PermutationFactory (JGraphT : a free Java graph library)

```
public class PermutationFactory
extends Object
```
Factory to create Permutations of several types and use them as Enumerations. Note that callers may use them directly if they need to use special concrete methods.
These types are:
All elements are different. There are N! possible permutations.
example: source=[1,2,3] result=[1,2,3][1,3,2][2,1,3][2,3,1][3,1,2][3,2,1]
Some of the elements are the same.
example: source=[1,1,2] result=[1,1,2][1,2,1][2,1,1]
There are separate permutations groups, which are connected to one sequence. Permutations are allowed only inside the group. Possible sequences: product of factorial of each group. see example.
example: assume source=the groups are sizes are : 1,2,2,5 elements will be created: (1),(2,3),(4,5).
result=[1,(2,3),(4,5)] [1,(2,3),(5,4)] [1,(3,2),(5,4)] [1,(3,2),(4,5)]. In this example the number of possiblities is 1! x 2! x 2! = 4

Constructors
Constructor and Description
`PermutationFactory()`

Methods
Modifier and Type	Method and Description
`static ArrayPermutationsIter`	`createByGroups(int[] groupSizesArray)` For efficiency, try putting the biggest groups at the beggining of the array.
`static ArrayPermutationsIter`	`createRegular(int[] permSourceArray)`

Class PermutationFactory