private void combineParts(
MultiMap<Part, ColumnKey> needed,
MultiMap<ColumnKey, Part> classified,
List<ExpressionNode> andexprs,
List<Part> andparts) {
Part p = needed.keySet().iterator().next();
Collection<ColumnKey> missing = needed.get(p);
if (missing == null || missing.isEmpty()) {
andexprs.add((ExpressionNode) p.getParent());
needed.remove(p);
andparts.add(p);
return;
}
ListSet<Part> containingMissing = new ListSet<Part>();
boolean first = true;
for (ColumnKey ck : missing) {
Collection<Part> matching = classified.get(ck);
if (matching == null || matching.isEmpty()) continue;
if (first) containingMissing.addAll(matching);
else {
containingMissing.retainAll(matching);
}
}
if (containingMissing.isEmpty()) {
andexprs.add((ExpressionNode) p.getParent());
andparts.add(p);
needed.remove(p);
} else {
ListSet<Part> toCombine = new ListSet<Part>();
toCombine.add(p);
toCombine.addAll(containingMissing);
ListSet<Part> toRemove = new ListSet<Part>();
toRemove.addAll(toCombine);
Part clhs = choosePartForAndCombo(toCombine);
toCombine.remove(clhs);
while (!toCombine.isEmpty()) {
Part crhs = choosePartForAndCombo(toCombine);
toCombine.remove(crhs);
clhs = combineParts(clhs, crhs);
}
for (Part rp : toRemove) {
needed.remove(rp);
ArrayList<ColumnKey> classKeys = new ArrayList<ColumnKey>(classified.keySet());
for (ColumnKey ck : classKeys) {
Collection<Part> sub = classified.get(ck);
if (sub == null || sub.isEmpty()) continue;
if (sub.contains(rp)) classified.remove(ck, rp);
}
}
andexprs.add((ExpressionNode) clhs.getParent());
andparts.add(clhs);
}
}
