Package org.multiverse.api

Interface TxnFactoryBuilder

  • All Known Subinterfaces:
    GammaTxnFactoryBuilder
    public interface TxnFactoryBuilder
    A Builder for creating a TxnFactory and TxnExecutor. This builder provides full control on transaction settings.

    Since the Txn and TxnExecutor are very closely integrated, both of them are created by this TxnFactoryBuilder.

    Instances of this class are considered immutable, so when you call one of the modifying methods, make sure that you use the resulting TxnFactoryBuilder. Normally with the builder implementation the same instance is returned. In this case this isn't true because a new instance is returned every time.

    See Also:
    TxnFactory, TxnConfig

    • Method Detail

      • getConfig

        TxnConfig getConfig()
        Returns the TxnConfig used by this TxnFactoryBuilder.
        Returns:
        the used TxnConfig.

      • setControlFlowErrorsReused

        TxnFactoryBuilder setControlFlowErrorsReused​(boolean reused)
        Sets if the ControlFlowError is reused. Normally you don't want to reuse them because they can be expensive to create (especially the stacktrace) and they could be created very often. But for debugging purposes it can be quite annoying because you want to see the stacktrace.
        Parameters:
        reused - true if ControlFlowErrors should be reused.
        Returns:
        the updated TxnFactoryBuilder.
        See Also:
        TxnConfig.isControlFlowErrorsReused()

      • setFamilyName

        TxnFactoryBuilder setFamilyName​(String familyName)
        Sets the Txn familyname. If an TxnExecutor is used inside a method, a useful familyname could be the full name of the class and the method.

        The transaction familyName is useful debugging purposes, but has not other meaning.

        Parameters:
        familyName - the familyName of the transaction.
        Returns:
        the updated TxnFactoryBuilder
        Throws:
        NullPointerException - if familyName is null.
        See Also:
        TxnConfig.getFamilyName()

      • setWriteLockMode

        TxnFactoryBuilder setWriteLockMode​(LockMode lockMode)
        Sets the Txn LockMode for all writes. For a write, always a read needs to be done, so if the read LockMode is

        Freshly constructed objects that are not committed, automatically are locked with LockMode.Exclusive.

        If the write LockMode is set after the read LockMode and the write LockMode is lower than the read LockMode, an IllegalTxnFactoryException will be thrown when a TxnFactory is created.

        If the write LockMode is set before the read LockMode and the write LockMode is lower than the read LockMode, the write LockMode automatically is upgraded to that of the read LockMode. This makes setting the readLock mode less of a nuisance.

        Parameters:
        lockMode - the LockMode to set.
        Returns:
        the updated TxnFactoryBuilder.
        Throws:
        NullPointerException - if lockMode is null.
        See Also:
        TxnConfig.getWriteLockMode(), LockMode

      • addPermanentListener

        TxnFactoryBuilder addPermanentListener​(TxnListener listener)
        Adds a permanent Txn TxnListener. All permanent listeners are always executed after all normal listeners are executed. If the same listener is added multiple times, it will be executed multiple times.

        This method is very useful for integrating Multiverse in other JVM based environments because with this approach you have a callback when transaction aborts/commit and can add your own logic. See the TxnListener for more information about normal vs permanent listeners.

        Parameters:
        listener - the permanent listener to add.
        Returns:
        the updated TxnFactoryBuilder.
        Throws:
        NullPointerException - if listener is null.
        See Also:
        TxnConfig.getPermanentListeners()

      • setTimeoutNs

        TxnFactoryBuilder setTimeoutNs​(long timeoutNs)
        Sets the timeout (the maximum time a Txn is allowed to block. Long.MAX_VALUE indicates that an unbound timeout should be used.
        Parameters:
        timeoutNs - the timeout specified in nano seconds
        Returns:
        the updated TxnFactoryBuilder
        See Also:
        TxnConfig.getTimeoutNs(), Txn.getRemainingTimeoutNs()

      • setInterruptible

        TxnFactoryBuilder setInterruptible​(boolean interruptible)
        Sets if the Txn can be interrupted while doing blocking operations.
        Parameters:
        interruptible - if the transaction can be interrupted while doing blocking operations.
        Returns:
        the updated TxnFactoryBuilder
        See Also:
        TxnConfig.isInterruptible()

      • setDirtyCheckEnabled

        TxnFactoryBuilder setDirtyCheckEnabled​(boolean dirtyCheckEnabled)
        Sets if the Txn dirty check is enabled. Dirty check is that something only needs to be written, if there really is a change (else it will be interpreted as a read). If it is disabled, it will always write, and this could prevent the aba isolation anomaly, but causes more conflicts so more contention. In most cases enabling it is the best option.
        Parameters:
        dirtyCheckEnabled - true if dirty check should be executed, false otherwise.
        Returns:
        the updated TxnFactoryBuilder.
        See Also:
        TxnConfig.isDirtyCheckEnabled()

      • setSpinCount

        TxnFactoryBuilder setSpinCount​(int spinCount)
        Sets the maximum number of spins that are allowed when a Txn can't be read/written/locked because it is locked by another transaction.

        Setting the value to a very high value, could lead to more an increased chance of a live locking.

        Parameters:
        spinCount - the maximum number of spins
        Returns:
        the updated TxnFactoryBuilder.
        Throws:
        IllegalArgumentException - if spinCount smaller than 0.
        See Also:
        TxnConfig.getSpinCount()

      • setReadonly

        TxnFactoryBuilder setReadonly​(boolean readonly)
        Sets the readonly property on a Txn. If a transaction is configured as readonly, no write operations (also no construction of new transactional objects making use of that transaction) is allowed
        Parameters:
        readonly - true if the transaction should be readonly, false otherwise.
        Returns:
        the updated TxnFactoryBuilder
        See Also:
        TxnConfig.isReadonly()

      • setReadTrackingEnabled

        TxnFactoryBuilder setReadTrackingEnabled​(boolean enabled)
        Sets if the Txn should automatically track all reads that have been done. This is needed for blocking operations, but also for other features like writeskew detection.

        Tracking reads puts more pressure on the transaction since it needs to store all reads, but it reduces the chance of read conflicts, since once read from main memory, it can be retrieved from the transaction. The transaction is free to track reads even though this property is disabled.

        Parameters:
        enabled - true if read tracking enabled, false otherwise.
        Returns:
        the updated TxnFactoryBuilder
        See Also:
        TxnConfig.isReadTrackingEnabled()

      • setSpeculative

        TxnFactoryBuilder setSpeculative​(boolean speculative)
        With the speculative configuration enabled, the Stm is allowed to determine optimal settings for a Txn.

        Some behavior like readonly or the need for tracking reads can be determined runtime. The system can start with a readonly non readtracking transaction and upgrade to an update or a read tracking once a write or retry happens.

        It depends on the Stm implementation on which properties it is going to speculate.

        Enabling it can cause a few unexpected 'retries' of transactions, but it can seriously improve performance.

        Parameters:
        speculative - indicates if speculative configuration should be enabled.
        Returns:
        the updated TxnFactoryBuilder
        See Also:
        TxnConfig.isSpeculative()

      • setMaxRetries

        TxnFactoryBuilder setMaxRetries​(int maxRetries)
        Sets the the maximum count a Txn can be retried. The default is 1000. Setting it to a very low value could mean that a transaction can't complete. Setting it to a very high value could lead to live-locking.

        If the speculative configuration mechanism is enabled (setSpeculative(boolean)), a few retries are done in the beginning to figure out the best settings.

        Parameters:
        maxRetries - the maximum number of times a transaction can be tried.
        Returns:
        the updated TxnFactoryBuilder
        Throws:
        IllegalArgumentException - if maxRetries smaller than 0.
        See Also:
        TxnConfig.getMaxRetries()

      • setBlockingAllowed

        TxnFactoryBuilder setBlockingAllowed​(boolean blockingAllowed)
        Sets if the Txn is allowed to do an explicit retry (needed for a blocking operation). One use case for disallowing it, it when the transaction is used inside an actor, and you don't want that inside the logic executed by the agent a blocking operations is done (e.g. taking an item of a blocking queue).
        Parameters:
        blockingAllowed - true if explicit retry is allowed, false otherwise.
        Returns:
        the updated TxnFactoryBuilder

      • newTransactionFactory

        TxnFactory newTransactionFactory()
        Builds a new TxnFactory.
        Returns:
        the build TxnFactory.
        Throws:
        IllegalTxnFactoryException - if the TxnFactory could not be build because the configuration was not correct.

      • newTxnExecutor

        TxnExecutor newTxnExecutor()
        Builds a new TxnExecutor optimized for executing transactions created by this TxnFactoryBuilder.
        Returns:
        the created TxnExecutor.
        Throws:
        IllegalTxnFactoryException - if the TxnFactory could not be build because the configuration was not correct.