this.db = db;
this.query = query;
if (!(query instanceof SelectQuery)) {
throw new QueryException("Only select queries are supported.");
}
SelectQuery select = (SelectQuery)query;
Set<String> returnVars = select.getReturnVariables();
if (returnVars.size()!=1) {
throw new QueryException("Only one entry/feed return variable is currently supported.");
}
var = returnVars.iterator().next();
List<Triple> triples = select.getWhereClause().getClauses();
pivot = null;
entryPivot = false;
feedPivot = false;
unsatisfiable = false;
Triple lastBind = null;