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 targeted entry types.

Nested Class Summary

Nested classes/interfaces inherited from class com.sleepycat.je.log.FileReader

FileReader.EOFException, FileReader.ReadWindow

Field Summary

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

cksumValidator, currentEntryHeader, currentEntryOffset, currentEntryPrevOffset, envImpl, eof, fileManager, forward, logger, nextEntryOffset, startLsn, window

Constructor Summary

Constructors

Constructor and Description
LastFileReader(EnvironmentImpl envImpl, int readBufferSize) This file reader is always positioned at the last file.

Method Summary

Modifier and Type	Method and Description
long	getEndOfLog()
LogEntryType	getEntryType()
long	getLastSeen(LogEntryType type)
long	getLastValidLsn()
long	getPrevOffset()
RestoreRequired	getRestoreRequired()
protected boolean	processEntry(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

entryIsReplicated, getAndResetNReads, getLastEntrySize, getLastLsn, getLastVlsn, getLogVersion, getNRepeatIteratorReads, getNumRead, handleGapInBackwardsScan, initStartingPosition, isTargetEntry, makeWindow, readNextEntryAllowExceptions, setAlwaysValidateChecksum, setBackwardPosition, setForwardPosition, skipData, skipEntry

Methods inherited from class java.lang.Object

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

Constructor Detail

LastFileReader

public LastFileReader(EnvironmentImpl envImpl,
                      int readBufferSize)
               throws DatabaseException

This file reader is always positioned at the last file. If no valid files exist (and invalid files do not contain data and can be moved away), we will not throw an exception. We will return false from the first call (all calls) to readNextEntry.

Throws:

DatabaseException - if the last file contains data and is invalid.

Method Detail

setEndOfFile

public void setEndOfFile()
                  throws IOException,
                         DatabaseException

Throws:

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(ByteBuffer entryBuffer)

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

Specified by:

processEntry in class FileReader

Parameters:

entryBuffer - A ByteBuffer that the logrec data and is positioned at the start of the logrec body (i.e., just after the logrec header).

Returns:

true if this entry should be returned to the caller of readNextEntry().

readNextEntry

public boolean readNextEntry()

readNextEntry will stop at a bad entry.

Overrides:

readNextEntry in class FileReader

Returns:

true if an element has been read.

getRestoreRequired

public RestoreRequired getRestoreRequired()