Class MergeManager


  • public class MergeManager
    extends Object

    Purpose: Used to manage the merge of two objects in a unit of work.

    Since:
    TOPLink/Java 1.1
    Author:
    James Sutherland
    • Field Detail

      • objectDescriptors

        protected Map objectDescriptors
        Used only while refreshing objects on remote session
      • mergedNewObjects

        protected IdentityHashMap mergedNewObjects
        Used to keep track of merged new objects.
      • acquiredLocks

        protected ArrayList<CacheKey> acquiredLocks
        Used to store the list of locks that this merge manager has acquired for this merge
      • writeLockQueued

        protected Object writeLockQueued
        If this variable is not null then the mergemanager is waiting on a particular primary key
      • queueNode

        protected LinkedNode queueNode
        Stores the node that holds this mergemanager within the WriteLocksManager queue
      • mergePolicy

        protected int mergePolicy
        Policy that determines merge type (i.e. merge is used for several usages).
      • WORKING_COPY_INTO_ORIGINAL

        protected static final int WORKING_COPY_INTO_ORIGINAL
        See Also:
        Constant Field Values
      • ORIGINAL_INTO_WORKING_COPY

        protected static final int ORIGINAL_INTO_WORKING_COPY
        See Also:
        Constant Field Values
      • CLONE_INTO_WORKING_COPY

        protected static final int CLONE_INTO_WORKING_COPY
        See Also:
        Constant Field Values
      • WORKING_COPY_INTO_REMOTE

        protected static final int WORKING_COPY_INTO_REMOTE
        See Also:
        Constant Field Values
      • REFRESH_REMOTE_OBJECT

        protected static final int REFRESH_REMOTE_OBJECT
        See Also:
        Constant Field Values
      • CHANGES_INTO_DISTRIBUTED_CACHE

        protected static final int CHANGES_INTO_DISTRIBUTED_CACHE
        See Also:
        Constant Field Values
      • CLONE_WITH_REFS_INTO_WORKING_COPY

        protected static final int CLONE_WITH_REFS_INTO_WORKING_COPY
        See Also:
        Constant Field Values
      • cascadePolicy

        protected int cascadePolicy
        Policy that determines how the merge will cascade to its object's parts.
      • LOCK_ON_MERGE

        public static boolean LOCK_ON_MERGE
        Backdoor to disable merge locks.
      • systemTime

        protected long systemTime
        Stored so that all objects merged by a merge manager can have the same readTime.
      • forceCascade

        protected boolean forceCascade
        Force cascade merge even if a clone is already registered
      • isTransitionedToDeferredLocks

        protected boolean isTransitionedToDeferredLocks
        records that deferred locks have been employed for the merge process
      • lockThread

        protected Thread lockThread
        save the currentThread for later comparison to the activeThread in case they don't match
      • isForRefresh

        protected boolean isForRefresh
        records that this merge process is for a refresh
    • Method Detail

      • cascadeAllParts

        public void cascadeAllParts()
        Cascade all parts, this is the default for the merge.
      • cascadePrivateParts

        public void cascadePrivateParts()
        Cascade private parts, this can be used to merge clone when using RMI.
      • dontCascadeParts

        public void dontCascadeParts()
        Merge only direct parts, this can be used to merge clone when using RMI.
      • getCascadePolicy

        public int getCascadePolicy()
      • getMergePolicy

        protected int getMergePolicy()
      • getObjectDescriptors

        public Map getObjectDescriptors()
      • getObjectsAlreadyMerged

        public Map getObjectsAlreadyMerged()
      • getQueueNode

        public LinkedNode getQueueNode()
        INTENRAL: Used to get the node that this merge manager is stored in, within the WriteLocksManager write lockers queue
      • getSystemTime

        public long getSystemTime()
        Get the stored value of the current time. This method lazily initializes so that read times for the same merge manager can all be set to the same read time
      • getTargetVersionOfSourceObject

        public Object getTargetVersionOfSourceObject​(Object source,
                                                     ClassDescriptor descriptor,
                                                     AbstractSession targetSession)
        Return the corresponding value that should be assigned to the target object for the source object. This value must be local to the targets object space.
      • registerExistingObjectOfReadOnlyClassInNestedTransaction

        public Object registerExistingObjectOfReadOnlyClassInNestedTransaction​(Object source,
                                                                               ClassDescriptor descriptor,
                                                                               AbstractSession targetSession)
        INTERNAL: Used to register an existing object used in nested unit of work with read-only class in root unit of work.
      • getWriteLockQueued

        public Object getWriteLockQueued()
        INTENRAL: Used to get the object that the merge manager is waiting on, in order to acquire locks
      • isForRefresh

        public boolean isForRefresh()
        Returns:
        the isForMerge
      • setForRefresh

        public void setForRefresh​(boolean isforRefresh)
        Parameters:
        isforRefresh - the isForMerge to set
      • isTransitionedToDeferredLocks

        public boolean isTransitionedToDeferredLocks()
        INTERNAL: Will return if the merge process has transitioned the active merge locks to deferred locks for readlock deadlock avoidance.
      • mergeChangesForRefreshingRemoteObject

        protected Object mergeChangesForRefreshingRemoteObject​(Object serverSideDomainObject)
        Recursively merge the RMI clone from the server into the client unit of work working copy. This will only be called if the working copy exists.
      • mergeChangesFromChangeSet

        public void mergeChangesFromChangeSet​(UnitOfWorkChangeSet uowChangeSet)
        INTERNAL: Merge the changes to all objects to session's cache.
      • mergeChangesIntoDistributedCache

        protected Object mergeChangesIntoDistributedCache​(Object original,
                                                          ObjectChangeSet changeSet)
        Merge the changes specified within the changeSet into the cache. The object passed in is the original object from the cache.
      • mergeChangesOfCloneIntoWorkingCopy

        protected Object mergeChangesOfCloneIntoWorkingCopy​(Object rmiClone)
        Recursively merge to rmi clone into the unit of work working copy. The map is used to resolve recursion.
      • mergeChangesOfOriginalIntoWorkingCopy

        protected Object mergeChangesOfOriginalIntoWorkingCopy​(Object clone)
        Recursively merge to original from its parent into the clone. The map is used to resolve recursion.
      • mergeChangesOfWorkingCopyIntoOriginal

        protected Object mergeChangesOfWorkingCopyIntoOriginal​(Object clone,
                                                               ObjectChangeSet objectChangeSet)
        Recursively merge to clone into the original in its parent. The map is used to resolve recursion.
      • mergeChangesOfWorkingCopyIntoOriginal

        protected CacheKey mergeChangesOfWorkingCopyIntoOriginal​(Object clone,
                                                                 ObjectChangeSet objectChangeSet,
                                                                 ClassDescriptor descriptor,
                                                                 AbstractSession targetSession,
                                                                 UnitOfWorkImpl unitOfWork)
        Recursively merge to clone into the original in its parent. The map is used to resolve recursion. This is used to merge objects from the unit of work into the shared (or isolated) cache.
      • mergeChangesOfWorkingCopyIntoRemote

        public Object mergeChangesOfWorkingCopyIntoRemote​(Object clone)
                                                   throws ValidationException
        Recursively merge changes in the object dependent on the merge policy. This merges changes from a remote unit of work back from the server into the original remote unit of work. This is meant to merge server-side changes such as sequence numbers, version numbers or events triggered changes.
        Throws:
        ValidationException
      • mergeCloneIntoWorkingCopy

        public void mergeCloneIntoWorkingCopy()
        This can be used by the user for merging clones from RMI into the unit of work.
      • mergeCloneWithReferencesIntoWorkingCopy

        public void mergeCloneWithReferencesIntoWorkingCopy()
        This is used during the merge of dependent objects referencing independent objects, where you want the independent objects merged as well.
      • mergeIntoDistributedCache

        public void mergeIntoDistributedCache()
        This is used during cache synchronization to merge the changes into the distributed cache.
      • mergeNewObjectIntoCache

        public Object mergeNewObjectIntoCache​(ObjectChangeSet changeSet)
        Merge a change set for a new object into the cache. This method will create a shell for the new object and then merge the changes from the change set into the object. The newly merged object will then be added to the cache.
      • mergeOriginalIntoWorkingCopy

        public void mergeOriginalIntoWorkingCopy()
        This is used to revert changes to objects, or during refreshes.
      • mergeWorkingCopyIntoOriginal

        public void mergeWorkingCopyIntoOriginal()
        This is used during the unit of work commit to merge changes into the parent.
      • mergeWorkingCopyIntoRemote

        public void mergeWorkingCopyIntoRemote()
        This is used during the unit of work commit to merge changes into the parent.
      • refreshRemoteObject

        public void refreshRemoteObject()
        INTERNAL: This is used to refresh remote session object
      • registerObjectForMergeCloneIntoWorkingCopy

        protected Object registerObjectForMergeCloneIntoWorkingCopy​(Object clone,
                                                                    boolean shouldForceCascade)
        INTERNAL: When merging from a clone when the cache cannot be guaranteed the object must be first read if it is existing and not in the cache. Otherwise no changes will be detected as the original state is missing.
      • checkNewObjectLockVersion

        public void checkNewObjectLockVersion​(Object clone,
                                              Object primaryKey,
                                              ClassDescriptor descriptor,
                                              UnitOfWorkImpl unitOfWork)
        Check if the new object's version has been set, if so, then it was an existing object that was deleted. Raise an error instead of reincarnating the object.
      • registerRemovedNewObjectIfRequired

        public void registerRemovedNewObjectIfRequired​(Object removedObject)
        Determine if the object is a registered new object, and that this is a nested unit of work merge into the parent. In this case private mappings will register the object as being removed.
      • setCascadePolicy

        public void setCascadePolicy​(int cascadePolicy)
      • setMergePolicy

        protected void setMergePolicy​(int mergePolicy)
      • setForceCascade

        public void setForceCascade​(boolean forceCascade)
      • setObjectDescriptors

        public void setObjectDescriptors​(Map objectDescriptors)
      • setObjectsAlreadyMerged

        protected void setObjectsAlreadyMerged​(Map objectsAlreadyMerged)
      • setQueueNode

        public void setQueueNode​(LinkedNode node)
        INTENRAL: Used to set the node that this merge manager is stored in, within the WriteLocksManager write lockers queue
      • setWriteLockQueued

        public void setWriteLockQueued​(Object primaryKey)
        INTENRAL: Used to set the object that the merge manager is waiting on, in order to acquire locks If this value is null then the merge manager is not waiting on any locks.
      • shouldCascadeByMapping

        public boolean shouldCascadeByMapping()
        Flag used to determine that the mappings should be checked for cascade requirements.
      • shouldCascadeAllParts

        public boolean shouldCascadeAllParts()
        Flag used to determine if all parts should be cascaded
      • shouldCascadeParts

        public boolean shouldCascadeParts()
        Flag used to determine if any parts should be cascaded
      • shouldCascadePrivateParts

        public boolean shouldCascadePrivateParts()
        Flag used to determine if any private parts should be cascaded
      • shouldCascadeReferences

        public boolean shouldCascadeReferences()
        Refreshes are based on the objects row, so all attributes of the object must be refreshed. However merging from RMI, normally reference are made transient, so should not be merge unless specified.
      • shouldMergeChangesIntoDistributedCache

        public boolean shouldMergeChangesIntoDistributedCache()
        INTERNAL: This happens when changes from an UnitOfWork is propagated to a distributed class.
      • shouldMergeCloneIntoWorkingCopy

        public boolean shouldMergeCloneIntoWorkingCopy()
        This can be used by the user for merging clones from RMI into the unit of work.
      • shouldMergeCloneWithReferencesIntoWorkingCopy

        public boolean shouldMergeCloneWithReferencesIntoWorkingCopy()
        This can be used by the user for merging remote EJB objects into the unit of work.
      • shouldMergeOriginalIntoWorkingCopy

        public boolean shouldMergeOriginalIntoWorkingCopy()
        This is used to revert changes to objects, or during refreshes.
      • shouldMergeWorkingCopyIntoOriginal

        public boolean shouldMergeWorkingCopyIntoOriginal()
        This is used during the unit of work commit to merge changes into the parent.
      • shouldMergeWorkingCopyIntoRemote

        public boolean shouldMergeWorkingCopyIntoRemote()
        INTERNAL: This happens when serialized remote unit of work has to be merged with local remote unit of work.
      • shouldRefreshRemoteObject

        public boolean shouldRefreshRemoteObject()
        INTERNAL: This is used to refresh objects on the remote session
      • shouldForceCascade

        public boolean shouldForceCascade()
        This is used to cascade merge even if a clone is already registered.
      • getMergedNewObjects

        public IdentityHashMap getMergedNewObjects()
        INTERNAL: Used to return a map containing new objects found through the registerObjectForMergeCloneIntoWorkingCopy method.
        Returns:
        Map
      • transitionToDeferredLocks

        public void transitionToDeferredLocks()
        INTERNAL: Records that this merge manager has transitioned to use deferred locks during the merge.
      • updateCacheKeyProperties

        protected void updateCacheKeyProperties​(UnitOfWorkImpl unitOfWork,
                                                CacheKey cacheKey,
                                                Object original,
                                                Object clone,
                                                ObjectChangeSet objectChangeSet,
                                                ClassDescriptor descriptor)
        INTERNAL: Update CacheKey properties with new information. This method is called if this code actually merges
      • getLockThread

        public Thread getLockThread()
        INTERNAL:
        Returns:
        lockThread
      • setLockThread

        public void setLockThread​(Thread lockThread)
        INTERNAL: Save the currentThread for later comparison to the activeThread in case they don't match
        Parameters:
        lockThread -