@Override
protected ResultObjectProvider executeQuery(
Executor ex,
ClassMetaData base,
ClassMetaData[] types,
boolean subclasses,
ExpressionFactory[] facts,
QueryExpressions[] parsed,
Object[] params,
Range range) {
log.debug("In executeQuery");
IndexExpressionVisitor visitor =
new IndexExpressionVisitor((CassandraClassMetaData) base, params);
parsed[0].filter.acceptVisit(visitor);
// the list of queries we need to execute
List<IndexQuery> queries = visitor.getVisitors();
AbstractIndexOperation indexOp =
getIndexOp(
queries.get(0), parsed[0].ordering, parsed[0].ascending, (CassandraClassMetaData) base);
ResultCompiler compiler = new ResultCompiler(indexOp.getComprator());
Keyspace keyspace = conf.getKeyspace();
compiler.addScanIterator(indexOp.scanIndex(queries.get(0), keyspace));
// loop throught and add all other clauses
for (int i = 1; i < queries.size(); i++) {
log.debug("indexOp: {} and base: {} with range: {}", new Object[] {indexOp, base, range});
compiler.addScanIterator(indexOp.scanIndex(queries.get(i), keyspace));
}
int start = 0;
int size = Integer.MAX_VALUE;
if (range.start != 0 || range.end != Long.MAX_VALUE) {
start = (int) range.start;
size = (int) (range.end - range.start);
// this is a limitation in cassandra paging, more than an int isn't supported for loading
// columns. Not really an issue since that many rows propbably can't be loaded in ram anyway
}
// TODO T.N. incorporate LRS
compiler.compile(start, size);
CassandraResultObjectProvider results =
new CassandraResultObjectProvider(
compiler.getResults(),
this.getContext().getStoreContext(),
ctx.getFetchConfiguration(),
(CassandraClassMetaData) base);
return results;
}
/**
* Get the index for the query
*
* @param query
* @return
*/
private AbstractIndexOperation getIndexOp(
IndexQuery query,
Value[] ordering,
boolean[] orderAscending,
CassandraClassMetaData metaData) {
Collection<FieldExpression> expFields = query.getExpressions();
FieldOrder[] fields = new FieldOrder[expFields.size()];
IndexOrder[] orders = new IndexOrder[ordering.length];
Iterator<FieldExpression> expFieldsItr = expFields.iterator();
// all fields are ascending by default in field equality.
for (int i = 0; i < fields.length; i++) {
FieldExpression current = expFieldsItr.next();
// if there's not start but an end then this column must be
// descending in
// the index
fields[i] = new FieldOrder(current.getField().getName(), true);
log.debug("in getIndexOp with field: {}", fields[i]);
}
for (int i = 0; i < orders.length; i++) {
orders[i] = new IndexOrder(((Path) ordering[i]).last().getName(), orderAscending[i]);
}
EntityFacade classMeta = conf.getMetaCache().getFacade(metaData, conf.getSerializer());
AbstractIndexOperation indexOp = classMeta.getIndexOperation(fields, orders);
if (indexOp == null) {
throw new UnsupportedException(
String.format(
"You attempted to query an index that does not exist. To perform this query you must define an index in the following format. '%s'",
getIndexExpression(fields, orders)));
}
return indexOp;
}