Package net.sf.saxon.expr.sort
Class SortedIterator
java.lang.Object
net.sf.saxon.expr.sort.SortedIterator
- All Implemented Interfaces:
Closeable
,AutoCloseable
,LastPositionFinder
,SequenceIterator
,LookaheadIterator
- Direct Known Subclasses:
SortedGroupIterator
public class SortedIterator
extends Object
implements SequenceIterator, LastPositionFinder, LookaheadIterator
Class to do a sorted iteration
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Nested Class Summary
Nested classes/interfaces inherited from interface net.sf.saxon.om.SequenceIterator
SequenceIterator.Property
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected SequenceIterator
protected AtomicComparer[]
protected XPathContext
protected int
protected int
protected SortKeyEvaluator
protected ObjectToBeSorted[]
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Constructor Summary
ConstructorsModifierConstructorDescriptionprotected
SortedIterator
(XPathContext context, SequenceIterator base, SortKeyEvaluator sortKeyEvaluator, AtomicComparer[] comparators, boolean createNewContext) Create a sorted iterator -
Method Summary
Modifier and TypeMethodDescriptionprotected void
Create an array holding the items to be sorted and the values of their sort keysint
Get the last position (that is, the number of items in the sequence).Get properties of this iterator, as a bit-significant integer.boolean
hasNext()
Determine whether there are more items to come.next()
Get the next item, in sorted ordervoid
setHostLanguage
(HostLanguage language) Set the host languageMethods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Methods inherited from interface net.sf.saxon.om.SequenceIterator
close, forEachOrFail, materialize
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Field Details
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base
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sortKeyEvaluator
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comparators
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values
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count
protected int count -
position
protected int position -
context
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Constructor Details
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SortedIterator
protected SortedIterator() -
SortedIterator
public SortedIterator(XPathContext context, SequenceIterator base, SortKeyEvaluator sortKeyEvaluator, AtomicComparer[] comparators, boolean createNewContext) Create a sorted iterator- Parameters:
context
- the dynamic XPath evaluation contextbase
- an iterator over the sequence to be sortedsortKeyEvaluator
- an object that allows the n'th sort key for a given item to be evaluatedcomparators
- an array of AtomicComparers, one for each sort key, for comparing sort key valuescreateNewContext
- true if sort keys are computed relative to the item being sorted (as in XSLT but not XQuery)
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Method Details
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setHostLanguage
Set the host language- Parameters:
language
- the host language (for exampleHostLanguage.XQUERY
)
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hasNext
public boolean hasNext()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 setting
SequenceIterator.Property.LOOKAHEAD
- Specified by:
hasNext
in interfaceLookaheadIterator
- Returns:
- true if there are more items in the sequence
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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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getLength
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.Property.LAST_POSITION_FINDER
- Specified by:
getLength
in interfaceLastPositionFinder
- Returns:
- the number of items in the sequence
- Throws:
XPathException
- if an error occurs evaluating the sequence in order to determine the number of items
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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.Property.GROUNDED
,SequenceIterator.Property.LAST_POSITION_FINDER
, andSequenceIterator.Property.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
- if an error occurs for example in evaluating a sort key
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