org.apache.jackrabbit.core.journal

Class FileRecordLog

java.lang.Object

org.apache.jackrabbit.core.journal.FileRecordLog

public class FileRecordLog
extends Object

A file record log is a file containing Records. Every file record log contains a header with the following physical layout:

Physical Record Layout

Byte 1	Byte 2	Byte 3	Byte 4
'J'	'L'	'O'	'G'
MAJOR		MINOR
START REVISION

After this header, zero or more ReadRecords follow.

Constructor Summary

Constructors

Constructor and Description
FileRecordLog(File logFile) Create a new instance of this class.

Method Summary

Modifier and Type	Method and Description
long	append(String journalId, String producerId, InputStream in, int length) Append a record to this log.
void	close() Close this log.
boolean	contains(long revision) Return a flag indicating whether this record log contains a certain revision.
boolean	exceeds(long size) Return a flag indicating whether this record log exceeds a given size.
long	getLastRevision() Return the last revision.
long	getPreviousRevision() Return the previous revision.
void	init(long previousRevision) Initialize this record log by writing a header containing the previous revision.
boolean	isNew() Return a flag indicating whether this record log is new.
ReadRecord	read(NamespaceResolver resolver, NamePathResolver npResolver) Read the file record at the current seek position.
void	seek(long revision) Seek an entry.

Methods inherited from class java.lang.Object

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

Constructor Detail

FileRecordLog

public FileRecordLog(File logFile)
              throws IOException

Create a new instance of this class. Opens a record log in read-only mode.

Parameters:

logFile - file containing record log

Throws:

IOException - if an I/O error occurs

Method Detail

init

public void init(long previousRevision)
          throws IOException

Initialize this record log by writing a header containing the previous revision.

Throws:

IOException

contains

public boolean contains(long revision)

Return a flag indicating whether this record log contains a certain revision.

Parameters:

revision - revision to look for

Returns:

true if this record log contain a certain revision; false otherwise

isNew

public boolean isNew()

Return a flag indicating whether this record log is new.

Returns:

true if this record log is new; false otherwise

exceeds

public boolean exceeds(long size)

Return a flag indicating whether this record log exceeds a given size.

seek

public void seek(long revision)
          throws IOException

Seek an entry. This is an operation that allows the underlying input stream to be sequentially scanned and must therefore not be called twice.

Parameters:

revision - revision to seek

Throws:

IOException - if an I/O error occurs

read

public ReadRecord read(NamespaceResolver resolver,
                       NamePathResolver npResolver)
                throws IOException

Read the file record at the current seek position.

Parameters:

resolver - namespace resolver

Returns:

file record

Throws:

IOException - if an I/O error occurs

append

public long append(String journalId,
                   String producerId,
                   InputStream in,
                   int length)
            throws IOException

Append a record to this log. Returns the revision following this record.

Parameters:

journalId - journal identifier

producerId - producer identifier

in - record to add

length - record length

Throws:

IOException - if an I/O error occurs

getPreviousRevision

public long getPreviousRevision()

Return the previous revision. This is the last revision preceding the first revision in this log.

Returns:

previous revision

getLastRevision

public long getLastRevision()

Return the last revision. This is the last revision in this log.

Returns:

last revision

close

public void close()

Close this log.