Module org.eclipse.persistence.core
Package org.eclipse.persistence.internal.indirection

Class UnitOfWorkValueHolder<T>

    • Field Detail

      • wrappedValueHolder

        protected transient ValueHolderInterface<T> wrappedValueHolder
        The value holder in the original object.

      • mapping

        protected transient DatabaseMapping mapping
        The mapping for the attribute.

      • backupValueHolder

        protected ValueHolderInterface<T> backupValueHolder
        The value holder stored in the backup copy, should not be transient.

      • remoteUnitOfWork

        protected UnitOfWorkImpl remoteUnitOfWork
        These cannot be transient because they are required for a remote unit of work. When the remote uow is serialized to the server to be committed, these are used to reconstruct the value holder on the server. They should be null for non-remote sessions.

      • sourceObject

        protected Object sourceObject

      • relationshipSourceObject

        protected transient Object relationshipSourceObject
        This attribute is used specifically for relationship support. It mimics the sourceObject attribute which is used for RemoteValueholder

      • sourceAttributeName

        protected String sourceAttributeName

      • wrappedValueHolderRemoteID

        protected ObjID wrappedValueHolderRemoteID

    • Method Detail

      • buildBackupCloneFor

        protected abstract Object buildBackupCloneFor​(Object cloneAttributeValue)
        Backup the clone attribute value.

      • buildCloneFor

        public abstract T buildCloneFor​(Object originalAttributeValue)
        Clone the original attribute value.

      • getRemoteUnitOfWork

        protected UnitOfWorkImpl getRemoteUnitOfWork()

      • getSourceAttributeName

        protected String getSourceAttributeName()

      • getSourceObject

        protected Object getSourceObject()

      • getRelationshipSourceObject

        protected Object getRelationshipSourceObject()

      • getValueFromServerObject

        protected T getValueFromServerObject()
        This is used for a remote unit of work. If the value holder is sent back to the server uninstantiated and it needs to be instantiated, then we must find the original object and get the appropriate attribute from it.

      • instantiateImpl

        protected T instantiateImpl()
        a.k.a getValueFromWrappedValueholder. The old name is no longer correct, as query based valueholders are now sometimes triggered directly without triggering the underlying valueholder.

      • isEasilyInstantiated

        public boolean isEasilyInstantiated()
        INTERNAL: Answers if this valueholder is easy to instantiate.
        Overrides:
        isEasilyInstantiated in class DatabaseValueHolder<T>
        Returns:
        true if getValue() won't trigger a database read.

      • isPessimisticLockingValueHolder

        public boolean isPessimisticLockingValueHolder()
        INTERNAL: Answers if this valueholder is a pessimistic locking one. Such valueholders are special in that they can be triggered multiple times by different UnitsOfWork. Each time a lock query will be issued. Hence even if instantiated it may have to be instantiated again, and once instantatiated all fields can not be reset.
        Specified by:
        isPessimisticLockingValueHolder in class DatabaseValueHolder<T>

      • getWrappedValueHolderRemoteID

        public ObjID getWrappedValueHolderRemoteID()
        returns wrapped ValueHolder ObjID if available

      • isSerializedRemoteUnitOfWorkValueHolder

        public boolean isSerializedRemoteUnitOfWorkValueHolder()
        Used to determine if this is a remote uow value holder that was serialized to the server. It has no reference to its wrapper value holder, so must find its original object to be able to instantiate.
        Overrides:
        isSerializedRemoteUnitOfWorkValueHolder in class DatabaseValueHolder<T>

      • instantiate

        protected T instantiate()
        Get the value from the wrapped value holder, instantiating it if necessary, and clone it.
        Specified by:
        instantiate in class DatabaseValueHolder<T>

      • instantiateForUnitOfWorkValueHolder

        public T instantiateForUnitOfWorkValueHolder​(UnitOfWorkValueHolder<T> unitOfWorkValueHolder)
        Triggers UnitOfWork valueholders directly without triggering the wrapped valueholder (this).

        When in transaction and/or for pessimistic locking the UnitOfWorkValueHolder needs to be triggered directly without triggering the wrapped valueholder. However only the wrapped valueholder knows how to trigger the indirection, i.e. it may be a batchValueHolder, and it stores all the info like the row and the query.

        Specified by:
        instantiateForUnitOfWorkValueHolder in class DatabaseValueHolder<T>

      • releaseWrappedValueHolder

        public void releaseWrappedValueHolder​(AbstractSession targetSession)
        Releases a wrapped valueholder privately owned by a particular unit of work.

        When unit of work clones are built directly from rows no object in the shared cache points to this valueholder, so it can store the unit of work as its session. However once that UnitOfWork commits and the valueholder is merged into the shared cache, the session needs to be reset to the root session, ie. the server session.

        Overrides:
        releaseWrappedValueHolder in class DatabaseValueHolder<T>

      • resetFields

        protected void resetFields()
        Reset all the fields that are not needed after instantiation.
        Overrides:
        resetFields in class DatabaseValueHolder<T>

      • setRemoteUnitOfWork

        protected void setRemoteUnitOfWork​(UnitOfWorkImpl remoteUnitOfWork)

      • setSourceAttributeName

        protected void setSourceAttributeName​(String name)

      • setSourceObject

        protected void setSourceObject​(Object sourceObject)

      • setRelationshipSourceObject

        protected void setRelationshipSourceObject​(Object relationshipSourceObject)

      • setWrappedValueHolder

        protected void setWrappedValueHolder​(DatabaseValueHolder<T> valueHolder)