Package org.apache.jena.dboe.transaction

Class TransMonitor

java.lang.Object

org.apache.jena.dboe.transaction.TransMonitor

All Implemented Interfaces:

TransactionalComponent

public class TransMonitor
extends Object
implements TransactionalComponent

This class is stateless in the transaction but it records counts of every TransactionalComponent operations. For each operation called "ABC" there is a member field "counterABC".

Field Summary

Fields

Modifier and Type	Field	Description
LongAdder	counterAbort
LongAdder	counterAttach
LongAdder	counterBegin
LongAdder	counterCleanStart
LongAdder	counterCommit
LongAdder	counterCommitEnd
LongAdder	counterCommitPrepare
LongAdder	counterComplete
LongAdder	counterDetach
LongAdder	counterFinishRecovery
LongAdder	counterGetComponentId
LongAdder	counterPromote
LongAdder	counterRecover
LongAdder	counterShutdown
LongAdder	counterStartRecovery

Constructor Summary

Constructors

Constructor	Description
TransMonitor(ComponentId cid)

Method Summary

Modifier and Type	Method	Description
void	abort(Transaction transaction)	Abort a transaction (undo the effect of a transaction)
void	attach(SysTransState systemState)	Set the current thread to be in the transaction.
void	begin(Transaction transaction)	Start a transaction; return an identifier for this components use.
void	cleanStart()	Indicate that no recovery is being done (the journal thinks everything was completed last time)
void	commit(Transaction transaction)	Commit a transaction (make durable).
void	commitEnd(Transaction transaction)	Signal all commits on all components are done and replay from the journal will not happen.
ByteBuffer	commitPrepare(Transaction transaction)	Prepare for a commit.
void	complete(Transaction transaction)	Finalization - the coordinator will not mention the transaction again.
SysTransState	detach()	Detach this component from the transaction of the current thread and return some internal state that can be used in a future call of TransactionalComponent.attach(SysTransState)
void	finishRecovery()	End of the recovery phase
Map<String,Long>	getAll()	Get a copy of the counters with current values.
ComponentId	getComponentId()	Every component instance must supplied a unique number.
void	print()	Print the counters state.
void	print(PrintStream ps)	Print the counters state.
boolean	promote(Transaction transaction)	Promote a component in a transaction.
void	recover(ByteBuffer ref)	Notification that ref was really committed and is being recovered.
void	reset()	Reset all counters to zero
void	shutdown()	Shutdown component, aborting any in-progress transactions.
void	startRecovery()

Methods inherited from class java.lang.Object

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

Field Details

counterGetComponentId

public LongAdder counterGetComponentId

counterStartRecovery

public LongAdder counterStartRecovery

counterRecover

public LongAdder counterRecover

counterFinishRecovery

public LongAdder counterFinishRecovery

counterCleanStart

public LongAdder counterCleanStart

counterBegin

public LongAdder counterBegin

counterPromote

public LongAdder counterPromote

counterCommitPrepare

public LongAdder counterCommitPrepare

counterCommit

public LongAdder counterCommit

counterCommitEnd

public LongAdder counterCommitEnd

counterAbort

public LongAdder counterAbort

counterComplete

public LongAdder counterComplete

counterDetach

public LongAdder counterDetach

counterAttach

public LongAdder counterAttach

counterShutdown

public LongAdder counterShutdown

Constructor Details

TransMonitor

public TransMonitor(ComponentId cid)

Method Details

reset

public void reset()

Reset all counters to zero

getAll

public Map<String,Long> getAll()

Get a copy of the counters with current values. The values are as of the point of this being called and are not changed by any later calls to monitored operations.

print

public void print()

Print the counters state.

print

public void print(PrintStream ps)

Print the counters state.

getComponentId

public ComponentId getComponentId()

Description copied from interface: TransactionalComponent

Every component instance must supplied a unique number. It is used to route journal entries to subsystems, including across restarts/recovery. Uniqueness scope is within the same TransactionCoordinator, and the same across restarts.

If a component imposes the rule of one-per-TransactionCoordinator, the same number can be used (if different from all other component type instances).

If a component can have multiple instances per TransactionCoordinator, for example indexes, each must have a unique instance id.

Specified by:

getComponentId in interface TransactionalComponent

startRecovery

public void startRecovery()

Specified by:

startRecovery in interface TransactionalComponent

recover

public void recover(ByteBuffer ref)

Description copied from interface: TransactionalComponent

Notification that ref was really committed and is being recovered.

Specified by:

recover in interface TransactionalComponent

Parameters:

ref - Same bytes as were written during prepare originally.

finishRecovery

public void finishRecovery()

Description copied from interface: TransactionalComponent

End of the recovery phase

Specified by:

finishRecovery in interface TransactionalComponent

cleanStart

public void cleanStart()

Description copied from interface: TransactionalComponent

Indicate that no recovery is being done (the journal thinks everything was completed last time)

Specified by:

cleanStart in interface TransactionalComponent

begin

public void begin(Transaction transaction)

Description copied from interface: TransactionalComponent

Start a transaction; return an identifier for this components use.

Specified by:

begin in interface TransactionalComponent

promote

public boolean promote(Transaction transaction)

Description copied from interface: TransactionalComponent

Promote a component in a transaction.

May return "false" for "can't do that" if the transaction can not be promoted.

May throw UnsupportedOperationException if promotion is not supported.

Specified by:

promote in interface TransactionalComponent

commitPrepare

public ByteBuffer commitPrepare(Transaction transaction)

Description copied from interface: TransactionalComponent

Prepare for a commit. Returns some bytes that will be written to the journal. The journal remains valid until TransactionalComponent.commitEnd(org.apache.jena.dboe.transaction.txn.Transaction) is called.

Specified by:

commitPrepare in interface TransactionalComponent

commit

public void commit(Transaction transaction)

Description copied from interface: TransactionalComponent

Commit a transaction (make durable). The transaction will commit and not abort. Other components may not have committed yet and recovery may occur still causing replay of the commit step.

Specified by:

commit in interface TransactionalComponent

commitEnd

public void commitEnd(Transaction transaction)

Description copied from interface: TransactionalComponent

Signal all commits on all components are done and replay from the journal will not happen. The component can clear up now.

Specified by:

commitEnd in interface TransactionalComponent

abort

public void abort(Transaction transaction)

Description copied from interface: TransactionalComponent

Abort a transaction (undo the effect of a transaction)

Specified by:

abort in interface TransactionalComponent

complete

public void complete(Transaction transaction)

Description copied from interface: TransactionalComponent

Finalization - the coordinator will not mention the transaction again.

Specified by:

complete in interface TransactionalComponent

detach

public SysTransState detach()

Description copied from interface: TransactionalComponent

Detach this component from the transaction of the current thread and return some internal state that can be used in a future call of TransactionalComponent.attach(SysTransState)

After this call, the component is not in a transaction but the existing transaction still exists. The thread may start a new transaction; that transaction is completely independent of the detached transaction.

Returns null if the current thread not in a transaction. The component may return null to indicate it has no state. The return system state should be used in a call to TransactionalComponent.attach(SysTransState) and the transaction ended in the usual way.

Specified by:

detach in interface TransactionalComponent

attach

public void attach(SysTransState systemState)

Description copied from interface: TransactionalComponent

Set the current thread to be in the transaction. The systemState must be obtained from a call of TransactionalComponent.detach(). This method can only be called once per systemState.

Specified by:

attach in interface TransactionalComponent

shutdown

public void shutdown()

Description copied from interface: TransactionalComponent

Shutdown component, aborting any in-progress transactions. This operation is not guaranteed to be called.

Specified by:

shutdown in interface TransactionalComponent