net.sf.saxon.expr.sort

Class GroupStartingIterator

java.lang.Object

net.sf.saxon.expr.sort.GroupMatchingIterator

net.sf.saxon.expr.sort.GroupStartingIterator

All Implemented Interfaces:

GroupIterator, SequenceIterator, LookaheadIterator

public class GroupStartingIterator
extends GroupMatchingIterator
implements LookaheadIterator, GroupIterator

A GroupStartingIterator iterates over a sequence of groups defined by xsl:for-each-group group-starting-with="x". The groups are returned in order of first appearance.

Field Summary

Fields inherited from class net.sf.saxon.expr.sort.GroupMatchingIterator

baseContext, current, currentMembers, next, pattern, population, position, runningContext

Fields inherited from interface net.sf.saxon.om.SequenceIterator

GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Constructor Summary

Constructors

Constructor and Description
GroupStartingIterator(SequenceIterator population, Pattern startPattern, XPathContext context)

Method Summary

Methods

Modifier and Type	Method and Description
protected void	advance()
SequenceIterator	getAnother() Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.

Methods inherited from class net.sf.saxon.expr.sort.GroupMatchingIterator

close, current, getCurrentGroupingKey, getProperties, getSnapShot, hasCurrentGroup, hasCurrentGroupingKey, hasNext, iterateCurrentGroup, next, position, setGroupSlot, setKeySlot

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface net.sf.saxon.tree.iter.LookaheadIterator

hasNext

Methods inherited from interface net.sf.saxon.expr.sort.GroupIterator

getCurrentGroupingKey, getSnapShot, hasCurrentGroup, hasCurrentGroupingKey, iterateCurrentGroup, setGroupSlot, setKeySlot

Methods inherited from interface net.sf.saxon.om.SequenceIterator

close, current, getProperties, next, position

Constructor Detail

GroupStartingIterator

public GroupStartingIterator(SequenceIterator population,
                     Pattern startPattern,
                     XPathContext context)
                      throws XPathException

Throws:

XPathException

Method Detail

advance

protected void advance()
                throws XPathException

Specified by:

advance in class GroupMatchingIterator

Throws:

XPathException

getAnother

public SequenceIterator getAnother()
                            throws XPathException

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.

Some implementations of this method may regenerate the input sequence, creating new nodes with different identity from the original. This is not recommended, but is hard to prevent. This causes no problem for the primary usage of this method to support the last() function, but it has been known to cause trouble in other situations.

Specified by:

getAnother in interface SequenceIterator

Returns:

a SequenceIterator that iterates over the same items, positioned before the first item

Throws:

XPathException - if any error occurs