I have tried doing this via custom SearchComponent, where I can find all similar documents for each document in current search result, then add a new field into document hoping to use sort parameter (q=*&sort=similarityCount).
I don't understand this part very well, but:
But this will not work because sort is done before handling my custom search component, if added via last-components. Can't add it via first-components, because then I will have no access to query results. And I do not want to override QueryComponent because I need to have all the functionality it covers: grouping, facets, etc.
You may want to put your custom SearchComponent to last-component and inject SortSpec in your prepare() so that QueryComponent can sort the result complying with your SortSpec? koji -- http://soleami.com/blog/automatically-acquiring-synonym-knowledge-from-wikipedia.html
