net.sf.saxon.evpull
Class SequenceComposer
java.lang.Object
net.sf.saxon.evpull.SequenceComposer
- SequenceIterator
public class SequenceComposer
extends java.lang.Object
This class takes a sequence of pull events and composes them into a sequence of items. This involves building
any element or document nodes that are presented in decomposed form.
Note: this SequenceIterator does not implement the
getAnother()
method, which limits its use,
since
getAnother()
is needed to support the XPath
last()
function.
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.
|
static void | main(String[] args) - Main method for testing only
|
Item | next() - Get the next item in the sequence.
|
int | position() - Get the current position.
|
SequenceComposer
public SequenceComposer(EventIterator iter,
PipelineConfiguration pipe)
Create a sequence composer
iter
- the underlying event iteratorpipe
- the pipeline configuration
current
public Item current()
Get the current value in the sequence (the one returned by the
most recent call on next()). This will be null before the first
call of next(). This method does not change the state of the iterator.
- current in interface SequenceIterator
- the current item, the one most recently returned by a call on
next(). Returns null if next() has not been called, or if the end
of the sequence has been reached.
getAnother
public SequenceIterator getAnother()
throws XPathException
Get another SequenceIterator that iterates over the same items as the original,
but which is repositioned at the start of the sequence.
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.
- getAnother in interface SequenceIterator
- a SequenceIterator that iterates over the same items,
positioned before the first item
getProperties
public int getProperties()
Get properties of this iterator, as a bit-significant integer.
- getProperties in interface SequenceIterator
main
public static void main(String[] args)
throws Exception
Main method for testing only
next
public Item next()
throws XPathException
Get the next item in the sequence. This method changes the state of the
iterator, in particular it affects the result of subsequent calls of
position() and current().
- next in interface SequenceIterator
- the next item, or null if there are no more items. Once a call
on next() has returned null, no further calls should be made. The preferred
action for an iterator if subsequent calls on next() are made is to return
null again, and all implementations within Saxon follow this rule.
position
public int position()
Get the current position. This will usually be zero before the first call
on next(), otherwise it will be the number of times that next() has
been called. Once next() has returned null, the preferred action is
for subsequent calls on position() to return -1, but not all existing
implementations follow this practice. (In particular, the EmptyIterator
is stateless, and always returns 0 as the value of position(), whether
or not next() has been called.)
This method does not change the state of the iterator.
- position in interface SequenceIterator
- the current position, the position of the item returned by the
most recent call of next(). This is 1 after next() has been successfully
called once, 2 after it has been called twice, and so on. If next() has
never been called, the method returns zero. If the end of the sequence
has been reached, the value returned will always be <= 0; the preferred
value is -1.