/// <summary>
/// Creates a IDocumentIndex instance for a specific content item id. If the content
/// item is no more published, it returns null.
/// </summary>
private IDocumentIndex ExtractDocumentIndex(ContentItem contentItem) {
// ignore deleted or unpublished items
if (contentItem == null || (!contentItem.IsPublished() && !contentItem.HasDraft())) {
return null;
}
var documentIndex = _indexProvider.New(contentItem.Id);
// call all handlers to add content to index
_contentManager.Index(contentItem, documentIndex);
return documentIndex;
}