Package org.apache.accumulo.core.fate

Interface ReadOnlyTStore<T>

  • All Known Subinterfaces:
    TStore<T>
    All Known Implementing Classes:
    AgeOffStore, ZooStore
    public interface ReadOnlyTStore<T>
    Read only access to a Transaction Store. A transaction consists of a number of operations. Instances of this class may check on the queue of outstanding transactions but may neither modify them nor create new ones.

    • Method Detail

      • reserve

        long reserve()
        Reserve a transaction that is IN_PROGRESS or FAILED_IN_PROGRESS. Reserving a transaction id ensures that nothing else in-process interacting via the same instance will be operating on that transaction id.
        Returns:
        a transaction id that is safe to interact with, chosen by the store.

      • reserve

        void reserve​(long tid)
        Reserve the specific tid. Reserving a transaction id ensures that nothing else in-process interacting via the same instance will be operating on that transaction id.

      • unreserve

        void unreserve​(long tid,
               long deferTime)
        Return the given transaction to the store. upon successful return the store now controls the referenced transaction id. caller should no longer interact with it.
        Parameters:
        tid - transaction id, previously reserved.
        deferTime - time in millis to keep this transaction out of the pool used in the reserve method. must be non-negative.

      • top

        ReadOnlyRepo<T> top​(long tid)
        Get the current operation for the given transaction id. Caller must have already reserved tid.
        Parameters:
        tid - transaction id, previously reserved.
        Returns:
        a read-only view of the operation

      • getStack

        List<ReadOnlyRepo<T>> getStack​(long tid)
        Get all operations on a transactions stack. Element 0 contains the most recent operation pushed or the top.

      • getStatus

        ReadOnlyTStore.TStatus getStatus​(long tid)
        Get the state of a given transaction. Caller must have already reserved tid.
        Parameters:
        tid - transaction id, previously reserved.
        Returns:
        execution status

      • waitForStatusChange

        ReadOnlyTStore.TStatus waitForStatusChange​(long tid,
                                           EnumSet<ReadOnlyTStore.TStatus> expected)
        Wait for the status of a transaction to change
        Parameters:
        tid - transaction id, need not have been reserved.
        expected - a set of possible statuses we are interested in being notified about. may not be null.
        Returns:
        execution status.

      • getTransactionInfo

        Serializable getTransactionInfo​(long tid,
                                Fate.TxInfo txInfo)
        Retrieve transaction-specific information. Caller must have already reserved tid.
        Parameters:
        tid - transaction id, previously reserved.
        txInfo - name of attribute of a transaction to retrieve.

      • list

        List<Long> list()
        list all transaction ids in store.
        Returns:
        all outstanding transactions, including those reserved by others.

      • timeCreated

        long timeCreated​(long tid)
        Retrieve the creation time of a FaTE transaction.
        Parameters:
        tid - Transaction id, previously reserved.
        Returns:
        creation time of transaction.