org.multiverse.stms.alpha.transactions.readonly
Class NonTrackingReadonlyAlphaTransaction

java.lang.Object
  org.multiverse.stms.AbstractTransaction<C,S>
      org.multiverse.stms.alpha.transactions.AbstractAlphaTransaction<ReadonlyConfiguration,org.multiverse.stms.AbstractTransactionSnapshot>
          org.multiverse.stms.alpha.transactions.readonly.AbstractReadonlyAlphaTransaction
              org.multiverse.stms.alpha.transactions.readonly.NonTrackingReadonlyAlphaTransaction

All Implemented Interfaces:

org.multiverse.api.Transaction, org.multiverse.MultiverseConstants, AlphaTransaction

public class NonTrackingReadonlyAlphaTransaction
extends AbstractReadonlyAlphaTransaction

A readonly AlphaTransaction implementation that doesn't track reads.

Unlike the MapUpdateAlphaTransaction a readonly transaction doesn't need track any reads done. This has the advantage that a readonly transaction consumes a lot less resources (so no collection needed to track all the reads) and commits are also a lot quicker (no dirtyness checking).

A disadvantage of not tracking reads, is that the retry/orelse functionality is not available in reaodnly transactions because the transaction has no clue which objects were loaded. So it also has no clue about the objects to listen to on a retry.

Although readonly transactions are isolated from update transactions from a correctness point of view, from a practical point of view a readonly transaction could be obstructed by an update transaction:

in the following scenario, the second load will fail with a LoadTooOldVersionException:

 T1 (ro): |load_X-----------------load_X|
 T2 (up):         |write_X|
 

In the future a version history will be added for previous committed data. So the chance that a old version is not available is going to decrease.

Author:

Peter Veentjer.

Nested Class Summary

static class

NonTrackingReadonlyAlphaTransaction.Factory

Field Summary

Fields inherited from class org.multiverse.stms.AbstractTransaction

config

Fields inherited from interface org.multiverse.MultiverseConstants

___SANITY_CHECKS_ENABLED

Constructor Summary

NonTrackingReadonlyAlphaTransaction(ReadonlyConfiguration config)

Method Summary

protected void	attach(AlphaTranlocal tranlocal)
protected boolean	dodoRegisterRetryLatch(org.multiverse.api.latches.Latch latch, long wakeupVersion)
protected AlphaTranlocal	findAttached(AlphaTransactionalObject txObject)

Methods inherited from class org.multiverse.stms.alpha.transactions.readonly.AbstractReadonlyAlphaTransaction

createLoadUncommittedException, doOpenForCommutingWrite, doOpenForConstruction, doOpenForRead, doOpenForWrite

Methods inherited from class org.multiverse.stms.alpha.transactions.AbstractAlphaTransaction

doRegisterRetryLatch, load, openForCommutingWrite, openForConstruction, openForRead, openForWrite

Methods inherited from class org.multiverse.stms.AbstractTransaction

abort, commit, doAbortActive, doAbortPrepared, doClear, doInit, doPrepare, endOr, endOrAndStartElse, getAttempt, getConfiguration, getReadVersion, getRemainingTimeoutNs, getSnapshot, getStatus, init, makeChangesPermanent, prepare, registerLifecycleListener, registerRetryLatch, restart, setAttempt, setRemainingTimeoutNs, startOr, storeSnapshot, takeSnapshot

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.multiverse.api.Transaction

abort, commit, getAttempt, getConfiguration, getReadVersion, getRemainingTimeoutNs, getStatus, prepare, registerLifecycleListener, registerRetryLatch, restart, setAttempt, setRemainingTimeoutNs

Constructor Detail

NonTrackingReadonlyAlphaTransaction

public NonTrackingReadonlyAlphaTransaction(ReadonlyConfiguration config)

Method Detail

dodoRegisterRetryLatch

protected boolean dodoRegisterRetryLatch(org.multiverse.api.latches.Latch latch,
                                         long wakeupVersion)

Specified by:

dodoRegisterRetryLatch in class AbstractAlphaTransaction<ReadonlyConfiguration,org.multiverse.stms.AbstractTransactionSnapshot>

findAttached

protected AlphaTranlocal findAttached(AlphaTransactionalObject txObject)

Specified by:

findAttached in class AbstractReadonlyAlphaTransaction

attach

protected void attach(AlphaTranlocal tranlocal)

Specified by:

attach in class AbstractReadonlyAlphaTransaction