com.bigdata.service

Class AbstractTransactionService.TxState

java.lang.Object

com.bigdata.service.AbstractTransactionService.TxState

All Implemented Interfaces:

ITxState, ITxState0

Enclosing class:

AbstractTransactionService

public class AbstractTransactionService.TxState
extends Object
implements ITxState

Transaction state as maintained by the ITransactionService.

Note: The commitTime and revisionTime are requested by the local transaction manager for single phase commits, which means that this class could only know their values for a distributed transaction commit. Hence they are not represented here.

Field Summary

Fields

Modifier and Type	Field and Description
protected ReentrantLock	lock A per-transaction lock used to serialize operations on a given transaction.
long	tx The transaction identifier.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractTransactionService.TxState(long tx, long readCommitTime)

Method Summary

Methods

Modifier and Type	Method and Description
void	declareResources(UUID dataService, String[] resource) Declares resources on a data service instance on which the transaction will write.
boolean	equals(Object o) True iff they are the same object or have the same start timestamp.
long	getCommitTime() The commit time assigned to a distributed read-write transaction during the commit protocol.
int	getDataServiceCount() Return the #of IDataServices on which a read-write transaction has executed an operation.
protected UUID[]	getDataServiceUUIDs() The set of DataServices on which the transaction has written.
long	getReadsOnCommitTime() The timestamp of the commit point against which this transaction is reading.
String[]	getResources() Return the resources declared by the transaction.
long	getStartTimestamp() The start time for the transaction as assigned by a centralized transaction manager service.
int	hashCode() The hash code is based on the getStartTimestamp().
boolean	isAborted() A transaction is "aborted" iff it has successfully aborted.
boolean	isActive() A transaction is "active" when it is created and remains active until it prepares or aborts.
boolean	isCommitted() A transaction is "committed" iff it has successfully committed.
boolean	isComplete() A transaction is "complete" once has either committed or aborted.
boolean	isPrepared() A transaction is "prepared" once it has been successfully validated and has fulfilled its pre-commit contract for a multi-stage commit protocol.
boolean	isReadOnly() Return true iff this is a read-only transaction.
boolean	isStartedOn(UUID dataServiceUUID) Return true iff the dataService identified by the UUID is one on which this transaction has been started.
protected void	setCommitTime(long commitTime) Sets the assigned commit time.
void	setRunState(RunState newval) Change the RunState.
String	toString() Returns a string representation of the transaction state.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

tx

public final long tx

The transaction identifier.

lock

protected final ReentrantLock lock

A per-transaction lock used to serialize operations on a given transaction. You need to hold this lock for most of the operations on this class, including any access to the RunState.

Note: DO NOT attempt to acquire the outer AbstractTransactionService.lock if you are already holding this lock. This is a lock ordering problem and can result in a deadlock.

Constructor Detail

AbstractTransactionService.TxState

protected AbstractTransactionService.TxState(long tx,
                                  long readCommitTime)

Parameters:

tx - The assigned transaction identifier.

readCommitTime - The commit time associated with the commit point against which this transaction will read (may be ZERO if there are no commit points, must not be negative).

Method Detail

setRunState

public void setRunState(RunState newval)

Change the RunState.

Parameters:

newval - The new RunState.

Throws:

IllegalArgumentException - if the argument is null.

IllegalStateException - if the state transition is not allowed.

See Also:

RunState.isTransitionAllowed(RunState)

getStartTimestamp

public final long getStartTimestamp()

Description copied from interface: ITxState0

The start time for the transaction as assigned by a centralized transaction manager service. Transaction start times are unique and also serve as transaction identifiers. Note that this is NOT the time at which a transaction begins executing on a specific journal as the same transaction may start at different moments on different journals and typically will only start on some journals rather than all.

Specified by:

getStartTimestamp in interface ITxState0

Returns:

The transaction start time.

See Also:

TODO Rename since the sign indicates read-only vs read-write and hence it can not be directly interpreted as a commitTime? (e.g., getTxId()).

getReadsOnCommitTime

public final long getReadsOnCommitTime()

Description copied from interface: ITxState0

The timestamp of the commit point against which this transaction is reading.

Note: This is not currently available on a cluster. In that context, we wind up with the same timestamp for #startTime and #readsOnCommitTime which causes cache pollution for things which cache based on #readsOnCommitTime.

Specified by:

getReadsOnCommitTime in interface ITxState0

See Also:

Refactor native long tx id to thin object, Add cache for access to historical index views on the Journal by name and commitTime.

getCommitTime

public long getCommitTime()

The commit time assigned to a distributed read-write transaction during the commit protocol.

Returns:

The assigned commit time.

Throws:

IllegalStateException - if the commit time has not been assigned.

setCommitTime

protected void setCommitTime(long commitTime)

Sets the assigned commit time.

Parameters:

commitTime - The assigned commit time.

getResources

public String[] getResources()

Return the resources declared by the transaction.

isStartedOn

public boolean isStartedOn(UUID dataServiceUUID)

Return true iff the dataService identified by the UUID is one on which this transaction has been started.

Parameters:

dataServiceUUID - The UUID identifying an IDataService.

Returns:

true if this transaction has been started on that IDataService. false for read-only transactions.

getDataServiceUUIDs

protected UUID[] getDataServiceUUIDs()

The set of DataServices on which the transaction has written.

Throws:

IllegalStateException - if not a read-write transaction.

hashCode

public final int hashCode()

The hash code is based on the getStartTimestamp().

Overrides:

hashCode in class Object

equals

public final boolean equals(Object o)

True iff they are the same object or have the same start timestamp.

Overrides:

equals in class Object

Parameters:

o - Another transaction object.

declareResources

public final void declareResources(UUID dataService,
                    String[] resource)

Declares resources on a data service instance on which the transaction will write.

Parameters:

dataService - The data service identifier.

resource - An array of named resources on the data service on which the transaction will write (or at least for which it requires an exclusive write lock).

Throws:

IllegalStateException - if the transaction is read-only.

IllegalStateException - if the transaction is not active.

getDataServiceCount

public final int getDataServiceCount()

Return the #of IDataServices on which a read-write transaction has executed an operation.

Returns:

The #of IDataService.

Throws:

IllegalStateException - if the transaction is read-only.

IllegalMonitorStateException - if the caller does not hold the lock.

toString

public final String toString()

Returns a string representation of the transaction state.

Overrides:

toString in class Object

isReadOnly

public final boolean isReadOnly()

Description copied from interface: ITxState

Return true iff this is a read-only transaction.

Specified by:

isReadOnly in interface ITxState

isActive

public final boolean isActive()

Description copied from interface: ITxState

A transaction is "active" when it is created and remains active until it prepares or aborts. An active transaction accepts READ, WRITE, DELETE, PREPARE and ABORT requests.

Specified by:

isActive in interface ITxState

Returns:

True iff the transaction is active.

isPrepared

public final boolean isPrepared()

Description copied from interface: ITxState

A transaction is "prepared" once it has been successfully validated and has fulfilled its pre-commit contract for a multi-stage commit protocol. An prepared transaction accepts COMMIT and ABORT requests.

Note: This is a transient state. Once the transaction has prepared it will transition to either COMMIT or ABORT and this method will no longer report true.

Specified by:

isPrepared in interface ITxState

Returns:

True iff the transaction is prepared to commit.

isComplete

public final boolean isComplete()

Description copied from interface: ITxState

A transaction is "complete" once has either committed or aborted. A completed transaction does not accept any requests.

Specified by:

isComplete in interface ITxState

Returns:

True iff the transaction is completed.

isCommitted

public final boolean isCommitted()

Description copied from interface: ITxState

A transaction is "committed" iff it has successfully committed. A committed transaction does not accept any requests.

Specified by:

isCommitted in interface ITxState

Returns:

True iff the transaction is committed.

isAborted

public final boolean isAborted()

Description copied from interface: ITxState

A transaction is "aborted" iff it has successfully aborted. An aborted transaction does not accept any requests.

Specified by:

isAborted in interface ITxState

Returns:

True iff the transaction is aborted.