Package net.sf.saxon.expr.sort
Interface GroupIterator
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- All Superinterfaces:
java.lang.AutoCloseable
,java.io.Closeable
,SequenceIterator
- All Known Implementing Classes:
GroupAdjacentIterator
,GroupBreakingIterator
,GroupByIterator
,GroupEndingIterator
,GroupMatchingIterator
,GroupStartingIterator
,ManualGroupIterator
,MergeGroupingIterator
,SortedGroupIterator
public interface GroupIterator extends SequenceIterator
A GroupIterator is an iterator that iterates over a sequence of groups. The normal methods such as next() and current() always deliver the leading item of the group. Additional methods are available to get the grouping key for the current group (only applicable to group-by and group-adjacent), and to get all the members of the current group.
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Method Summary
All Methods Instance Methods Abstract Methods Modifier and Type Method Description GroundedValue
currentGroup()
Get a sequence containing the members of the current group, in population order.AtomicSequence
getCurrentGroupingKey()
Get the grouping key of the current groupManualGroupIterator
getSnapShot(XPathContext context)
Get a pseudo-iterator which represents a snapshot of this sequence at the current position-
Methods inherited from interface net.sf.saxon.om.SequenceIterator
close, next
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Method Detail
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getCurrentGroupingKey
AtomicSequence getCurrentGroupingKey()
Get the grouping key of the current group- 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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currentGroup
GroundedValue currentGroup() throws XPathException
Get a sequence containing the members of the current group, in population order. This may be a MemoSequence rather than a grounded value- Returns:
- a sequence containing all the members of the current group, in population order.
- Throws:
XPathException
- if a dynamic error occurs
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getSnapShot
ManualGroupIterator getSnapShot(XPathContext context) throws XPathException
Get a pseudo-iterator which represents a snapshot of this sequence at the current position- Parameters:
context
- the XPath context- Returns:
- the snapshot sequence
- Throws:
XPathException
- if any error occurs
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