/**
* Checks if the given <code>InsertRow</code>s contain cyclic fk constraints.
*
* @param rows
* @return steps of the cycle, or null if there is none
*/
private static Collection<InsertRow> findCycle(Collection<InsertRow> rows) {
Iterator<InsertRow> rowsIter = rows.iterator();
while (rowsIter.hasNext()) {
InsertRow begin = rowsIter.next();
Iterator<InsertRow> refIter = begin.getReferencedRows().iterator();
while (refIter.hasNext()) {
InsertRow referencedRow = refIter.next();
List<InsertRow> cycle =
findCycleRecursion(referencedRow, begin, new ArrayList<InsertRow>());
if (cycle != null) {
return cycle;
}
}
}
return null;
}
private static List<InsertRow> findCycleRecursion(
InsertRow next, InsertRow begin, List<InsertRow> steps) {
if (steps.contains(next)) {
steps.add(next);
return steps;
}
steps.add(next);
Iterator<InsertRow> refIter = next.getReferencedRows().iterator();
while (refIter.hasNext()) {
InsertRow referencedRow = refIter.next();
List<InsertRow> cycle = findCycleRecursion(referencedRow, begin, steps);
if (cycle != null) {
return cycle;
}
}
steps.remove(steps.size() - 1);
return null;
}
