anchor.diff:  
   The LuceneSail is a stacked Sail: To use it, simply wrap your base SAIL with it:
   
  +[source,java]
  +----
   	Sail baseSail = new NativeStore(new File("."));
       LuceneSail lucenesail = new LuceneSail();
       // set any parameters
  
positive.code:     ...
      // wrap base sail
      lucenesail.setBaseSail(baseSail);
  
  === Full text search
  
  Search is case-insensitive, wildcards and other modifiers can be used to broaden the search.
  For example, search all literals containing words starting with "alic" (e.g. persons named "Alice"):
  	
  	Repository repo = new SailRepository(lucenesail);
  	repo.initialize();
  	 
  	String qry = 
  		"PREFIX search: <http://www.openrdf.org/contrib/lucenesail#> " +
  		"SELECT ?subj ?text " +
  		"WHERE { ?subj search:matches [" +
  						" search:query ?term ; " +
  						" search:snippet ?text ] } ";
  	
  	List<BindingSet> results;	
  	try (RepositoryConnection con = repo.getConnection()) {
  		ValueFactory fac = con.getValueFactory();
  
negative.code: 	
  		results = QueryResults.asList(tq.evaluate());
  	}
  
  	results.forEach(res -> { 
  			System.out.println(res.getValue("subj").stringValue()); 
  			System.out.println(res.getValue("text").stringValue());
  	});
  ---	
  
  === SearchIndex implementations
  
  