fabric.store

Class TransactionManager

java.lang.Object

fabric.store.TransactionManager

public class TransactionManager
extends java.lang.Object

Constructor Summary

Constructors

Constructor and Description
TransactionManager(ObjectDB database)

Method Summary

Modifier and Type	Method and Description
void	abortTransaction(Principal worker, long transactionID) Instruct the transaction manager that the given transaction is aborting
void	commitTransaction(RemoteIdentity<RemoteWorker> workerIdentity, long transactionID) Execute the commit phase of two phase commit.
ObjectGlob	getGlob(long onum, RemoteWorker subscriber) Returns a Glob containing the specified object.
ObjectGroup	getGroup(Principal principal, RemoteWorker subscriber, long onum) Returns an ObjectGroup containing the specified object.
long[]	newOnums(Principal worker, int num)
void	prepare(Principal worker, PrepareRequest req) Execute the prepare phase of two phase commit.

Methods inherited from class java.lang.Object

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

Constructor Detail

TransactionManager

public TransactionManager(ObjectDB database)

Method Detail

abortTransaction

public void abortTransaction(Principal worker,
                             long transactionID)
                      throws AccessException

Instruct the transaction manager that the given transaction is aborting

Throws:

AccessException

commitTransaction

public void commitTransaction(RemoteIdentity<RemoteWorker> workerIdentity,
                              long transactionID)
                       throws TransactionCommitFailedException

Execute the commit phase of two phase commit.

Throws:

TransactionCommitFailedException

prepare

public void prepare(Principal worker,
                    PrepareRequest req)
             throws TransactionPrepareFailedException

Execute the prepare phase of two phase commit. Validates the transaction to make sure that no conflicts would occur if this transaction were committed. Once prepare returns successfully, the corresponding transaction can only fail if the coordinator aborts it.

The prepare method must check a large number of conditions:

• Neither creates, updates, nor reads can have pending commits, i.e. none of them can contain objects for which other transactions have been prepared but not committed or aborted.
• The worker has appropriate permissions to read/write/create
• Created objects don't already exist
• Updated objects cannot have been read since the proposed commit time.
• Updated objects do not have valid outstanding promises
• Modified and read objects do exist
• Read objects are still valid (version numbers match)
• TODO: duplicate objects within sets / between sets?

Parameters:

worker - The worker requesting the prepare

Throws:

TransactionPrepareFailedException - If the transaction would cause a conflict or if the worker is insufficiently privileged to execute the transaction.

getGlob

public ObjectGlob getGlob(long onum,
                          RemoteWorker subscriber)
                   throws AccessException

Returns a Glob containing the specified object. All surrogates referenced by any object in the group will also be in the group. This ensures that the worker will not reveal information when dereferencing surrogates.

Parameters:

subscriber - If non-null, then the given worker will be subscribed to the object as a dissemination node.

Throws:

AccessException

getGroup

public ObjectGroup getGroup(Principal principal,
                            RemoteWorker subscriber,
                            long onum)
                     throws AccessException

Returns an ObjectGroup containing the specified object. All surrogates referenced by any object in the group will also be in the group. This ensures that the worker will not reveal information when dereferencing surrogates.

Parameters:

principal - The principal performing the read.

subscriber - If non-null, then the given worker will be subscribed to the object as a worker.

onum - The onum for an object that should be in the group.

handler - Used to track read statistics.

Throws:

AccessException

newOnums

public long[] newOnums(Principal worker,
                       int num)
                throws AccessException

Throws:

AccessException - if the principal is not allowed to create objects on this store.