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

java.lang.Object
  org.apache.derby.impl.store.raw.data.PageBasicOperation
      org.apache.derby.impl.store.raw.data.PhysicalUndoOperation

All Implemented Interfaces:

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

public class PhysicalUndoOperation
extends PageBasicOperation
implements Compensation

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

See Also:
Serialized Form
Format ID
LOGOP_PAGE_PHYSICAL_UNDO
                the formatId is written by FormatIdOutputStream when this object is
                written out by writeObject
Purpose
update a physiacl log operation
Upgrade

Disk Layout
PageBasicOperation	the super class
                OptionalData	none (compensation operation never have optional data)








Field Summary




private  PhysicalPageOperation
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




 
PhysicalUndoOperation()



          Return my format identifier.



protected 
PhysicalUndoOperation(BasePage page)



           



 
PhysicalUndoOperation(BasePage page,
                      PhysicalPageOperation op)



          Set up a compensation operation during run time rollback


 



Method Summary




 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
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 PageUndoOperation during recovery redo.



 java.lang.String
toString()



          DEBUG: Print self.


 
Methods inherited from class org.apache.derby.impl.store.raw.data.PageBasicOperation
findpage, getPage, getPageForRedoRecovery, getPageId, getPageVersion, needsRedo, readExternal, reclaimPrepareLocks, resetPageNumber, writeExternal
 
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
 
Methods inherited from interface java.io.Externalizable
readExternal, writeExternal
 





Field Detail



undoOp
private transient PhysicalPageOperation undoOp

The operation to be rolled back








Constructor Detail



PhysicalUndoOperation
protected PhysicalUndoOperation(BasePage page)





PhysicalUndoOperation
public PhysicalUndoOperation(BasePage page,
                             PhysicalPageOperation op)

Set up a compensation operation during run time rollback





PhysicalUndoOperation
public PhysicalUndoOperation()

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).





setUndoOp
public void setUndoOp(Undoable op)

Set up a PageUndoOperation 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 InputStream.
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








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





toString
public java.lang.String toString()

DEBUG: Print self.


Overrides:
toString in class PageBasicOperation