Package com.arjuna.ats.internal.jts.resources

Class ResourceRecord

java.lang.Object
com.arjuna.ats.arjuna.StateManager
com.arjuna.ats.arjuna.coordinator.AbstractRecord
com.arjuna.ats.internal.jts.resources.ResourceRecord
public class ResourceRecord extends AbstractRecord
Arjuna abstract record to handle CORBA (SubtransactionAware)Resource interface. The OTS handling of Resources is bizarre (by Arjuna standards) and confusing Our current understanding is: Resources registered using 'register_resource' ONLY take part in top-level events SubtransactionAwareResources registered using 'register_subtran_aware' ONLY take part in commit/abort of the action in which they are registered - i.e. they DO NOT propagate automatically - the registering object must do the propagation itself using the parent arg in the 'commit_subtransaction' operation. If a SubtransactionAwareResource is registered with 'register_resource' then it will be propagated to the parent when the action commit. Otherwise it is only registered with the current transaction. Subtransactions do not have a 'prepare' phase which can thus lead to inconsistency. If they underwent the full 2-phase protocol (as they do in Arjuna), then all nested participants will have to repond successfully to prepare before they can be told to commit. The way the OTS mandates the protocol, we could tell some to commit before being told by another resource that it cannot commit! We then have to go through the resources and tell them to abort! May cause heuristic decisions! The only problem is if a resource which does not propagate causes a nested action to fail. SubtransactionAwareResources registered using 'register_resource' do appear to propagate. UGH! Braindead!
Since:
JTS 1.0.
Version:
$Id: ResourceRecord.java 2342 2006-03-30 13:06:17Z $
Author:
Mark Little (mark@arjuna.com)

  • Constructor Details

    • ResourceRecord

      public ResourceRecord(boolean propagate, Resource theResource, Coordinator myParent, Uid recCoordUid, ArjunaTransactionImple current)
      Constructor
      Parameters:
      propagate - tells us whether to propagate the resource at nested commit or not.
      theResource - is the proxy that allows us to call out to the object.
      myParent - is the proxy for the parent coordinator needed in commit_subtransaction.

    • ResourceRecord

      public ResourceRecord(boolean propagate, Resource theResource, Uid recCoordUid)

    • ResourceRecord

      public ResourceRecord()

  • Method Details

    • resourceHandle

      public final Resource resourceHandle()

    • propagateOnCommit

      public boolean propagateOnCommit()
      Description copied from class: AbstractRecord
      Determine if records are discarded on action commit or must be propagated to parents.
      Overrides:
      propagateOnCommit in class AbstractRecord
      Returns:
      true if the record should be propagated to the parent transaction if the current transaction commits, false otherwise. The default is true.

    • typeIs

      public int typeIs()
      Specified by:
      typeIs in class AbstractRecord
      Returns:
      RecordType value.

    • value

      public Object value()
      Description copied from class: AbstractRecord
      If this abstract record caused a heuristic then it should return an object which implements HeuristicInformation
      Specified by:
      value in class AbstractRecord
      Returns:
      Object to be used to order.

    • setValue

      public void setValue(Object o)
      Specified by:
      setValue in class AbstractRecord

    • nestedAbort

      public int nestedAbort()
      General nesting rules: Only SubtransactionAware resources get registered with nested actions. The ResourceRecord creator is assumed to ensure that plain Resources are only registered with the appropriate top level action. That said the _propagateRecord flag ensures that resources registered via register_subtran only take part in the action they where registered in after which they are dropped
      Specified by:
      nestedAbort in class AbstractRecord
      Returns:
      TwoPhaseOutcome to indicate success/failure.
      See Also:

    • nestedCommit

      public int nestedCommit()
      If this resource handles nesting this was done in prepare or it should be ignored. In either case returning FINISH_OK suffices.
      Specified by:
      nestedCommit in class AbstractRecord
      Returns:
      TwoPhaseOutcome to indicate success/failure.
      See Also:

    • nestedPrepare

      public int nestedPrepare()
      OTS does not use nested prepare at all! However, to make nested commit/abort clean we do commit_subtransaction here. Note that we only get a prepare from Arjuna if the action is to be committed so this is safe in Arjuna terms.
      Specified by:
      nestedPrepare in class AbstractRecord
      Returns:
      TwoPhaseOutcome to indicate success/failure.
      See Also:

    • topLevelAbort

      public int topLevelAbort()
      Description copied from class: AbstractRecord
      A rollback of a top-level transaction has occurred.
      Specified by:
      topLevelAbort in class AbstractRecord
      Returns:
      TwoPhaseOutcome to indicate success/failure.
      See Also:

    • topLevelCommit

      public int topLevelCommit()
      Description copied from class: AbstractRecord
      A commit of a top-level transaction has occurred.
      Specified by:
      topLevelCommit in class AbstractRecord
      Returns:
      TwoPhaseOutcome to indicate success/failure.
      See Also:

    • topLevelPrepare

      public int topLevelPrepare()
      Description copied from class: AbstractRecord
      A prepare for a top-level transaction has occurred.
      Specified by:
      topLevelPrepare in class AbstractRecord
      Returns:
      TwoPhaseOutcome to indicate success/failure.
      See Also:

    • nestedOnePhaseCommit

      public int nestedOnePhaseCommit()
      Description copied from class: AbstractRecord
      Perform a nested one phase commit.
      Overrides:
      nestedOnePhaseCommit in class AbstractRecord
      Returns:
      TwoPhaseOutcome to indicate success/failure.
      See Also:

    • topLevelOnePhaseCommit

      public int topLevelOnePhaseCommit()
      Description copied from class: AbstractRecord
      Perform a top-level one phase commit.
      Overrides:
      topLevelOnePhaseCommit in class AbstractRecord
      Returns:
      TwoPhaseOutcome to indicate success/failure.
      See Also:

    • forgetHeuristic

      public boolean forgetHeuristic()
      Description copied from class: AbstractRecord
      Forget any heuristic outcome which this implementation may have produced.
      Overrides:
      forgetHeuristic in class AbstractRecord
      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.

    • remove

      public static void remove(AbstractRecord toDelete)

    • print

      public void print(PrintWriter strm)
      Description copied from class: AbstractRecord
      Write information about this specific instance to the specified stream.
      Overrides:
      print in class AbstractRecord
      Parameters:
      strm - the stream on which to output.

    • restore_state

      public boolean restore_state(InputObjectState os, int t)
      restore_state and save_state for ResourceRecords doesn't generally apply due to object pointers. However, we need to save something so we can recover failed transactions. So, rather than insist that all Resources derive from a class which we can guarantee will give us some unique id, we simply rely on string_to_object and object_to_string to be meaningful.
      Overrides:
      restore_state in class AbstractRecord
      Returns:
      true if successful, false otherwise.

    • save_state

      public boolean save_state(OutputObjectState os, int t)
      Description copied from class: AbstractRecord
      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. If a derived class calls super.save_state then it must be called before packing any other data item.
      Overrides:
      save_state in class AbstractRecord
      Returns:
      true if successful, false otherwise.

    • type

      public String type()
      Description copied from class: AbstractRecord
      Re-implementation of abstract methods inherited from base class.
      Overrides:
      type in class AbstractRecord

    • doSave

      public boolean doSave()
      Description copied from class: AbstractRecord
      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).
      Overrides:
      doSave in class AbstractRecord
      Returns:
      true if it should be saved, false otherwise. false is the default.

    • getRCUid

      public final Uid getRCUid()

    • merge

      public void merge(AbstractRecord a)
      Description copied from class: AbstractRecord
      Merge the current record with the one presented.
      Specified by:
      merge in class AbstractRecord
      Parameters:
      a - the record with which to merge.

    • alter

      public void alter(AbstractRecord a)
      Description copied from class: AbstractRecord
      Alter the current record with the one presented.
      Specified by:
      alter in class AbstractRecord
      Parameters:
      a - the record with which to alter.

    • shouldAdd

      public boolean shouldAdd(AbstractRecord a)
      Description copied from class: AbstractRecord
      Should we add the record presented to the intentions list?
      Specified by:
      shouldAdd in class AbstractRecord
      Parameters:
      a - The record to try to add.
      Returns:
      true if the record should be added, false otherwise.

    • shouldAlter

      public boolean shouldAlter(AbstractRecord a)
      Description copied from class: AbstractRecord
      Should we alter the current record with the one presented?
      Specified by:
      shouldAlter in class AbstractRecord
      Parameters:
      a - The record to try to alter.
      Returns:
      true if the record should be altered, false otherwise.

    • shouldMerge

      public boolean shouldMerge(AbstractRecord a)
      Description copied from class: AbstractRecord
      Should we merge the current record with the one presented?
      Specified by:
      shouldMerge in class AbstractRecord
      Parameters:
      a - The record to try to merge.
      Returns:
      true if the record should be merged, false otherwise.

    • shouldReplace

      public boolean shouldReplace(AbstractRecord rec)
      Description copied from class: AbstractRecord
      Should we replace the record presented with the current record?
      Specified by:
      shouldReplace in class AbstractRecord
      Parameters:
      rec - The record to try to replace.
      Returns:
      true if the record should be replaced, false otherwise.