com.sleepycat.je.txn

Class UndoReader

java.lang.Object

com.sleepycat.je.txn.UndoReader

public class UndoReader
extends Object

Convenience class to package together the different steps and fields needed for reading a log entry for undoing. Is used for both txn aborts and recovery undos.

Field Summary

Fields

Modifier and Type	Field and Description
DatabaseImpl	db
LN	ln
LNLogEntry<?>	logEntry
int	logEntrySize

Method Summary

Modifier and Type	Method and Description
static UndoReader	create(EnvironmentImpl envImpl, long undoLsn, Map<DatabaseId,DatabaseImpl> undoDatabases) Set up an UndoReader when doing an undo or txn partial rollback for a live txn.
static UndoReader	createForRecovery(LNFileReader reader, DbTree dbMapTree) Set up an UndoReader when doing a recovery partial rollback.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

logEntry

public final LNLogEntry<?> logEntry

ln

public final LN ln

logEntrySize

public final int logEntrySize

db

public final DatabaseImpl db

Method Detail

create

public static UndoReader create(EnvironmentImpl envImpl,
                                long undoLsn,
                                Map<DatabaseId,DatabaseImpl> undoDatabases)

Set up an UndoReader when doing an undo or txn partial rollback for a live txn.

Never returns null. The DB ID of the LN must be present in undoDatabases, or a fatal exception is thrown.

createForRecovery

public static UndoReader createForRecovery(LNFileReader reader,
                                           DbTree dbMapTree)

Set up an UndoReader when doing a recovery partial rollback. In that case, we have a file reader positioned at the pertinent log entry.

This method calls DbTree.getDb. The caller is responsible for calling DbTree.releaseDb on the db field.

Null is returned if the DB ID of the LN has been deleted.

toString

public String toString()

Overrides:

toString in class Object