com.arjuna.ats.arjuna.coordinator
Class AbstractRecord

java.lang.Object
  com.arjuna.ats.arjuna.StateManager
      com.arjuna.ats.arjuna.coordinator.AbstractRecord

Direct Known Subclasses:

LastResourceRecord, RecoveryAbstractRecord, com.arjuna.ats.arjuna.RecoveryRecord

public abstract class AbstractRecord

extends StateManager

Abstract Record Class This class provides an abstract template that defines the interface that the atomic action system uses to notify objects that various state transitions have occurred as the 2PC protocol executes. Record types derived from this class manage certain properties of objects such as recovery information, concurrency control information etc, and all must redifine the operations defined here as abstract to take appropriate action. Many functions are declared pure virtual to force a definition to occur in any derived class. These are currently all functions dealing with atomic action coordination as well as the following list management functions: typeIs: returns the record type of the instance. This is one of the values of the enumerated type Record_type value: Some arbitrary value associated with the record instance merge: Used when two records need to merge togethor. Currently this is only used by CadaverRecords to merge information from PersistenceRecords shouldAdd: returns TRUE is the record should be added to the list FALSE if it should be discarded shouldMerge: returns TRUE is the two records should be merged into a single record, FALSE if it should be discarded shouldReplace: returns TRUE if the record should replace an existing one, FALSE otherwise.

Since:

1.0.

Version:

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

Author:

Mark Little (mark@arjuna.com)

Field Summary

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

modifyingActions, objectName, objectUid, smAttributes, usingActions

Constructor Summary

protected	AbstractRecord() Creates a 'blank' abstract record.
protected	AbstractRecord(Uid storeUid) Create a new instance with the specified paramaters.
protected	AbstractRecord(Uid storeUid, java.lang.String objType, int otype) Create a new instance with the specified paramaters.

Method Summary

abstract void	alter(AbstractRecord a) Alter the current record with the one presented.
ClassName	className() Only used for crash recovery, so most records don't need it.
static AbstractRecord	create(ClassName cName)
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.
boolean	equals(AbstractRecord ar) Determine if two records are equal in that both are the same type and have the same order value (determined via 'order()').
boolean	forgetHeuristic() Forget any heuristic outcome which this implementation may have produced.
protected AbstractRecord	getNext()
protected AbstractRecord	getPrevious() These few functions are link manipulation primitives used by the RecordList processing software to chain instances together.
java.lang.String	getTypeOfObject() Return the type of the abstract record.
boolean	greaterThan(AbstractRecord ar) Determine if two records are greater than in that both are the same type and their Uids are greater than.
boolean	lessThan(AbstractRecord ar) Determine if two records are less than in that both are the same type and their Uids are less than.
abstract void	merge(AbstractRecord a) Merge the current record with the one presented.
abstract int	nestedAbort() A rollback of a nested transaction has occurred.
int	nestedCleanup() Cleanup is called if a nested is detected to be an orphan.
abstract int	nestedCommit() A commit of a nested transaction has occurred.
int	nestedOnePhaseCommit() Perform a nested one phase commit.
abstract int	nestedPrepare() A prepare for a nested transaction has occurred.
Uid	order() Return the Uid of this abstract record so that it can be ordered in the intentions list.
void	print(java.io.PrintWriter strm) Write information about this specific instance to the specified stream.
boolean	propagateOnAbort() Determine if records are discarded on action abort or must be propagated to parents.
boolean	propagateOnCommit() Determine if records are discarded on action commit or must be propagated to parents.
void	replace(AbstractRecord a) The current record is about to replace the one presented.
boolean	restore_state(InputObjectState os, int i) 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 i) 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 void	setNext(AbstractRecord ar) Set the next element in the list to the specified instance.
protected void	setPrevious(AbstractRecord ar) Set the previous element in the list to the specified instance.
abstract void	setValue(java.lang.Object o)
abstract boolean	shouldAdd(AbstractRecord a) Should we add the record presented to the intentions list?
abstract boolean	shouldAlter(AbstractRecord a) Should we alter the current record with the one presented?
abstract boolean	shouldMerge(AbstractRecord a) Should we merge the current record with the one presented?
abstract boolean	shouldReplace(AbstractRecord a) Should we replace the record presented with the current record?
abstract int	topLevelAbort() A rollback of a top-level transaction has occurred.
int	topLevelCleanup() Cleanup is called if a top-level action is detected to be an orphan.
abstract int	topLevelCommit() A commit of a top-level transaction has occurred.
int	topLevelOnePhaseCommit() Perform a top-level one phase commit.
abstract int	topLevelPrepare() A prepare for a top-level transaction has occurred.
java.lang.String	type() Re-implementation of abstract methods inherited from base class.
abstract int	typeIs()
abstract java.lang.Object	value() If this abstract record caused a heuristic then it should return an object which implements HeuristicInformation

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractRecord

protected AbstractRecord(Uid storeUid,
                         java.lang.String objType,
                         int otype)

Create a new instance with the specified paramaters.

See Also:

ObjectType

AbstractRecord

protected AbstractRecord(Uid storeUid)

Create a new instance with the specified paramaters.

AbstractRecord

protected AbstractRecord()

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

Method Detail

typeIs

public abstract int typeIs()

Returns:

RecordType value.

value

public abstract java.lang.Object value()

If this abstract record caused a heuristic then it should return an object which implements HeuristicInformation

Returns:

Object to be used to order.

setValue

public abstract void setValue(java.lang.Object o)

className

public ClassName className()

Only used for crash recovery, so most records don't need it.

Returns:

ClassName to identify this abstract record.

nestedAbort

public abstract int nestedAbort()

A rollback of a nested transaction has occurred.

Returns:

TwoPhaseOutcome to indicate success/failure.

See Also:

TwoPhaseOutcome

nestedCommit

public abstract int nestedCommit()

A commit of a nested transaction has occurred.

Returns:

TwoPhaseOutcome to indicate success/failure.

See Also:

TwoPhaseOutcome

nestedPrepare

public abstract int nestedPrepare()

A prepare for a nested transaction has occurred.

Returns:

TwoPhaseOutcome to indicate success/failure.

See Also:

TwoPhaseOutcome

topLevelAbort

public abstract int topLevelAbort()

A rollback of a top-level transaction has occurred.

Returns:

TwoPhaseOutcome to indicate success/failure.

See Also:

TwoPhaseOutcome

topLevelCommit

public abstract int topLevelCommit()

A commit of a top-level transaction has occurred.

Returns:

TwoPhaseOutcome to indicate success/failure.

See Also:

TwoPhaseOutcome

topLevelPrepare

public abstract int topLevelPrepare()

A prepare for a top-level transaction has occurred.

Returns:

TwoPhaseOutcome to indicate success/failure.

See Also:

TwoPhaseOutcome

order

public Uid order()

Return the Uid of this abstract record so that it can be ordered in the intentions list. This is also the Uid that the record was saved with in the object store.

Returns:

Uid for this instance.

See Also:

Uid

getTypeOfObject

public java.lang.String getTypeOfObject()

Return the type of the abstract record. Used in ordering the instances in the intentions list. This is also the type that the record was saved with in the object store.

Returns:

String representing type.

propagateOnAbort

public boolean propagateOnAbort()

Determine if records are discarded on action abort or must be propagated to parents.

Returns:

true if the record should be propagated to the parent transaction if the current transaction rolls back, false otherwise. The default is false.

propagateOnCommit

public boolean propagateOnCommit()

Determine if records are discarded on action commit or must be propagated to parents.

Returns:

true if the record should be propagated to the parent transaction if the current transaction commits, false otherwise. The default is true.

equals

public final boolean equals(AbstractRecord ar)

Determine if two records are equal in that both are the same type and have the same order value (determined via 'order()').

Returns:

true if equal, false otherwise.

lessThan

public final boolean lessThan(AbstractRecord ar)

Determine if two records are less than in that both are the same type and their Uids are less than.

Returns:

true if equal, false otherwise.

greaterThan

public final boolean greaterThan(AbstractRecord ar)

Determine if two records are greater than in that both are the same type and their Uids are greater than.

Returns:

true if equal, false otherwise.

topLevelCleanup

public int topLevelCleanup()

Cleanup is called if a top-level action is detected to be an orphan. NOTE nested actions are never orphans since their parents would be aborted we may as well abort them as well.

Returns:

TwoPhaseOutcome as default is the same as topLevelAbort.

nestedCleanup

public int nestedCleanup()

Cleanup is called if a nested is detected to be an orphan. NOTE nested actions are never orphans since their parents would be aborted we may as well abort them as well.

Returns:

TwoPhaseOutcome as default is the same as nestedAbort.

doSave

public 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. 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).

Returns:

true if it should be saved, false otherwise. false is the default.

type

public java.lang.String type()

Re-implementation of abstract methods inherited from base class.

Overrides:

type in class StateManager

print

public void print(java.io.PrintWriter strm)

Write information about this specific instance to the specified stream.

Overrides:

print in class StateManager

save_state

public boolean save_state(OutputObjectState os,
                          int i)

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.

Overrides:

save_state in class StateManager

Returns:

true if successful, false otherwise.

restore_state

public boolean restore_state(InputObjectState os,
                             int i)

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.

Overrides:

restore_state in class StateManager

Returns:

true if successful, false otherwise.

forgetHeuristic

public boolean forgetHeuristic()

Forget any heuristic outcome which this implementation may have produced.

Returns:

true by default. If false is returned then the instance must be remembered by the transaction (in the log) in order for recovery to retry later or for a system administrator to be able to determine which resources have not been successfully completed.

nestedOnePhaseCommit

public int nestedOnePhaseCommit()

Perform a nested one phase commit.

Returns:

TwoPhaseOutcome to indicate success/failure.

See Also:

TwoPhaseOutcome

topLevelOnePhaseCommit

public int topLevelOnePhaseCommit()

Perform a top-level one phase commit.

Returns:

TwoPhaseOutcome to indicate success/failure.

See Also:

TwoPhaseOutcome

create

public static AbstractRecord create(ClassName cName)

Returns:

a newly created instance of the derived class specified by the ClassName, or null if there is nothing defined in the inventory.

See Also:

ClassName

merge

public abstract void merge(AbstractRecord a)

Merge the current record with the one presented.

alter

public abstract void alter(AbstractRecord a)

Alter the current record with the one presented.

shouldAdd

public abstract boolean shouldAdd(AbstractRecord a)

Should we add the record presented to the intentions list?

Returns:

true if the record should be added, false otherwise.

shouldAlter

public abstract boolean shouldAlter(AbstractRecord a)

Should we alter the current record with the one presented?

Returns:

true if the record should be altered, false otherwise.

shouldMerge

public abstract boolean shouldMerge(AbstractRecord a)

Should we merge the current record with the one presented?

Returns:

true if the record should be merged, false otherwise.

shouldReplace

public abstract boolean shouldReplace(AbstractRecord a)

Should we replace the record presented with the current record?

Returns:

true if the record should be replaced, false otherwise.

replace

public void replace(AbstractRecord a)

The current record is about to replace the one presented. This method is invoked to give the current record a chance to copy information, for example, from the record being replaced.

getPrevious

protected final AbstractRecord getPrevious()

These few functions are link manipulation primitives used by the RecordList processing software to chain instances together.

Returns:

the previous element in the intentions list, or null.

getNext

protected final AbstractRecord getNext()

Returns:

the next element in the intentions list, or null.

setPrevious

protected final void setPrevious(AbstractRecord ar)

Set the previous element in the list to the specified instance.

setNext

protected final void setNext(AbstractRecord ar)

Set the next element in the list to the specified instance.