org.apache.derby.impl.store.raw.data

Class LogicalUndoOperation

java.lang.Object

org.apache.derby.impl.store.raw.data.PageBasicOperation

org.apache.derby.impl.store.raw.data.LogicalUndoOperation

All Implemented Interfaces:

java.io.Externalizable, java.io.Serializable, Formatable, TypedFormat, Compensation, Loggable, RePreparable

public class LogicalUndoOperation
extends PageBasicOperation
implements Compensation

LogicalUndoOperation is a compensation operation that rolls back the change of an LogicalUndoable operation. A LogicalUndoOperation itself is not undo-able, i.e, it is loggable but not undoable.

See Also:

Serialized Form

Format ID	LOGOP_PAGE_LOGICAL_UNDO the formatId is written by FormatIdOutputStream when this object is written out by writeObject
Purpose	undo a logical log operation
Upgrade
Disk Layout	PageBasicOperation the super class recordId(CompressedInt) the recordId of the changed row (this may not be the recordId during rollback if the record moved from one page to another) OptionalData none (compensation operation never have optional data)

Field Summary

Fields

Modifier and Type	Field and Description
protected int	recordId
private LogicalPageOperation	undoOp The operation to be rolled back

Fields inherited from class org.apache.derby.impl.store.raw.data.PageBasicOperation

containerHdl, foundHere, page

Fields inherited from interface org.apache.derby.iapi.store.raw.Loggable

ABORT, BI_LOG, CHECKSUM, COMMIT, COMPENSATION, FILE_RESOURCE, FIRST, LAST, PREPARE, RAWSTORE, XA_NEEDLOCK

Constructor Summary

Constructors

Modifier	Constructor and Description
	LogicalUndoOperation() Return my format identifier.
protected	LogicalUndoOperation(BasePage page)
	LogicalUndoOperation(BasePage page, int recordId, LogicalPageOperation op) Set up a compensation operation during run time rollback

Method Summary

Modifier and Type	Method and Description
void	doMe(Transaction xact, LogInstant instant, LimitObjectInput in) Apply the undo operation, in this implementation of the RawStore, it can only call the undoMe method of undoOp
ByteArray	getPreparedLog() the default for optional data is set to null.
int	getTypeFormatId() Get a universally unique identifier for the type of this object.
int	group() A page operation is a RAWSTORE log record
void	readExternal(java.io.ObjectInput in) Read this in
void	releaseResource(Transaction xact) Release latched page and any other resources acquired during a previous findpage, safe to call multiple times.
void	restoreMe(Transaction xact, BasePage undoPage, LogInstant CLRinstant, LimitObjectInput in) Undo the change indicated by this log operation and optional data.
void	setUndoOp(Undoable op) Set up a LogicalOperation during recovery redo.
java.lang.String	toString() DEBUG: Print self.
void	writeExternal(java.io.ObjectOutput out) Write this out.

Methods inherited from class org.apache.derby.impl.store.raw.data.PageBasicOperation

findpage, getPage, getPageForRedoRecovery, getPageId, getPageVersion, needsRedo, reclaimPrepareLocks, resetPageNumber

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.derby.iapi.store.raw.Loggable

needsRedo

Field Detail

recordId

protected int recordId

undoOp

private transient LogicalPageOperation undoOp

The operation to be rolled back

Constructor Detail

LogicalUndoOperation

protected LogicalUndoOperation(BasePage page)

LogicalUndoOperation

public LogicalUndoOperation(BasePage page,
                            int recordId,
                            LogicalPageOperation op)

Set up a compensation operation during run time rollback

LogicalUndoOperation

public LogicalUndoOperation()

Return my format identifier.

Method Detail

getTypeFormatId

public int getTypeFormatId()

Description copied from interface: TypedFormat

Get a universally unique identifier for the type of this object.

Specified by:

getTypeFormatId in interface TypedFormat

Returns:

The identifier. (A UUID stuffed in an array of 16 bytes).

writeExternal

public void writeExternal(java.io.ObjectOutput out)
                   throws java.io.IOException

Write this out.

Specified by:

writeExternal in interface java.io.Externalizable

Overrides:

writeExternal in class PageBasicOperation

Throws:

java.io.IOException - error writing to log stream

readExternal

public void readExternal(java.io.ObjectInput in)
                  throws java.io.IOException,
                         java.lang.ClassNotFoundException

Read this in

Specified by:

readExternal in interface java.io.Externalizable

Overrides:

readExternal in class PageBasicOperation

Throws:

java.io.IOException - error reading from log stream

java.lang.ClassNotFoundException - log stream corrupted

restoreMe

public void restoreMe(Transaction xact,
                      BasePage undoPage,
                      LogInstant CLRinstant,
                      LimitObjectInput in)

Description copied from class: PageBasicOperation

Undo the change indicated by this log operation and optional data. The page the undo should apply to is the latched undoPage. The undoPage must be the same page as the doMe page and the undo operation must restore the before image of the row that changed.
this can only be used under special circumstances: namely table level locking, and no internal or nested transaction, and all operations are rollec back with restoreMe instead of undoMe.
This method is here to support BeforeImageLogging

Specified by:

restoreMe in class PageBasicOperation

Parameters:

xact - the Transaction doing the rollback

undoPage - the page to rollback changes on

CLRinstant - the log instant of this (PageUndo) operation

in - optional data for the rollback operation

setUndoOp

public void setUndoOp(Undoable op)

Set up a LogicalOperation during recovery redo.

Specified by:

setUndoOp in interface Compensation

Parameters:

op - the Undoable operation

See Also:

Loggable.needsRedo(org.apache.derby.iapi.store.raw.Transaction)

doMe

public final void doMe(Transaction xact,
                       LogInstant instant,
                       LimitObjectInput in)
                throws StandardException,
                       java.io.IOException

Apply the undo operation, in this implementation of the RawStore, it can only call the undoMe method of undoOp

Specified by:

doMe in interface Loggable

Parameters:

xact - the Transaction that is doing the rollback

instant - the log instant of this undo operation

in - optional data

Throws:

java.io.IOException - Can be thrown by any of the methods of ObjectInput.

StandardException - Standard Derby policy.

releaseResource

public void releaseResource(Transaction xact)

Description copied from class: PageBasicOperation

Release latched page and any other resources acquired during a previous findpage, safe to call multiple times. In this RawStore implementataion, resource is acquired by a log operation in one of two places

during runtime or recovery undo in PageOperation.generateUndo() during recovery redo in PageBasicOperation.needsRedo()

Specified by:

releaseResource in interface Loggable

Overrides:

releaseResource in class PageBasicOperation

group

public int group()

Description copied from class: PageBasicOperation

A page operation is a RAWSTORE log record

Specified by:

group in interface Loggable

Overrides:

group in class PageBasicOperation

getPreparedLog

public final ByteArray getPreparedLog()

Description copied from class: PageBasicOperation

the default for optional data is set to null. If an operation has optional data, the operation need to prepare the optional data for this method. WARNING: If a log operation extends this class, and the operation has optional data, it MUST overwrite this method to return a ByteArray that contains the optional data.

Specified by:

getPreparedLog in interface Loggable

Overrides:

getPreparedLog in class PageBasicOperation

toString

public java.lang.String toString()

DEBUG: Print self.

Overrides:

toString in class PageBasicOperation