public Any exec(Any a) throws AnyException {
Transaction t = getTransaction();
Composite sumRoot = (Composite) EvalExpr.evalFunc(t, a, sumRoot_, Composite.class);
if (sumRoot == null) nullOperand(sumRoot_);
Any expression = null;
Any sum = null;
Any tmp = null;
Adder adder = null;
if (takeAverage_ && sumRoot.entries() == 0) return null;
Iter i = sumRoot.createIterator();
Any loop = t.getLoop();
try {
while (i.hasNext()) {
Any child = i.next();
// Set $loop
t.setLoop(child);
// Lazy clone of expression
if (expression == null) {
expression = expression_.cloneAny();
}
if (sum == null) {
sum = EvalExpr.evalFunc(t, a, expression);
if (sum == null)
throw new NullPointerException("Failed to resolve " + expression_ + "during summation");
// To save on the creation of temporaries, the first sum
// item is used as the prototype for the result. The
// remaining items, if not the same, must be convertible to it.
adder = new Adder(sum);
sum = adder.add(sum);
tmp = sum.buildNew(null);
adder.setTmp(tmp);
} else {
Any next = EvalExpr.evalFunc(t, a, expression);
if (next == null)
throw new NullPointerException("Failed to resolve " + expression_ + "during summation");
adder.add(next);
}
// No point in continuing the iteration if we hit a null
if (adder.isNull()) break;
}
if (adder != null && adder.isNull()) return AnyNull.instance();
if (takeAverage_ && sum != null) return adder.doAvg(sum, sumRoot.entries());
return sum == null ? AnyNull.instance() : sum;
} finally {
t.setLoop(loop);
}
}
