public interface SequenceIterator
A SequenceIterator keeps track of the current Item and the current position. The objects returned by the SequenceIterator will always be either nodes (class NodeInfo) or singleton values (class AtomicValue): these are represented collectively by the interface Item.
This interface forms part of the public Saxon API. The JavaDoc "since" flag is used from release 8.4 onwards to indicate methods that are considered to be a stable part of the API. Methods without a "since" flag should not be regarded as a stable part of the API.
Note that the stability of this interface applies to classes that use the interface, not to classes that implement it. The interface may be extended in future to add new methods.
Modifier and Type | Field and Description |
---|---|
static int |
ATOMIZABLE
Property value: the iterator supports a setAtomizing() method, which requests (but does not require)
the iterator to atomize any nodes and return their typed values
|
static int |
GROUNDED
Property value: the iterator is "grounded".
|
static int |
LAST_POSITION_FINDER
Property value: the iterator knows the number of items that it will deliver.
|
static int |
LOOKAHEAD
Property value: the iterator knows whether there are more items still to come.
|
Modifier and Type | Method and Description |
---|---|
Item |
current()
Get the current value in the sequence (the one returned by the
most recent call on next()).
|
SequenceIterator |
getAnother()
Get another SequenceIterator that iterates over the same items as the original,
but which is repositioned at the start of the sequence.
|
int |
getProperties()
Get properties of this iterator, as a bit-significant integer.
|
Item |
next()
Get the next item in the sequence.
|
int |
position()
Get the current position.
|
static final int GROUNDED
GroundedIterator
, and (b) the
implementation of the materialize() method must be efficient (in particular,
it should not involve the creation of new objects)static final int LAST_POSITION_FINDER
LastPositionFinder
,
and (b) the implementation of the getLastPosition() method must be efficient (in particular,
it should take constant time, rather than time proportional to the length of the sequence)static final int LOOKAHEAD
LookaheadIterator
, and (b) the
implementation of the hasNext() method must be efficient (more efficient than the client doing
it)static final int ATOMIZABLE
Item next() throws XPathException
XPathException
- if an error occurs retrieving the next itemItem current()
int position()
This method does not change the state of the iterator.
SequenceIterator getAnother() throws XPathException
This method allows access to all the items in the sequence without disturbing the current position of the iterator. Internally, its main use is in evaluating the last() function.
This method does not change the state of the iterator.
XPathException
- if any error occursint getProperties()
GROUNDED
, LAST_POSITION_FINDER
,
and LOOKAHEAD
. It is always
acceptable to return the value zero, indicating that there are no known special properties.
It is acceptable for the properties of the iterator to change depending on its state.