@Override
protected ViewUpdate doInBackground() {
// Get the artifact string to display from the cache. Note that one must be subtracted from the
// page index to get the corresponding artifact string index.
List<ArtifactStringContent> artifactStrings = getArtifactContentStrings();
ArtifactStringContent artifactStringContent = artifactStrings.get(pageIndex - 1);
// The getString() method of ArtifactStringContent does a lazy fetch of the attributes of the
// correspoding artifact and represents them as HTML.
String artifactString = artifactStringContent.getString();
// It may take a considerable amount of time to fetch the attributes of the selected artifact and render them
// as HTML, so check for cancellation.
if (isCancelled()) {
return null;