PermutationGenerator (Groovy 6.0.0-alpha-1)

Summary:
Constructor
Method

| Detail:
Constructor
Method

groovy.util.PermutationGenerator

All Implemented Interfaces and Traits:

Iterator
```
public class PermutationGenerator<E>
extends Object
implements Iterator
```
Systematically generate permutations. Adapted from Java Code by Michael Gilleland (released with no restrictions) using an algorithm described here: Kenneth H. Rosen, Discrete Mathematics and Its Applications, 2nd edition (NY: McGraw-Hill, 1991), pp. 282-284

Constructor Summary

Constructors
Constructor and description
`PermutationGenerator(Collection<E> items)` WARNING: Don't make n too large.
`PermutationGenerator(Iterable<E> items)` Creates a generator from the supplied iterable.

Methods Summary

Methods
Type Params	Return Type	Name and description
	`public BigInteger`	`getTotal()` Returns the total number of permutations.
	`public boolean`	`hasNext()` {@inheritDoc}
	`public List<E>`	`next()` Generate next permutation (algorithm from Rosen p. 284)
	`public void`	`remove()` {@inheritDoc}
	`public void`	`reset()` Resets the generator to its initial state.

Inherited Methods Summary

Inherited Methods
Methods inherited from class	Name
`class Object`	`equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- Constructor Detail
  - public PermutationGenerator(Collection<E> items)
    
    WARNING: Don't make n too large. Recall that the number of permutations is n! which can be very large, even when n is as small as 20 -- 20! = 2,432,902,008,176,640,000 and 21! is too big to fit into a Java long, which is why we use BigInteger instead.
    Parameters:
    items - the items to permute
  - public PermutationGenerator(Iterable<E> items)
    
    Creates a generator from the supplied iterable.
    Parameters:
    items - the items to permute
- Method Detail
  - public BigInteger getTotal()
    
    Returns the total number of permutations.
    Returns:
    the total permutation count
  - public boolean hasNext()
    
    {@inheritDoc}
  - public List<E> next()
    
    Generate next permutation (algorithm from Rosen p. 284)
    Returns:
    the items permuted
  - public void remove()
    
    {@inheritDoc}
  - public void reset()
    
    Resets the generator to its initial state.

Summary:
Constructor
Method

| Detail:
Constructor
Method

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