 1.

Returns:

EvioNode object associated with a particular event number, or null if there is none.

getScannedEvent

public EvioNode getScannedEvent(int eventNumber,
                                EvioNodeSource nodeSource)

Get the EvioNode object associated with a particular event number which has been scanned so all substructures are contained in the node.allNodes list.

Specified by:

getScannedEvent in interface IEvioCompactReader

Parameters:

eventNumber - number of event (place in file/buffer) starting at 1.

nodeSource - source of EvioNode objects to use while parsing evio data.

Returns:

EvioNode object associated with a particular event number, or null if there is none.

getFirstBlockHeader

public IBlockHeader getFirstBlockHeader()

This returns the FIRST block (or record) header. (Not the file header of evio version 6+ files).

Specified by:

getFirstBlockHeader in interface IEvioCompactReader

Returns:

the first block header.

searchEvent

public java.util.List<EvioNode> searchEvent(int eventNumber,
                                            int tag,
                                            int num)
                                     throws EvioException

This method searches the specified event in a file/buffer and returns a list of objects each of which contain information about a single evio structure which matches the given tag and num.

Specified by:

searchEvent in interface IEvioCompactReader

Parameters:

eventNumber - place of event in buffer (starting with 1)

tag - tag to match

num - num to match

Returns:

list of EvioNode objects corresponding to matching evio structures (empty if none found)

Throws:

EvioException - if bad arg value(s); if object closed

searchEvent

public java.util.List<EvioNode> searchEvent(int eventNumber,
                                            java.lang.String dictName,
                                            EvioXMLDictionary dictionary)
                                     throws EvioException

This method searches the specified event in a file/buffer and returns a list of objects each of which contain information about a single evio structure which matches the given dictionary entry name.

Specified by:

searchEvent in interface IEvioCompactReader

Parameters:

eventNumber - place of event in buffer (starting with 1)

dictName - name of dictionary entry to search for

dictionary - dictionary to use; if null, use dictionary with file/buffer

Returns:

list of EvioNode objects corresponding to matching evio structures (empty if none found)

Throws:

EvioException - if dictName is null; if dictName is an invalid dictionary entry; if dictionary is null and none provided in file/buffer being read; if object closed

removeEvent

public java.nio.ByteBuffer removeEvent(int eventNumber)
                                throws EvioException

This method removes the data of the given event from the buffer. It also marks any existing EvioNodes representing the event and its descendants as obsolete. They must not be used anymore.

If the constructor of this reader read in data from a file, it will now switch to using a new, internal buffer which is returned by this method or can be retrieved by calling IEvioCompactReader.getByteBuffer(). It will not change the file originally used. A new file can be created by calling either the IEvioCompactReader.toFile(String) or IEvioCompactReader.toFile(java.io.File) methods.

Specified by:

removeEvent in interface IEvioCompactReader

Parameters:

eventNumber - number of event to remove from buffer

Returns:

new ByteBuffer created and updated to reflect the event removal

Throws:

EvioException - if eventNumber < 1; if event number does not correspond to existing event; if object closed; if node was not found in any event; if internal programming error

removeStructure

public java.nio.ByteBuffer removeStructure(EvioNode removeNode)
                                    throws EvioException

This method removes the data, represented by the given node, from the buffer. It also marks the node and its descendants as obsolete. They must not be used anymore.

If the constructor of this reader read in data from a file, it will now switch to using a new, internal buffer which is returned by this method or can be retrieved by calling IEvioCompactReader.getByteBuffer(). It will not change the file originally used. A new file can be created by calling either the IEvioCompactReader.toFile(String) or IEvioCompactReader.toFile(java.io.File) methods.

Specified by:

removeStructure in interface IEvioCompactReader

Parameters:

removeNode - evio structure to remove from buffer

Returns:

new ByteBuffer (perhaps created) and updated to reflect the node removal

Throws:

EvioException - if object closed; if node was not found in any event; if internal programming error

addStructure

public java.nio.ByteBuffer addStructure(int eventNumber,
                                        java.nio.ByteBuffer addBuffer)
                                 throws EvioException

This method adds an evio container (bank, segment, or tag segment) as the last structure contained in an event. It is the responsibility of the caller to make sure that the buffer argument contains valid evio data (only data representing the structure to be added - not in file format with block header and the like) which is compatible with the type of data stored in the given event.

To produce such evio data use BaseStructure.write(ByteBuffer), BaseStructure.write(ByteBuffer) or BaseStructure.write(ByteBuffer) depending on whether a bank, seg, or tagseg is being added.

A note about files here. If the constructor of this reader read in data from a file, it will now switch to using a new, internal buffer which is returned by this method or can be retrieved by calling IEvioCompactReader.getByteBuffer(). It will not expand the file originally used. A new file can be created by calling either the IEvioCompactReader.toFile(String) or IEvioCompactReader.toFile(java.io.File) methods.

The given buffer argument must be ready to read with its position and limit defining the limits of the data to copy. This method is synchronized due to the bulk, relative puts.

Specified by:

addStructure in interface IEvioCompactReader

Parameters:

eventNumber - number of event to which addBuffer is to be added

addBuffer - buffer containing evio data to add (not evio file format, i.e. no block headers)

Returns:

a new ByteBuffer object which is created and filled with all the data including what was just added.

Throws:

EvioException - if eventNumber < 1; if addBuffer is null; if addBuffer arg is empty or has non-evio format; if addBuffer is opposite endian to current event buffer; if added data is not the proper length (i.e. multiple of 4 bytes); if the event number does not correspond to an existing event; if there is an internal programming error; if object closed

getData

public java.nio.ByteBuffer getData(EvioNode node)
                            throws EvioException

Get the data associated with an evio structure in ByteBuffer form. The returned buffer is a view into this reader's buffer (no copy done). Changes in one will affect the other.

Specified by:

getData in interface IEvioCompactReader

Parameters:

node - evio structure whose data is to be retrieved

Returns:

ByteBuffer object containing data. Position and limit are set for reading.

Throws:

EvioException - if object closed or node arg is null.

getData

public java.nio.ByteBuffer getData(EvioNode node,
                                   boolean copy)
                            throws EvioException

Get the data associated with an evio structure in ByteBuffer form. Depending on the copy argument, the returned buffer will either be a copy of or a view into the data of this reader's buffer.

This method is synchronized due to the bulk, relative gets & puts.

Specified by:

getData in interface IEvioCompactReader

Parameters:

node - evio structure whose data is to be retrieved

copy - if true, then return a copy as opposed to a view into this reader object's buffer.

Returns:

ByteBuffer object containing data. Position and limit are set for reading.

Throws:

EvioException - if object closed

getEventBuffer

public java.nio.ByteBuffer getEventBuffer(int eventNumber)
                                   throws EvioException

Get an evio bank or event in ByteBuffer form. The returned buffer is a view into the data of this reader's buffer.

Specified by:

getEventBuffer in interface IEvioCompactReader

Parameters:

eventNumber - number of event of interest

Returns:

ByteBuffer object containing bank's/event's bytes. Position and limit are set for reading.

Throws:

EvioException - if eventNumber < 1; if the event number does not correspond to an existing event; if object closed

getEventBuffer

public java.nio.ByteBuffer getEventBuffer(int eventNumber,
                                          boolean copy)
                                   throws EvioException

Get an evio bank or event in ByteBuffer form. Depending on the copy argument, the returned buffer will either be a copy of or a view into the data of this reader's buffer.

Specified by:

getEventBuffer in interface IEvioCompactReader

Parameters:

eventNumber - number of event of interest

copy - if true, then return a copy as opposed to a view into this reader object's buffer.

Returns:

ByteBuffer object containing bank's/event's bytes. Position and limit are set for reading.

Throws:

EvioException - if eventNumber < 1; if the event number does not correspond to an existing event; if object closed

getStructureBuffer

public java.nio.ByteBuffer getStructureBuffer(EvioNode node)
                                       throws EvioException

Get an evio structure (bank, seg, or tagseg) in ByteBuffer form. The returned buffer is a view into the data of this reader's buffer.

Specified by:

getStructureBuffer in interface IEvioCompactReader

Parameters:

node - node object representing evio structure of interest

Returns:

ByteBuffer object containing bank's/event's bytes. Position and limit are set for reading.

Throws:

EvioException - if node is null; if object closed

getStructureBuffer

public java.nio.ByteBuffer getStructureBuffer(EvioNode node,
                                              boolean copy)
                                       throws EvioException

Get an evio structure (bank, seg, or tagseg) in ByteBuffer form. Depending on the copy argument, the returned buffer will either be a copy of or a view into the data of this reader's buffer.

Specified by:

getStructureBuffer in interface IEvioCompactReader

Parameters:

node - node object representing evio structure of interest

copy - if true, then return a copy as opposed to a view into this reader object's buffer.

Returns:

ByteBuffer object containing structure's bytes. Position and limit are set for reading.

Throws:

EvioException - if node is null; if object closed

close

public void close()

This sets the position to its initial value and marks reader as closed.

Specified by:

close in interface IEvioCompactReader

getEventCount

public int getEventCount()

This is the number of events in the file/buffer. Any dictionary event is not included in the count. In versions 3 and earlier, it is not computed unless asked for, and if asked for it is computed and cached.

Specified by:

getEventCount in interface IEvioCompactReader

Returns:

the number of events in the file/buffer.

getBlockCount

public int getBlockCount()

This is the number of blocks in the file/buffer including the empty block at the end.

Specified by:

getBlockCount in interface IEvioCompactReader

Returns:

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

toFile

public void toFile(java.lang.String fileName)
            throws EvioException,
                   java.io.IOException

Save the internal byte buffer to the given file (overwrites existing file).

Specified by:

toFile in interface IEvioCompactReader

Parameters:

fileName - name of file to write

Throws:

EvioException - if fileName arg is null; if object closed

java.io.IOException - if error writing to file

toFile

public void toFile(java.io.File file)
            throws EvioException,
                   java.io.IOException

Save the internal byte buffer to the given file (overwrites existing file).

Specified by:

toFile in interface IEvioCompactReader

Parameters:

file - object of file to write

Throws:

EvioException - if file arg is null; if object closed

java.io.IOException - if error writing to file