How to use

State$PermutationIterator

in

cascading.flow.planner.iso.finder

@Override
protected List<E> computeNext()
 {
 if( j <= 0 )
  return endOfData();
 List<E> next = Collections.unmodifiableList( new ArrayList<>( list ) );
 calculateNextPermutation();
 return next;
 }

 range.add( i );
PermutationIterator<Integer> iterator = new PermutationIterator<>( range );
boolean[][] transformed = new boolean[ matchers.size() ][];
while( iterator.hasNext() )
 List<Integer> permutation = iterator.next();

void calculateNextPermutation()
 {
 j = list.size() - 1;
 int s = 0;
 // Handle the special case of an empty list. Skip the calculation of the
 // next permutation.
 if( j == -1 )
  return;
 while( true )
  {
  int q = c[ j ] + o[ j ];
  if( q < 0 )
   {
   switchDirection();
   continue;
   }
  if( q == j + 1 )
   {
   if( j == 0 )
    break;
   s++;
   switchDirection();
   continue;
   }
  Collections.swap( list, j - c[ j ] + s, j - q + s );
  c[ j ] = q;
  break;
  }
 }