com.ibm.websphere.objectgrid.plugins.io
Interface ValueDataSerializer.Mergeable

All Superinterfaces:

DataSerializer, DataSerializer.DataAttributeInflatable, ValueDataSerializer

Enclosing interface:

ValueDataSerializer

public static interface ValueDataSerializer.Mergeable
extends ValueDataSerializer

ValueDataSerializers implement the optional Mergeable interface when it is possible that the clients or replicas in the grid may have multiple versions of the serializer. The Mergeable interface allows the VersionDataSerializer to merge the two serialized forms when the data is updated, to prevent data loss.

Since:

7.1.1

Nested Class Summary

static class

ValueDataSerializer.Mergeable.MergeType Used by the mergeDataObjects(DataObjectContext, XsDataInputStream, XsDataInputStream, XsDataOutputStream) method to indicate the form of the data object's merged result.

Nested classes/interfaces inherited from interface com.ibm.websphere.objectgrid.plugins.io.ValueDataSerializer

ValueDataSerializer.Mergeable, ValueDataSerializer.Versionable

Nested classes/interfaces inherited from interface com.ibm.websphere.objectgrid.plugins.io.DataSerializer

DataSerializer.DataAttributeInflatable, DataSerializer.Identifiable, DataSerializer.SpecialValue, DataSerializer.UserReadable

Method Summary

ValueDataSerializer.Mergeable.MergeType

mergeDataObjects(DataObjectContext ctx, XsDataInputStream existingDataObjectInputStream, XsDataInputStream updatedDataObjectInputStream, XsDataOutputStream mergedDataObjectOutputStream) This method is invoked when updating a cache value.

Methods inherited from interface com.ibm.websphere.objectgrid.plugins.io.ValueDataSerializer

getValueDataDescriptor

Methods inherited from interface com.ibm.websphere.objectgrid.plugins.io.DataSerializer.DataAttributeInflatable

getAttributeContexts, inflateDataObjectAttributes

Methods inherited from interface com.ibm.websphere.objectgrid.plugins.io.DataSerializer

inflateDataObject, serializeDataObject

Method Detail

mergeDataObjects

ValueDataSerializer.Mergeable.MergeType mergeDataObjects(DataObjectContext ctx,
                                                         XsDataInputStream existingDataObjectInputStream,
                                                         XsDataInputStream updatedDataObjectInputStream,
                                                         XsDataOutputStream mergedDataObjectOutputStream)
                                                         throws IOException

This method is invoked when updating a cache value. If the existing object contains data that the current DataSerializer doesn't recognize, the two data streams can be combined into the resulting merged data output stream.

Do not store or use the data streams beyond the confines of this method call. The data streams are owned by the WebSphere eXtreme Scale framework and my be closed, pooled or reused as required.

Parameters:

ctx - the context of the method call.

existingDataObjectInputStream - the data input stream to read the old object, produced from DataSerializer.serializeDataObject(DataObjectContext, Object, XsDataOutputStream) before the update. Must not be null.

updatedDataObjectInputStream - the data input stream to read the old object, produced from DataSerializer.serializeDataObject(DataObjectContext, Object, XsDataOutputStream) before the update. Must not be null.

mergedDataObjectOutputStream - the data output stream to store the merged object, compatible with that produced from DataSerializer.serializeDataObject(DataObjectContext, Object, XsDataOutputStream) for the merged object. Ignored if the return value is not ValueDataSerializer.Mergeable.MergeType.MERGE. Must not be null.

Returns:

One of the MergeType attributes representing the form of the object merge. Data in the mergedObject stream is ignored if the value is other than ValueDataSerializer.Mergeable.MergeType.MERGE

Throws:

IOException - thrown if there is a problem reading or writing the data.