if (op instanceof RemoveParticipant) {
ParticipantId participantId = ((RemoveParticipant) op).getParticipantId();
return new CoreRemoveParticipant(participantId);
} else if (op instanceof AddParticipant) {
ParticipantId participantId = ((AddParticipant) op).getParticipantId();
return new CoreAddParticipant(participantId);
} else if (op instanceof WaveletBlipOperation) {
WaveletBlipOperation waveletBlipOp = (WaveletBlipOperation) op;
BlipOperation blipOp = waveletBlipOp.getBlipOp();
if (blipOp instanceof BlipContentOperation) {
DocOp contentOp = ((BlipContentOperation) blipOp).getContentOp();