com.arjuna.ats.internal.arjuna.abstractrecords

Class PersistenceRecord

java.lang.Object

com.arjuna.ats.arjuna.StateManager

com.arjuna.ats.arjuna.coordinator.AbstractRecord

com.arjuna.ats.internal.arjuna.abstractrecords.RecoveryRecord

com.arjuna.ats.internal.arjuna.abstractrecords.PersistenceRecord

Direct Known Subclasses:

CadaverRecord, TxLogWritePersistenceRecord

public class PersistenceRecord
extends RecoveryRecord

A PersistenceRecord is created whenever a persistent object is created/read/modified within the scope of a transaction. It is responsible for ensuring that state changes are committed or rolled back on behalf of the object depending upon the outcome of the transaction.

Since:

JTS 1.0.

Version:

$Id: PersistenceRecord.java 2342 2006-03-30 13:06:17Z $

Author:

Mark Little (mark@arjuna.com)

Field Summary

Fields

Modifier and Type	Field and Description
protected static boolean	classicPrepare
static int	MAX_OBJECT_SIZE
protected boolean	shadowMade
protected ParticipantStore	targetParticipantStore
protected OutputObjectState	topLevelState

Fields inherited from class com.arjuna.ats.internal.arjuna.abstractrecords.RecoveryRecord

objectAddr, state

Fields inherited from class com.arjuna.ats.arjuna.StateManager

modifyingActions, objectModel, objectUid, usingActions

Constructor Summary

Constructors

Constructor and Description
PersistenceRecord() Creates a 'blank' persistence record.
PersistenceRecord(OutputObjectState os, ParticipantStore participantStore, StateManager sm) This constructor is used to create a new instance of PersistenceRecord.

Method Summary

Modifier and Type	Method and Description
boolean	doSave() Should this record be saved in the intentions list? If the record is saved, then it may be recovered later in the event of a failure.
void	print(PrintWriter strm) Write information about this specific instance to the specified stream.
boolean	restore_state(InputObjectState os, int ot) During recovery, the transaction log is given to the recovery system and it will recreate a transaction instance to perform necessary recovery actions.
boolean	save_state(OutputObjectState os, int ot) When the transaction is required to make the intentions list persistent, it scans the list and asks each record whether or not it requires state to be saved (by calling doSave).
protected boolean	shadowForced() Cadaver records force write shadows.
int	topLevelAbort() topLevelAbort may have to remove the persistent state that was written into the object store during the processing of topLevelPrepare.
int	topLevelCleanup() topLevelCleanup must leave the persistent state that was written in the object store during the processing of topLevelPrepare intact.
int	topLevelCommit() commit the state saved during the prepare phase.
int	topLevelPrepare() topLevelPrepare attempts to save the object.
String	type() Re-implementation of abstract methods inherited from base class.
int	typeIs() Redefintions of abstract functions inherited from RecoveryRecord.

Methods inherited from class com.arjuna.ats.internal.arjuna.abstractrecords.RecoveryRecord

alter, finalize, forgetAction, merge, nestedAbort, nestedCommit, nestedPrepare, setValue, shouldAdd, shouldAlter, shouldMerge, shouldReplace, value

Methods inherited from class com.arjuna.ats.arjuna.coordinator.AbstractRecord

create, equals, forgetHeuristic, getNext, getPrevious, getTypeOfObject, greaterThan, lessThan, nestedCleanup, nestedOnePhaseCommit, order, propagateOnAbort, propagateOnCommit, replace, setNext, setPrevious, topLevelOnePhaseCommit

Methods inherited from class com.arjuna.ats.arjuna.StateManager

activate, activate, cleanup, createLists, deactivate, deactivate, deactivate, destroy, disable, forgetAction, get_uid, getMutex, getObjectModel, getStore, getStoreRoot, loadObjectState, lockMutex, modified, objectType, packHeader, persist, rememberAction, setStatus, setupStore, setupStore, setupStore, status, terminate, tryLockMutex, unlockMutex, unpackHeader

Methods inherited from class java.lang.Object

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

Field Detail

MAX_OBJECT_SIZE

public static final int MAX_OBJECT_SIZE

See Also:

Constant Field Values

shadowMade

protected boolean shadowMade

targetParticipantStore

protected ParticipantStore targetParticipantStore

topLevelState

protected OutputObjectState topLevelState

classicPrepare

protected static final boolean classicPrepare

Constructor Detail

PersistenceRecord

public PersistenceRecord(OutputObjectState os,
                         ParticipantStore participantStore,
                         StateManager sm)

This constructor is used to create a new instance of PersistenceRecord.

PersistenceRecord

public PersistenceRecord()

Creates a 'blank' persistence record. This is used during crash recovery when recreating the prepared list of a server atomic action.

Method Detail

typeIs

public int typeIs()

Redefintions of abstract functions inherited from RecoveryRecord.

Overrides:

typeIs in class RecoveryRecord

Returns:

RecordType value.

topLevelAbort

public int topLevelAbort()

topLevelAbort may have to remove the persistent state that was written into the object store during the processing of topLevelPrepare. It then does the standard abort processing.

Overrides:

topLevelAbort in class RecoveryRecord

Returns:

TwoPhaseOutcome to indicate success/failure.

See Also:

TwoPhaseOutcome

topLevelCommit

public int topLevelCommit()

commit the state saved during the prepare phase.

Overrides:

topLevelCommit in class RecoveryRecord

Returns:

TwoPhaseOutcome to indicate success/failure.

See Also:

TwoPhaseOutcome

topLevelPrepare

public int topLevelPrepare()

topLevelPrepare attempts to save the object. It will either do this in the action intention list or directly in the object store by using the 'deactivate' function of the object depending upon the size of the state. To ensure that objects are correctly hidden while they are in an uncommitted state if we use the abbreviated protocol then we write an EMPTY object state as the shadow state - THIS MUST NOT BE COMMITTED. Instead we write_committed the one saved in the intention list. If the store cannot cope with being given an empty state we revert to the old protocol.

Overrides:

topLevelPrepare in class RecoveryRecord

Returns:

TwoPhaseOutcome to indicate success/failure.

See Also:

TwoPhaseOutcome

topLevelCleanup

public int topLevelCleanup()

topLevelCleanup must leave the persistent state that was written in the object store during the processing of topLevelPrepare intact. Crash recovery will take care of its resolution

Overrides:

topLevelCleanup in class AbstractRecord

Returns:

TwoPhaseOutcome as default is the same as topLevelAbort.

doSave

public boolean doSave()

Description copied from class: AbstractRecord

Should this record be saved in the intentions list? If the record is saved, then it may be recovered later in the event of a failure. Note, however, that the size of the intentions list on disk is critical to the performance of the system (disk I/O is a bottleneck).

Overrides:

doSave in class RecoveryRecord

Returns:

true

restore_state

public boolean restore_state(InputObjectState os,
                             int ot)

Description copied from class: AbstractRecord

During recovery, the transaction log is given to the recovery system and it will recreate a transaction instance to perform necessary recovery actions. This transaction will recreate the intentions list and give each recreated AbstractRecord the state that that was saved during transaction persistence. The base class will restore information that it needs from the log. Data items must be unpacked in the same order that they were packed.

Overrides:

restore_state in class RecoveryRecord

Returns:

true if successful, false otherwise.

save_state

public boolean save_state(OutputObjectState os,
                          int ot)

Description copied from class: AbstractRecord

When the transaction is required to make the intentions list persistent, it scans the list and asks each record whether or not it requires state to be saved (by calling doSave). If the answer is yes, then save_state is called and the record instance must save enough information to enable it to be restored from that state later. The basic AbstractRecord save_state will save common data that is required by the base class during recovery. If a derived class calls super.save_state then it must be called before packing any other data item.

Overrides:

save_state in class RecoveryRecord

Returns:

true if successful, false otherwise.

print

public void print(PrintWriter strm)

Description copied from class: AbstractRecord

Write information about this specific instance to the specified stream.

Overrides:

print in class RecoveryRecord

Parameters:

strm - the stream on which to output.

type

public String type()

Description copied from class: AbstractRecord

Re-implementation of abstract methods inherited from base class.

Overrides:

type in class RecoveryRecord

shadowForced

protected boolean shadowForced()

Cadaver records force write shadows. This operation supresses to abbreviated commit This should never return false