@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();
}
/**
* Converts the specified result to an XQuery value.
*
* @param obj result object
* @param qc query context
* @param sc static context
* @return value
* @throws QueryException query exception
*/
public static Value toValue(final Object obj, final QueryContext qc, final StaticContext sc)
throws QueryException {
if (obj == null) return Empty.SEQ;
if (obj instanceof Value) return (Value) obj;
if (obj instanceof Iter) return ((Iter) obj).value();
// find XQuery mapping for specified type
final Type type = type(obj);
if (type != null) return type.cast(obj, qc, sc, null);
// primitive arrays
if (obj instanceof byte[]) return BytSeq.get((byte[]) obj);
if (obj instanceof long[]) return IntSeq.get((long[]) obj, AtomType.ITR);
if (obj instanceof char[]) return Str.get(new String((char[]) obj));
if (obj instanceof boolean[]) return BlnSeq.get((boolean[]) obj);
if (obj instanceof double[]) return DblSeq.get((double[]) obj);
if (obj instanceof float[]) return FltSeq.get((float[]) obj);
// no array: return Java type
if (!obj.getClass().isArray()) return new Jav(obj, qc);
// empty array
final int s = Array.getLength(obj);
if (s == 0) return Empty.SEQ;
// string array
if (obj instanceof String[]) {
final String[] r = (String[]) obj;
final byte[][] b = new byte[r.length][];
for (int v = 0; v < s; v++) b[v] = token(r[v]);
return StrSeq.get(b);
}
// character array
if (obj instanceof char[][]) {
final char[][] r = (char[][]) obj;
final byte[][] b = new byte[r.length][];
for (int v = 0; v < s; v++) b[v] = token(new String(r[v]));
return StrSeq.get(b);
}
// short array
if (obj instanceof short[]) {
final short[] r = (short[]) obj;
final long[] b = new long[r.length];
for (int v = 0; v < s; v++) b[v] = r[v];
return IntSeq.get(b, AtomType.SHR);
}
// integer array
if (obj instanceof int[]) {
final int[] r = (int[]) obj;
final long[] b = new long[r.length];
for (int v = 0; v < s; v++) b[v] = r[v];
return IntSeq.get(b, AtomType.INT);
}
// any other array (also nested ones)
final Object[] objs = (Object[]) obj;
final ValueBuilder vb = new ValueBuilder(objs.length);
for (final Object o : objs) vb.add(toValue(o, qc, sc));
return vb.value();
}
@Override
public Expr compile(final QueryContext ctx) throws QueryException {
for (int e = 0; e < expr.length; e++) expr[e] = expr[e].compile(ctx);
// compute number of results
size = 0;
for (final Expr e : expr) {
final long c = e.size();
if (c == -1) {
size = c;
break;
}
size += c;
}
// evaluate sequence type
type = SeqType.EMP;
Value[] val = new Value[expr.length];
for (int v = 0; v < expr.length; v++) {
final Expr e = expr[v];
// check if all expressions are values
if (val != null) {
if (e.isValue()) val[v] = (Value) e;
else val = null;
}
// skip expression that will not add any results
if (e.isEmpty()) continue;
// evaluate sequence type
final SeqType et = e.type();
type =
type == SeqType.EMP
? et
: SeqType.get(
et.type == type.type ? et.type : AtomType.ITEM,
et.mayBeZero() && type.mayBeZero() ? Occ.ZERO_MORE : Occ.ONE_MORE);
}
// return cached integer sequence, cached values or self reference
Expr e = this;
final int s = (int) size;
if (val != null && size <= Integer.MAX_VALUE) {
if (type.type == AtomType.STR) e = StrSeq.get(val, s);
else if (type.type == AtomType.BLN) e = BlnSeq.get(val, s);
else if (type.type == AtomType.FLT) e = FltSeq.get(val, s);
else if (type.type == AtomType.DBL) e = DblSeq.get(val, s);
else if (type.type == AtomType.DEC) e = DecSeq.get(val, s);
else if (type.type == AtomType.BYT) e = BytSeq.get(val, s);
else if (type.type.instanceOf(AtomType.ITR)) e = IntSeq.get(val, s, type.type);
else {
final ValueBuilder vb = new ValueBuilder(s);
for (final Value v : val) vb.add(v);
e = vb.value();
}
}
return optPre(e, ctx);
}
/**
* Binds the specified parameter to a variable.
*
* @param rxp parameter
* @param args argument array
* @param values values to be bound; the parameter's default value is assigned if the argument is
* {@code null} or empty
* @throws QueryException query exception
*/
private void bind(final RestXqParam rxp, final Expr[] args, final String... values)
throws QueryException {
final Value val;
if (values == null || values.length == 0) {
val = rxp.value;
} else {
final ValueBuilder vb = new ValueBuilder();
for (final String s : values) vb.add(new Atm(s));
val = vb.value();
}
bind(rxp.name, args, val);
}
@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;
}
/**
* Returns a parameter.
*
* @param value value
* @param name name
* @param declared variable declaration flags
* @return parameter
* @throws QueryException HTTP exception
*/
private RestXqParam param(final Value value, final QNm name, final boolean[] declared)
throws QueryException {
// [CG] RESTXQ: allow identical field names?
final long vs = value.size();
if (vs < 2) error(ANN_PARAMS, "%", name.string(), 2);
// name of parameter
final String key = toString(value.itemAt(0), name);
// variable template
final QNm qnm = checkVariable(toString(value.itemAt(1), name), declared);
// default value
final ValueBuilder vb = new ValueBuilder();
for (int v = 2; v < vs; v++) vb.add(value.itemAt(v));
return new RestXqParam(qnm, key, vb.value());
}
@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 Value value(final QueryContext ctx) throws QueryException {
final ValueBuilder vb = new ValueBuilder();
for (final Expr e : expr) vb.add(ctx.value(e));
return vb.value();
}
@Override
public Value value(final QueryContext qc) {
final ValueBuilder vb = new ValueBuilder();
for (final Object k : System.getenv().keySet()) vb.add(Str.get(k.toString()));
return vb.value();
}