com.sleepycat.je.log

Class LastFileReader

java.lang.Object

com.sleepycat.je.log.FileReader

com.sleepycat.je.log.LastFileReader

public class LastFileReader
extends FileReader

LastFileReader traverses the last log file, doing checksums and looking for the end of the log. Different log types can be registered with it and it will remember the last occurrence of targetted entry types.

Field Summary

Fields inherited from class com.sleepycat.je.log.FileReader

anticipateChecksumErrors, cksumValidator, currentEntryHeader, currentEntryOffset, currentEntryPrevOffset, envImpl, eof, fileManager, nextEntryOffset, readBufferFileEnd, readBufferFileNum, readBufferFileStart, startLsn

Constructor Summary

Constructors

Constructor and Description
LastFileReader(EnvironmentImpl env, int readBufferSize) This file reader is always positioned at the last file.
LastFileReader(EnvironmentImpl env, int readBufferSize, java.lang.Long specificFileNumber) Ctor which allows passing in the file number we want to read to the end of.

Method Summary

Methods

Modifier and Type	Method and Description
long	getEndOfLog()
LogEntryType	getEntryType()
long	getLastSeen(LogEntryType type)
long	getLastValidLsn()
long	getPrevOffset()
protected void	initStartingPosition(long endOfFileLsn, java.lang.Long singleFileNum) Override so that we always start at the last file.
protected boolean	processEntry(java.nio.ByteBuffer entryBuffer) Validate the checksum on each entry, see if we should remember the LSN of this entry.
boolean	readNextEntry() readNextEntry will stop at a bad entry.
void	setEndOfFile()
void	setTargetType(LogEntryType type) Tell the reader that we are interested in these kind of entries.

Methods inherited from class com.sleepycat.je.log.FileReader

getAndResetNReads, getLastEntrySize, getLastLsn, getNRepeatIteratorReads, getNumRead, isTargetEntry, resyncReader, setAlwaysValidateChecksum, threadSafeBufferPosition, threadSafeBufferPosition

Methods inherited from class java.lang.Object

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

Constructor Detail

LastFileReader

public LastFileReader(EnvironmentImpl env,
              int readBufferSize)
               throws java.io.IOException,
                      DatabaseException

This file reader is always positioned at the last file.

Throws:

java.io.IOException

DatabaseException

LastFileReader

public LastFileReader(EnvironmentImpl env,
              int readBufferSize,
              java.lang.Long specificFileNumber)
               throws java.io.IOException,
                      DatabaseException

Ctor which allows passing in the file number we want to read to the end of. This is used by the ScavengerFileReader when it encounters a bad log record in the middle of a file.

Throws:

java.io.IOException

DatabaseException

Method Detail

initStartingPosition

protected void initStartingPosition(long endOfFileLsn,
                        java.lang.Long singleFileNum)
                             throws java.io.IOException,
                                    DatabaseException

Override so that we always start at the last file.

Overrides:

initStartingPosition in class FileReader

Throws:

java.io.IOException

DatabaseException

setEndOfFile

public void setEndOfFile()
                  throws java.io.IOException,
                         DatabaseException

Throws:

java.io.IOException

DatabaseException

getEndOfLog

public long getEndOfLog()

Returns:

The LSN to be used for the next log entry.

getLastValidLsn

public long getLastValidLsn()

getPrevOffset

public long getPrevOffset()

getEntryType

public LogEntryType getEntryType()

setTargetType

public void setTargetType(LogEntryType type)

Tell the reader that we are interested in these kind of entries.

getLastSeen

public long getLastSeen(LogEntryType type)

Returns:

The last LSN seen in the log for this kind of entry, or null.

processEntry

protected boolean processEntry(java.nio.ByteBuffer entryBuffer)

Validate the checksum on each entry, see if we should remember the LSN of this entry.

Specified by:

processEntry in class FileReader

Returns:

true if this entry should be returned

readNextEntry

public boolean readNextEntry()
                      throws DatabaseException,
                             java.io.IOException

readNextEntry will stop at a bad entry.

Overrides:

readNextEntry in class FileReader

Returns:

true if an element has been read.

Throws:

DatabaseException

java.io.IOException