/**
* Retains the pairs obtained from the Cartesian product of transactions and items
*
* @param trans collection of transactions
* @param item the item
* @return <code>true</code> if the set set has been changed
*/
public boolean retainAll(Collection<T> trans, I item) {
if (isEmpty()) return false;
if (trans == null || trans.isEmpty() || item == null) {
clear();
return true;
}
return matrix.retainAll(allTransactions.convert(trans).indices(), itemToIndex(item));
}
/**
* Retains the pairs obtained from the Cartesian product of transactions and items
*
* @param trans the transaction
* @param items collection of items
* @return <code>true</code> if the set set has been changed
*/
public boolean retainAll(T trans, Collection<I> items) {
if (isEmpty()) return false;
if (trans == null || items == null || items.isEmpty()) {
clear();
return true;
}
return matrix.retainAll(transactionToIndex(trans), allItems.convert(items).indices());
}