Package net.sf.saxon.expr
Class PositionIterator
java.lang.Object
net.sf.saxon.expr.PositionIterator
- All Implemented Interfaces:
LookaheadIterator
,SequenceIterator
A PositionIterator selects a subsequence of a sequence
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Field Summary
Fields inherited from interface net.sf.saxon.om.SequenceIterator
ATOMIZABLE, GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD
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Method Summary
Modifier and TypeMethodDescriptioncurrent()
Get the current value in the sequence (the one returned by the most recent call on next()).Get another iterator to return the same nodesint
Get properties of this iterator, as a bit-significant integer.boolean
hasNext()
Test whether there are any more items available in the enumerationstatic SequenceIterator
make
(SequenceIterator base, int min, int max) Static factory method.next()
Get the next item if there is oneint
position()
Get the current position.
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Method Details
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make
Static factory method. Creates a PositionIterator, unless the base Iterator is an ArrayIterator, in which case it optimizes by creating a new ArrayIterator directly over the underlying array. This optimization is important when doing recursion over a node-set using repeated calls of $nodes[position()>1]- Parameters:
base
- An iteration of the items to be filteredmin
- The position of the first item to be included (base 1)max
- The position of the last item to be included (base 1)- Throws:
XPathException
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hasNext
public boolean hasNext()Test whether there are any more items available in the enumeration- Specified by:
hasNext
in interfaceLookaheadIterator
- Returns:
- true if there are more items in the sequence
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next
Get the next item if there is one- Specified by:
next
in interfaceSequenceIterator
- Returns:
- 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.
- Throws:
XPathException
- if an error occurs retrieving the next item
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current
Description copied from interface:SequenceIterator
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.- Specified by:
current
in interfaceSequenceIterator
- Returns:
- 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.
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position
public int position()Description copied from interface:SequenceIterator
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.
- Specified by:
position
in interfaceSequenceIterator
- Returns:
- 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 invalid input: '<'= 0; the preferred value is -1.
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getAnother
Get another iterator to return the same nodes- Specified by:
getAnother
in interfaceSequenceIterator
- Returns:
- a SequenceIterator that iterates over the same items, positioned before the first item
- Throws:
XPathException
- if any error occurs
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getProperties
public int getProperties()Get properties of this iterator, as a bit-significant integer.- Specified by:
getProperties
in interfaceSequenceIterator
- Returns:
- the properties of this iterator. This will be some combination of
properties such as
SequenceIterator.GROUNDED
,SequenceIterator.LAST_POSITION_FINDER
, andSequenceIterator.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.
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