TupleList SimpleQueryLinker::make_tuples(
const std::vector<std::string>& variables)
{
TupleList result;
std::string first_qvar = *variables.begin();
if(!is_initialized(first_qvar)) {
throw QueryLinkerError();
}
for(ConditionSet::iterator cit = _qvar_table[first_qvar].begin();
cit != _qvar_table[first_qvar].end(); ++cit)
{
TupleList tuples = make_tuples(first_qvar, *cit,
++variables.begin(), variables.end());
for(TupleList::iterator tit = tuples.begin();
tit != tuples.end(); ++tit)
{
result.insert(*tit);
}
}
return result;
}
void SimpleQueryLinker::merge_tuples(const ConditionPtr& target_condition,
const TupleList& tuples, TupleList& result)
{
for(TupleList::const_iterator tit = tuples.begin();
tit != tuples.end(); ++tit)
{
result.insert(ConditionTuplePtr(
new SimpleConditionTuple(target_condition, *tit)));
}
}
TupleList SimpleQueryLinker::make_tuples(
const std::string& current_qvar,
const ConditionPtr& current_condition,
std::vector<std::string>::const_iterator next_qit,
std::vector<std::string>::const_iterator end)
{
if(!is_initialized(current_qvar)) {
throw QueryLinkerError();
}
TupleList result;
if(next_qit == end) {
result.insert(ConditionTuplePtr(
new SimpleConditionTuple(current_condition)));
} else {
std::string next_qvar = *next_qit++;
if(has_link(current_qvar, next_qvar)) {
ConditionSet linked_conditions = get_linked_conditions(
current_qvar, next_qvar, current_condition);
for(ConditionSet::iterator cit = linked_conditions.begin();
cit != linked_conditions.end(); ++cit)
{
merge_tuples(current_condition,
make_tuples(next_qvar, *cit, next_qit, end),
result);
}
} else if(has_indirect_links(current_qvar, next_qvar)) {
ConditionSet linked_conditions = get_indirect_links(
current_qvar, next_qvar, current_condition);
for(ConditionSet::iterator cit = linked_conditions.begin();
cit != linked_conditions.end(); ++cit)
{
merge_tuples(current_condition,
make_tuples(next_qvar, *cit, next_qit, end),
result);
}
} else {
for(ConditionSet::iterator cit = _qvar_table[next_qvar].begin();
cit != _qvar_table[next_qvar].end(); ++cit)
{
merge_tuples(current_condition,
make_tuples(next_qvar, *cit, next_qit, end),
result);
}
}
}
return result;
}