Package net.sf.saxon.sort
Class GroupEndingIterator
java.lang.Object
net.sf.saxon.sort.GroupEndingIterator
- All Implemented Interfaces:
LookaheadIterator
,SequenceIterator
,GroupIterator
A GroupEndingIterator iterates over a sequence of groups defined by
xsl:for-each-group group-ending-with="x". The groups are returned in
order of first appearance.
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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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Constructor Summary
ConstructorsConstructorDescriptionGroupEndingIterator
(SequenceIterator population, Pattern endPattern, XPathContext context) -
Method Summary
Modifier and TypeMethodDescriptioncurrent()
Get the current value in the sequence (the one returned by the most recent call on next()).Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.Get the grouping key of the current groupint
Get properties of this iterator, as a bit-significant integer.boolean
hasNext()
Determine whether there are more items to come.Get an iterator over the members of the current group, in population order.next()
Get the next item in the sequence.int
position()
Get the current position.
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Constructor Details
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GroupEndingIterator
public GroupEndingIterator(SequenceIterator population, Pattern endPattern, XPathContext context) throws XPathException - Throws:
XPathException
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Method Details
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getCurrentGroupingKey
Description copied from interface:GroupIterator
Get the grouping key of the current group- Specified by:
getCurrentGroupingKey
in interfaceGroupIterator
- Returns:
- the current grouping key in the case of group-by or group-adjacent, or null in the case of group-starting-with and group-ending-with
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iterateCurrentGroup
Description copied from interface:GroupIterator
Get an iterator over the members of the current group, in population order. This must always be a clean iterator, that is, an iterator that starts at the first item of the group.- Specified by:
iterateCurrentGroup
in interfaceGroupIterator
- Returns:
- an iterator over all the members of the current group, in population order.
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hasNext
public boolean hasNext()Description copied from interface:LookaheadIterator
Determine whether there are more items to come. Note that this operation is stateless and it is not necessary (or usual) to call it before calling next(). It is used only when there is an explicit need to tell if we are at the last element. This method must not be called unless the result of getProperties() on the iterator includes the bit settingSequenceIterator.LOOKAHEAD
- Specified by:
hasNext
in interfaceLookaheadIterator
- Returns:
- true if there are more items in the sequence
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next
Description copied from interface:SequenceIterator
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().- 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
Description copied from interface:SequenceIterator
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.
- 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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