@Override
public Value value(final QueryContext qc) throws QueryException {
final FItem getKey = checkArity(exprs[1], 1, qc);
final long k = Math.min(toLong(exprs[2], qc), Integer.MAX_VALUE);
if (k < 1) return Empty.SEQ;
final Iter iter = exprs[0].iter(qc);
final MinHeap<Item, Item> heap =
new MinHeap<>(
new Comparator<Item>() {
@Override
public int compare(final Item it1, final Item it2) {
try {
return OpV.LT.eval(it1, it2, sc.collation, sc, info) ? -1 : 1;
} catch (final QueryException qe) {
throw new QueryRTException(qe);
}
}
});
try {
for (Item it; (it = iter.next()) != null; ) {
heap.insert(checkNoEmpty(getKey.invokeItem(qc, info, it)), it);
if (heap.size() > k) heap.removeMin();
}
} catch (final QueryRTException ex) {
throw ex.getCause();
}
final ValueBuilder vb = new ValueBuilder();
while (!heap.isEmpty()) vb.addFront(heap.removeMin());
return vb.value();
}
@Override
public Item item(final QueryContext qc, final InputInfo ii) throws QueryException {
final Iter ir = iter(qc);
final Item it = ir.next();
if (it == null || ir.size() == 1) return it;
final Item n = ir.next();
if (n != null) {
final ValueBuilder vb = new ValueBuilder().add(it).add(n);
if (ir.next() != null) vb.add(Str.get(DOTS));
throw SEQFOUND_X.get(info, vb.value());
}
return it;
}
@Override
public Value value(final QueryContext qc) throws QueryException {
final FItem f = checkArity(exprs[1], 1, qc);
final Iter iter = exprs[0].iter(qc);
Item it = iter.next();
if (it == null) return Empty.SEQ;
final Value v1 = f.invokeValue(qc, info, it);
it = iter.next();
if (it == null) return v1;
final ValueBuilder vb = new ValueBuilder().add(v1);
do {
vb.add(f.invokeValue(qc, info, it));
} while ((it = iter.next()) != null);
return vb.value();
}
@Override
public final Item ebv(final QueryContext qc, final InputInfo ii) throws QueryException {
final Item it;
if (seqType().zeroOrOne()) {
it = item(qc, info);
} else {
final Iter ir = iter(qc);
it = ir.next();
if (it != null && !(it instanceof ANode)) {
final Item n = ir.next();
if (n != null) {
final ValueBuilder vb = new ValueBuilder().add(it).add(n);
if (ir.next() != null) vb.add(Str.get(DOTS));
throw EBV_X.get(info, vb.value());
}
}
}
return it == null ? Bln.FALSE : it;
}
@Override
public Iter iter(final QueryContext qc) throws QueryException {
final Iter ir = exprs[0].iter(qc);
final long len = ir.size();
if (len == 0) throw ONEORMORE.get(info);
if (len > 0) return ir;
return new Iter() {
private boolean first = true;
@Override
public Item next() throws QueryException {
final Item it = ir.next();
if (first) {
if (it == null) throw ONEORMORE.get(info);
first = false;
}
return it;
}
};
}
/**
* Returns a minimum or maximum item.
*
* @param cmp comparator
* @param qc query context
* @return resulting item
* @throws QueryException query exception
*/
Item minmax(final OpV cmp, final QueryContext qc) throws QueryException {
final Collation coll = toCollation(1, qc);
final Iter iter = exprs[0].atomIter(qc, info);
Item curr = iter.next();
if (curr == null) return null;
// check if first item is comparable
cmp.eval(curr, curr, coll, sc, info);
// strings
if (curr instanceof AStr) {
for (Item it; (it = iter.next()) != null; ) {
if (!(it instanceof AStr)) throw EXPTYPE_X_X_X.get(info, curr.type, it.type, it);
final Type rt = curr.type, ri = it.type;
if (cmp.eval(curr, it, coll, sc, info)) curr = it;
if (rt != ri && curr.type == URI) curr = STR.cast(curr, qc, sc, info);
}
return curr;
}
// dates, durations, booleans, binary values
if (curr instanceof ADate || curr instanceof Dur || curr instanceof Bin || curr.type == BLN) {
for (Item it; (it = iter.next()) != null; ) {
if (curr.type != it.type) throw EXPTYPE_X_X_X.get(info, curr.type, it.type, it);
if (cmp.eval(curr, it, coll, sc, info)) curr = it;
}
return curr;
}
// numbers
if (curr.type.isUntyped()) curr = DBL.cast(curr, qc, sc, info);
for (Item it; (it = iter.next()) != null; ) {
final Type type = numType(curr, it);
if (cmp.eval(curr, it, coll, sc, info) || Double.isNaN(it.dbl(info))) curr = it;
if (type != null) curr = (Item) type.cast(curr, qc, sc, info);
}
return curr;
}
/**
* Evaluates the specified function and creates a response.
*
* @throws Exception exception (including unexpected ones)
*/
void create() throws Exception {
// bind variables
final StaticFunc sf = function.function;
final Expr[] args = new Expr[sf.args.length];
function.bind(http, args, error);
// wrap function with a function call
final MainModule mm = new MainModule(sf, args);
// assign main module and http context and register process
query.mainModule(mm);
query.http(http);
query.context.register(query);
String redirect = null, forward = null;
RestXqRespBuilder resp = null;
try {
// compile and evaluate query
query.compile();
final Iter iter = query.iter();
Item item = iter.next();
// handle response element
if (item != null && item instanceof ANode) {
final ANode node = (ANode) item;
// send redirect to browser
if (REST_REDIRECT.eq(node)) {
final ANode ch = node.children().next();
if (ch == null || ch.type != NodeType.TXT) throw function.error(NO_VALUE, node.name());
redirect = string(ch.string()).trim();
return;
}
// server-side forwarding
if (REST_FORWARD.eq(node)) {
final ANode ch = node.children().next();
if (ch == null || ch.type != NodeType.TXT) throw function.error(NO_VALUE, node.name());
forward = string(ch.string()).trim();
return;
}
if (REST_RESPONSE.eq(node)) {
resp = new RestXqRespBuilder();
resp.build(node, function, iter, http);
return;
}
}
// HEAD method must return a single response element
if (function.methods.size() == 1 && function.methods.contains(HTTPMethod.HEAD.name()))
throw function.error(HEAD_METHOD);
// serialize result
final SerializerOptions sp = function.output;
http.sopts(sp);
http.initResponse();
final Serializer ser = Serializer.get(http.res.getOutputStream(), sp);
for (; item != null; item = iter.next()) ser.serialize(item);
ser.close();
} finally {
query.close();
query.context.unregister(query);
if (redirect != null) {
http.res.sendRedirect(redirect);
} else if (forward != null) {
http.req.getRequestDispatcher(forward).forward(http.req, http.res);
} else if (resp != null) {
if (resp.status != 0) http.status(resp.status, resp.message, resp.error);
http.res.getOutputStream().write(resp.cache.toArray());
}
}
}
