private ServerErrorCode updateBlobMap(UndeleteRequest undeleteRequest) {
    ServerErrorCode errorCode = ServerErrorCode.NoError;
    StoredBlob blob = blobs.get(undeleteRequest.getBlobId().getID());
    if (blob == null) {
      errorCode = ServerErrorCode.BlobNotFound;
    } else if (blob.isUndeleted()) {
      errorCode = ServerErrorCode.BlobAlreadyUndeleted;
    } else if (!blob.isDeleted()) {
      errorCode = ServerErrorCode.BlobNotDeleted;
    } else if (blob.hasExpired()) {
      errorCode = ServerErrorCode.BlobExpired;
    } else {
      blob.updateLifeVersion();
    }
    return errorCode;
  }
Updates the blob map based on the {@code undeleteRequest}.
@param undeleteRequest the {@link TtlUpdateRequest} that needs to be processed
ambry-router/src/test/java/com/github/ambry/router/MockServer.java