com.sleepycat.je.log

Class BasicVersionedWriteLoggable

java.lang.Object

com.sleepycat.je.log.BasicVersionedWriteLoggable

All Implemented Interfaces:

Loggable, VersionedWriteLoggable

Direct Known Subclasses:

DatabaseId, Matchpoint, ReplicatedDatabaseConfig, Trace

public abstract class BasicVersionedWriteLoggable
extends Object
implements VersionedWriteLoggable

A basic implementation of VersionedWriteLoggable that provides for writing in a single format by default. Starting with log version 9, as specified by LogEntryType.LOG_VERSION_REPLICATE_OLDER, loggable classes whose log format has changed since the previous log version will need to override the VersionedWriteLoggable.getLastFormatChange(), VersionedWriteLoggable.getLogSize(int, boolean) and VersionedWriteLoggable.writeToLog(ByteBuffer, int, boolean) methods to support writing the entry in earlier log formats.

Constructor Summary

Constructors

Constructor and Description
BasicVersionedWriteLoggable() Creates an instance of this class.

Method Summary

Modifier and Type	Method and Description
int	getLogSize()
boolean	hasReplicationFormat() Returns whether this format has a variant that is optimized for replication.
boolean	isReplicationFormatWorthwhile(ByteBuffer logBuffer, int srcVersion, int destVersion) Returns whether it is worthwhile to materialize and then re-serialize a log entry in a format optimized for replication.
void	writeToLog(ByteBuffer logBuffer) Serialize this object into the buffer.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.sleepycat.je.log.VersionedWriteLoggable

getEmbeddedLoggables, getLastFormatChange, getLogSize, writeToLog

Methods inherited from interface com.sleepycat.je.log.Loggable

dumpLog, getTransactionId, logicalEquals, readFromLog

Constructor Detail

BasicVersionedWriteLoggable

public BasicVersionedWriteLoggable()

Creates an instance of this class.

Method Detail

getLogSize

public int getLogSize()

Specified by:

getLogSize in interface Loggable

Returns:

number of bytes used to store this object.

writeToLog

public void writeToLog(ByteBuffer logBuffer)

Description copied from interface: Loggable

Serialize this object into the buffer.

Specified by:

writeToLog in interface Loggable

Parameters:

logBuffer - is the destination buffer

hasReplicationFormat

public boolean hasReplicationFormat()

Description copied from interface: VersionedWriteLoggable

Returns whether this format has a variant that is optimized for replication.

Specified by:

hasReplicationFormat in interface VersionedWriteLoggable

isReplicationFormatWorthwhile

public boolean isReplicationFormatWorthwhile(ByteBuffer logBuffer,
                                             int srcVersion,
                                             int destVersion)

Description copied from interface: VersionedWriteLoggable

Returns whether it is worthwhile to materialize and then re-serialize a log entry in a format optimized for replication. Implementations should attempt to check efficiently, without instantiating the log entry object. Some implementations will simply return false.

WARNING: The logBuffer position must not be changed by this method.

WARNING: The shared LogEntry object is used for calling this method, and this method must not change any of the fields in the object.

Specified by:

isReplicationFormatWorthwhile in interface VersionedWriteLoggable

Parameters:

logBuffer - contains the entry that would be re-serialized.

srcVersion - the log version of entry in logBuffer.

destVersion - the version that would be used for re-serialization.