Package one.microstream.persistence.types

Interface Storer

    • Method Summary

      Modifier and Type Method Description
      void clear()
      Clears all internal state regarding collected data and/or registered skips.
      Object commit()
      Ends the data collection process and causes all collected data to be persisted.
      long currentCapacity()
      Returns the internal state's value significant for its capacity of unique instances.
      Storer ensureCapacity​(long desiredCapacity)
      Ensures that the instance's internal state is prepared for handling an amount of unique instance equal to the passed value.
      Storer initialize()
      Ensures the storer instance is initialized, i.e.
      Storer initialize​(long initialCapacity)
      Ensures the storer instance is initialized, i.e.
      default boolean isEmpty()
      Queries, whether this Storer instance has no instances / references registered.
      boolean isInitialized()
      Returns whether this Storer instance has been initialized.
      long maximumCapacity()
      The maximum value that currentCapacity() can reach.
      Storer reinitialize()
      Enforces the instance to be initialized, discarding any previous state (clearing it) if necessary prior to calling initialize().
      Storer reinitialize​(long initialCapacity)
      Enforces the instance to be initialized, discarding any previous state (clearing it) if necessary prior to calling initialize().
      long size()  
      boolean skip​(Object instance)
      Registers the passed instance to be skipped from the data persisting process.
      boolean skipMapped​(Object instance, long objectId)
      Registers the passed instance under the passed objectId without persisting its data.
      boolean skipNulled​(Object instance)
      Registers the passed instance to be skipped from the data persisting process.

    • Method Detail

      • commit

        Object commit()
        Ends the data collection process and causes all collected data to be persisted.

        This is an atomatic all-or-nothing operation: either all collected data will be persisted successfully, or non of it will be persisted. Partially persisted data will be reverted / rolled back in case of a failure.

        Returns:
        some kind of status information, potentially null.

      • clear

        void clear()
        Clears all internal state regarding collected data and/or registered skips.

      • skipMapped

        boolean skipMapped​(Object instance,
                   long objectId)
        Registers the passed instance under the passed objectId without persisting its data.

        This skip means that if the passed instance is encountered while collecting data to be persisted, its data will NOT be collected. References to the passed instance will be persisted as the passed objectId.

        Warning:
        This method can be very useful to rearrange object graphs on the persistence level, but it can also cause inconsistencies if not used perfectly correctly.
        It is strongly advised to use one of the following alternatives instead: skip(Object)skipNulled(Object)

        Parameters:
        instance - the instance / reference to be skipped.
        objectId - the objectId to be used as a reference to the skipped instance.
        Returns:
        true if the instance has been newly registered, false if it already was.
        See Also:
        skip(Object), skipNulled(Object)

      • skip

        boolean skip​(Object instance)
        Registers the passed instance to be skipped from the data persisting process.

        This skip means that if the passed instance is encountered while collecting data to be persisted, its data will NOT be collected. If the instance is already registered under a certain object id at the used PersistenceObjectRegistry, then is associated object id will be used. Otherwise, the null-Id will be used, effectively "nulling out" all references to this instance on the persistent level.
        The latter behavior is exactly the same as skipNulled(Object).

        Parameters:
        instance - the instance / reference to be skipped.
        Returns:
        true if the instance has been newly registered, false if it already was.
        See Also:
        skipNulled(Object), skipMapped(Object,long)

      • skipNulled

        boolean skipNulled​(Object instance)
        Registers the passed instance to be skipped from the data persisting process.

        This skip means that if the passed instance is encountered while collecting data to be persisted, its data will NOT be collected. References to this instance will always be persisted as null, no matter if the instance is already registered for a certain object id at the used PersistenceObjectRegistryor not.
        To make the skipping consider existing object id registrations, use skip(Object).

        Parameters:
        instance - the instance / reference to be skipped by using .
        Returns:
        true if the instance has been newly registered, false if it already was.
        See Also:
        skip(Object), skipMapped(Object,long)

      • size

        long size()
        Returns:
        the amount of unique instances / references that have already been registered by thisStorer instance. This includes both instances encountered during the data collection process and instances that have explicitely been registered to be skipped.
        See Also:
        skip(Object), skipMapped(Object,long)

      • isEmpty

        default boolean isEmpty()
        Queries, whether this Storer instance has no instances / references registered.

        Calling this method is simply an alias for this.size() == 0L.

        Returns:
        whether this Storer instance is empty.

      • currentCapacity

        long currentCapacity()
        Returns the internal state's value significant for its capacity of unique instances. Note that the exact meaning of this value is implementation dependant, e.g. it might just be a hash table's length, while the actual amount of unique instances that can be handled by that hash table might be much higher (infinite).
        Returns:
        the current implementation-specific "capacity" value.

      • maximumCapacity

        long maximumCapacity()
        The maximum value that currentCapacity() can reach. For more explanation on the exact meaning of the capacity, see there.
        Returns:
        the maximum of the implementation-specific "capacity" value.

      • isInitialized

        boolean isInitialized()
        Returns whether this Storer instance has been initialized.

        That being initialized means exactely depends on the implementation. The general contract means to bring the instance's internal data into a state with which the instance can be used to perform its actual tasks.

        Returns:
        whether this Storer instance has been initialized.

      • initialize

        Storer initialize()
        Ensures the storer instance is initialized, i.e. ready to perform storing. This method is idempotent. For a forced (re)initialization, see reinitialize().
        Returns:
        this.

      • initialize

        Storer initialize​(long initialCapacity)
        Ensures the storer instance is initialized, i.e. ready to perform storing. If the storer instance needs to be initialized as a consequence of this call, the passed initialCapacityis considered as an estimate for the number of unique instances to be handled until the next commit. This method is idempotent, meaning if this instance is already initialized, the passed value might not have any effect. For a forced (re)initialization, see reinitialize(long).
        Returns:
        this.

      • reinitialize

        Storer reinitialize()
        Enforces the instance to be initialized, discarding any previous state (clearing it) if necessary prior to calling initialize().
        Returns:
        this.

      • reinitialize

        Storer reinitialize​(long initialCapacity)
        Enforces the instance to be initialized, discarding any previous state (clearing it) if necessary prior to calling initialize().
        Returns:
        this.

      • ensureCapacity

        Storer ensureCapacity​(long desiredCapacity)
        Ensures that the instance's internal state is prepared for handling an amount of unique instance equal to the passed value. Note that is explicitly does not have to mean that the instance's internal state actually reserves as much space, only makes a best effort to prepare for that amount. Example: an internal hash table's hash length might still remain at 2^30, despite the passed value being much higher.
        Parameters:
        desiredCapacity - the amount of unique instances that this instance shall prepare to handle.
        Returns:
        this