Package net.sf.saxon.sort
Class SortedIterator
java.lang.Object
net.sf.saxon.sort.SortedIterator
- All Implemented Interfaces:
LastPositionFinder
,SequenceIterator
,Sortable
- Direct Known Subclasses:
SortedGroupIterator
,SortedTupleIterator
public class SortedIterator
extends Object
implements SequenceIterator, LastPositionFinder, Sortable
Class to do a sorted iteration
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected SequenceIterator
protected Comparator[]
protected XPathContext
protected int
protected int
protected Object[]
protected int
protected SortKeyDefinition[]
Fields inherited from interface net.sf.saxon.om.SequenceIterator
ATOMIZABLE, GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD
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Constructor Summary
ConstructorsConstructorDescriptionSortedIterator
(XPathContext context, SequenceIterator base, SortKeyDefinition[] sortkeys, Comparator[] comparators) -
Method Summary
Modifier and TypeMethodDescriptionprotected void
Create an array holding the items to be sorted and the values of their sort keysint
compare
(int a, int b) Compare two items in sorted sequence (needed to implement the Sortable interface)current()
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.int
Get the last position (that is, the number of items in the sequence).int
Get properties of this iterator, as a bit-significant integer.next()
Get the next item, in sorted orderint
position()
Get the current position.void
setHostLanguage
(int language) void
swap
(int a, int b) Swap two items (needed to implement the Sortable interface)
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Field Details
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base
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sortkeys
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comparators
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recordSize
protected int recordSize -
nodeKeys
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count
protected int count -
index
protected int index -
context
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Constructor Details
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SortedIterator
public SortedIterator(XPathContext context, SequenceIterator base, SortKeyDefinition[] sortkeys, Comparator[] comparators)
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Method Details
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setHostLanguage
public void setHostLanguage(int language) -
next
Get the next item, in sorted order- 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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getLastPosition
Description copied from interface:LastPositionFinder
Get the last position (that is, the number of items in the sequence). This method is non-destructive: it does not change the state of the iterator. The result is undefined if the next() method of the iterator has already returned null. This method must not be called unless the result of getProperties() on the iterator includes the bit settingSequenceIterator.LAST_POSITION_FINDER
- Specified by:
getLastPosition
in interfaceLastPositionFinder
- Throws:
XPathException
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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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buildArray
Create an array holding the items to be sorted and the values of their sort keys- Throws:
XPathException
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compare
public int compare(int a, int b) Compare two items in sorted sequence (needed to implement the Sortable interface) -
swap
public void swap(int a, int b) Swap two items (needed to implement the Sortable interface)
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