private static class Collections2.PermutationIterator<E> extends AbstractIterator<java.util.List<E>>
Modifier and Type | Field and Description |
---|---|
(package private) int[] |
c |
(package private) int |
j |
(package private) java.util.List<E> |
list |
(package private) int[] |
o |
Constructor and Description |
---|
PermutationIterator(java.util.List<E> list) |
Modifier and Type | Method and Description |
---|---|
(package private) void |
calculateNextPermutation() |
protected java.util.List<E> |
computeNext()
Returns the next element.
|
(package private) void |
switchDirection() |
endOfData, hasNext, next, peek
remove
final java.util.List<E> list
final int[] c
final int[] o
int j
PermutationIterator(java.util.List<E> list)
@CheckForNull protected java.util.List<E> computeNext()
AbstractIterator
AbstractIterator.endOfData()
when
there are no elements left in the iteration. Failure to do so could result in an infinite loop.
The initial invocation of AbstractIterator.hasNext()
or AbstractIterator.next()
calls this method, as does
the first invocation of hasNext
or next
following each successful call to
next
. Once the implementation either invokes endOfData
or throws an exception,
computeNext
is guaranteed to never be called again.
If this method throws an exception, it will propagate outward to the hasNext
or
next
invocation that invoked this method. Any further attempts to use the iterator will
result in an IllegalStateException
.
The implementation of this method may not invoke the hasNext
, next
, or
AbstractIterator.peek()
methods on this instance; if it does, an IllegalStateException
will
result.
computeNext
in class AbstractIterator<java.util.List<E>>
endOfData
was called during execution,
the return value will be ignored.void calculateNextPermutation()
void switchDirection()