Package com.arjuna.ats.arjuna.coordinator

Class AbstractRecord

  • public abstract class AbstractRecord
extends StateManager
    Abstract Record Class This class provides an abstract template that defines the interface that the atomic action system uses to notify objects that various state transitions have occurred as the 2PC protocol executes. Record types derived from this class manage certain properties of objects such as recovery information, concurrency control information etc, and all must redefine the operations defined here as abstract to take appropriate action. Many functions are declared pure virtual to force a definition to occur in any derived class. These are currently all functions dealing with atomic action coordination as well as the following list management functions: typeIs: returns the record type of the instance. This is one of the values of the enumerated type Record_type value: Some arbitrary value associated with the record instance merge: Used when two records need to merge together. Currently this is only used by CadaverRecords to merge information from PersistenceRecords shouldAdd: returns TRUE is the record should be added to the list FALSE if it should be discarded shouldMerge: returns TRUE is the two records should be merged into a single record, FALSE if it should be discarded shouldReplace: returns TRUE if the record should replace an existing one, FALSE otherwise.
    Since:
    1.0.
    Version:
    $Id: AbstractRecord.java 2342 2006-03-30 13:06:17Z $
    Author:
    Mark Little (mark@arjuna.com)

    • Constructor Detail

      • AbstractRecord

        protected AbstractRecord​(Uid storeUid,
                         String objType,
                         int otype)
        Create a new instance with the specified parameters.
        Parameters:
        storeUid - the unique id for this instance.
        objType - the type of the instance.
        otype - the ObjectType of the object.
        See Also:
        ObjectType

      • AbstractRecord

        protected AbstractRecord​(Uid storeUid)
        Create a new instance with the specified paramaters.
        Parameters:
        storeUid - the unique id for this instance.

      • AbstractRecord

        public AbstractRecord()
        Creates a 'blank' abstract record. This is used during crash recovery when recreating the prepared list of a server atomic action.

    • Method Detail

      • typeIs

        public abstract int typeIs()
        Returns:
        RecordType value.

      • value

        public abstract Object value()
        If this abstract record caused a heuristic then it should return an object which implements HeuristicInformation
        Returns:
        Object to be used to order.

      • setValue

        public abstract void setValue​(Object o)

      • nestedAbort

        public abstract int nestedAbort()
        A rollback of a nested transaction has occurred.
        Returns:
        TwoPhaseOutcome to indicate success/failure.
        See Also:
        TwoPhaseOutcome

      • nestedCommit

        public abstract int nestedCommit()
        A commit of a nested transaction has occurred.
        Returns:
        TwoPhaseOutcome to indicate success/failure.
        See Also:
        TwoPhaseOutcome

      • nestedPrepare

        public abstract int nestedPrepare()
        A prepare for a nested transaction has occurred.
        Returns:
        TwoPhaseOutcome to indicate success/failure.
        See Also:
        TwoPhaseOutcome

      • topLevelAbort

        public abstract int topLevelAbort()
        A rollback of a top-level transaction has occurred.
        Returns:
        TwoPhaseOutcome to indicate success/failure.
        See Also:
        TwoPhaseOutcome

      • topLevelCommit

        public abstract int topLevelCommit()
        A commit of a top-level transaction has occurred.
        Returns:
        TwoPhaseOutcome to indicate success/failure.
        See Also:
        TwoPhaseOutcome

      • topLevelPrepare

        public abstract int topLevelPrepare()
        A prepare for a top-level transaction has occurred.
        Returns:
        TwoPhaseOutcome to indicate success/failure.
        See Also:
        TwoPhaseOutcome

      • order

        public Uid order()
        Return the Uid of this abstract record so that it can be ordered in the intentions list. This is also the Uid that the record was saved with in the object store.
        Returns:
        Uid for this instance.
        See Also:
        Uid

      • getTypeOfObject

        public String getTypeOfObject()
        Return the type of the abstract record. Used in ordering the instances in the intentions list. This is also the type that the record was saved with in the object store.
        Returns:
        String representing type.

      • propagateOnAbort

        public boolean propagateOnAbort()
        Determine if records are discarded on action abort or must be propagated to parents.
        Returns:
        true if the record should be propagated to the parent transaction if the current transaction rolls back, false otherwise. The default is false.

      • propagateOnCommit

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

      • equals

        public final boolean equals​(AbstractRecord ar)
        Determine if two records are equal in that both are the same type and have the same order value (determined via 'order()').
        Returns:
        true if equal, false otherwise.

      • lessThan

        public final boolean lessThan​(AbstractRecord ar)
        Determine if two records are less than in that both are the same type and their Uids are less than.
        Returns:
        true if equal, false otherwise.

      • greaterThan

        public final boolean greaterThan​(AbstractRecord ar)
        Determine if two records are greater than in that both are the same type and their Uids are greater than.
        Returns:
        true if equal, false otherwise.

      • topLevelCleanup

        public int topLevelCleanup()
        Cleanup is called if a top-level action is detected to be an orphan. NOTE nested actions are never orphans since their parents would be aborted we may as well abort them as well.
        Returns:
        TwoPhaseOutcome as default is the same as topLevelAbort.

      • nestedCleanup

        public int nestedCleanup()
        Cleanup is called if a nested is detected to be an orphan. NOTE nested actions are never orphans since their parents would be aborted we may as well abort them as well.
        Returns:
        TwoPhaseOutcome as default is the same as nestedAbort.

      • doSave

        public boolean doSave()
        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).
        Returns:
        true if it should be saved, false otherwise. false is the default.

      • type

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

      • print

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

      • save_state

        public boolean save_state​(OutputObjectState os,
                          int i)
        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 StateManager
        Returns:
        true if successful, false otherwise.

      • restore_state

        public boolean restore_state​(InputObjectState os,
                             int i)
        During recovery, the transaction log is given to the recovery system and it will recreate a transaction instance to perform necessary recovery actions. This transaction will recreate the intentions list and give each recreated AbstractRecord the state that that was saved during transaction persistence. The base class will restore information that it needs from the log. Data items must be unpacked in the same order that they were packed.
        Overrides:
        restore_state in class StateManager
        Returns:
        true if successful, false otherwise.

      • forgetHeuristic

        public boolean forgetHeuristic()
        Forget any heuristic outcome which this implementation may have produced.
        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.

      • clearHeuristicDecision

        public void clearHeuristicDecision()
        Clearing the heuristic state on the resource. If the resource maintains a state of the prior heuristic outcome then it should use this method to clear the state and forget the heuristic.

      • nestedOnePhaseCommit

        public int nestedOnePhaseCommit()
        Perform a nested one phase commit.
        Returns:
        TwoPhaseOutcome to indicate success/failure.
        See Also:
        TwoPhaseOutcome

      • isPermittedTopLevelOnePhaseCommit

        public boolean isPermittedTopLevelOnePhaseCommit()

        Defines if the participant record permits the use of the one phase commit optimization.

        By default it's expected this to be true but the children records can override this if it's necessary for them to forbid 1PC to be run.

        Returns:
        true if 1PC could be run for the participant, otherwise false

      • topLevelOnePhaseCommit

        public int topLevelOnePhaseCommit()
        Perform a top-level one phase commit.
        Returns:
        TwoPhaseOutcome to indicate success/failure.
        See Also:
        TwoPhaseOutcome

      • merge

        public abstract void merge​(AbstractRecord a)
        Merge the current record with the one presented.
        Parameters:
        a - the record with which to merge.

      • alter

        public abstract void alter​(AbstractRecord a)
        Alter the current record with the one presented.
        Parameters:
        a - the record with which to alter.

      • shouldAdd

        public abstract boolean shouldAdd​(AbstractRecord a)
        Should we add the record presented to the intentions list?
        Parameters:
        a - The record to try to add.
        Returns:
        true if the record should be added, false otherwise.

      • shouldAlter

        public abstract boolean shouldAlter​(AbstractRecord a)
        Should we alter the current record with the one presented?
        Parameters:
        a - The record to try to alter.
        Returns:
        true if the record should be altered, false otherwise.

      • shouldMerge

        public abstract boolean shouldMerge​(AbstractRecord a)
        Should we merge the current record with the one presented?
        Parameters:
        a - The record to try to merge.
        Returns:
        true if the record should be merged, false otherwise.

      • shouldReplace

        public abstract boolean shouldReplace​(AbstractRecord a)
        Should we replace the record presented with the current record?
        Parameters:
        a - The record to try to replace.
        Returns:
        true if the record should be replaced, false otherwise.

      • replace

        public void replace​(AbstractRecord a)
        The current record is about to replace the one presented. This method is invoked to give the current record a chance to copy information, for example, from the record being replaced.
        Parameters:
        a - the record that will replace this instance.

      • getPrevious

        protected final AbstractRecord getPrevious()
        These few functions are link manipulation primitives used by the RecordList processing software to chain instances together.
        Returns:
        the previous element in the intentions list, or null.

      • getNext

        protected final AbstractRecord getNext()
        Returns:
        the next element in the intentions list, or null.

      • setPrevious

        protected final void setPrevious​(AbstractRecord ar)
        Set the previous element in the list to the specified instance.
        Parameters:
        ar - the instance to become previous.

      • setNext

        protected final void setNext​(AbstractRecord ar)
        Set the next element in the list to the specified instance.
        Parameters:
        ar - the instance to become next.