KnowledgeSyncProvider.ProcessChangeBatch Method

When overridden in a derived class, processes a set of changes by detecting conflicts and applying changes to the item store.

Namespace: Microsoft.Synchronization
Assembly: Microsoft.Synchronization (in microsoft.synchronization.dll)

Syntax

'Declaration
Public MustOverride Sub ProcessChangeBatch ( _
    resolutionPolicy As ConflictResolutionPolicy, _
    sourceChanges As ChangeBatch, _
    changeDataRetriever As Object, _
    syncCallbacks As SyncCallbacks, _
    sessionStatistics As SyncSessionStatistics _
)
'Usage
Dim instance As KnowledgeSyncProvider
Dim resolutionPolicy As ConflictResolutionPolicy
Dim sourceChanges As ChangeBatch
Dim changeDataRetriever As Object
Dim syncCallbacks As SyncCallbacks
Dim sessionStatistics As SyncSessionStatistics

instance.ProcessChangeBatch(resolutionPolicy, sourceChanges, changeDataRetriever, syncCallbacks, sessionStatistics)

public abstract void ProcessChangeBatch (
    ConflictResolutionPolicy resolutionPolicy,
    ChangeBatch sourceChanges,
    Object changeDataRetriever,
    SyncCallbacks syncCallbacks,
    SyncSessionStatistics sessionStatistics
)

public:
virtual void ProcessChangeBatch (
    ConflictResolutionPolicy resolutionPolicy, 
    ChangeBatch^ sourceChanges, 
    Object^ changeDataRetriever, 
    SyncCallbacks^ syncCallbacks, 
    SyncSessionStatistics^ sessionStatistics
) abstract

public abstract void ProcessChangeBatch (
    ConflictResolutionPolicy resolutionPolicy, 
    ChangeBatch sourceChanges, 
    Object changeDataRetriever, 
    SyncCallbacks syncCallbacks, 
    SyncSessionStatistics sessionStatistics
)

public abstract function ProcessChangeBatch (
    resolutionPolicy : ConflictResolutionPolicy, 
    sourceChanges : ChangeBatch, 
    changeDataRetriever : Object, 
    syncCallbacks : SyncCallbacks, 
    sessionStatistics : SyncSessionStatistics
)

Parameters

• resolutionPolicy
  The conflict resolution policy to use when this method applies changes.

• sourceChanges
  A batch of changes from the source provider to be applied locally.

• changeDataRetriever
  An object that can be used to retrieve change data. It can be an IChangeDataRetriever object or a provider-specific object.

• syncCallbacks
  An object that receives event notifications during change application.

• sessionStatistics
  Tracks change statistics. For a provider that uses custom change application, this object must be updated with the results of the change application.

Remarks

When a source change contains change unit changes, the destination provider must determine which, if any, change unit versions to include in the batch of destination versions that is sent to the change applier. This decision depends on the type of change from the source provider and whether the item is marked as deleted on the destination replica. For more information, see Synchronizing Change Units.

Example

The following example gets the destination version of all items in the change batch, and creates a NotifyingChangeApplier object and uses it to handle conflict detection and change application.

public override void ProcessChangeBatch(ConflictResolutionPolicy resolutionPolicy, ChangeBatch sourceChanges, object changeDataRetriever, SyncCallbacks syncCallbacks, SyncSessionStatistics sessionStatistics)
{
    // Use the metadata store to get the local versions of changes received from the source provider.
    IEnumerable<ItemChange> destVersions = _itemStore.ContactReplicaMetadata.GetLocalVersions(sourceChanges);

    // Use a NotifyingChangeApplier object to process the changes. Note that this object is passed as the INotifyingChangeApplierTarget
    // object that will be called to apply changes to the item store.
    NotifyingChangeApplier changeApplier = new NotifyingChangeApplier(IdFormats);
    changeApplier.ApplyChanges(resolutionPolicy, sourceChanges, (IChangeDataRetriever)changeDataRetriever, destVersions,
        _itemStore.ContactReplicaMetadata.GetKnowledge(), _itemStore.ContactReplicaMetadata.GetForgottenKnowledge(), 
        this, _sessionContext, syncCallbacks);
}

The following example shows the GetLocalVersions method that is called in the previous example. This example enumerates the changes in the source change batch and creates a list of destination versions.

public override IEnumerable<ItemChange> GetLocalVersions(ChangeBatch sourceChanges)
{
    List<ItemChange> localVersions = new List<ItemChange>();

    // Enumerate the source changes and retrieve the destination version for each source change. 
    foreach (ItemChange srcItem in sourceChanges)
    {
        ItemChange localVer;

        // When the source item exists in the destination metadata store, retrieve the destination version of the item.
        if (_items.ContainsKey(srcItem.ItemId))
        {
            XmlItemMetadata localMeta = _items[srcItem.ItemId];
            ChangeKind kind = (localMeta.IsDeleted) ? ChangeKind.Deleted : ChangeKind.Update;
            localVer = new ItemChange(IdFormats, ReplicaId, srcItem.ItemId, kind, localMeta.CreationVersion, localMeta.ChangeVersion);
        }
        // When the source item does not exist in the destination metadata store, create a new change with unknown
        // version information.
        else
        {
            localVer = new ItemChange(IdFormats, ReplicaId, srcItem.ItemId, ChangeKind.UnknownItem, SyncVersion.UnknownVersion, SyncVersion.UnknownVersion);
        }

        localVersions.Add(localVer);
    }

    return localVersions;
}

See Also

Reference

KnowledgeSyncProvider Class
KnowledgeSyncProvider Members
Microsoft.Synchronization Namespace