Package com.saxonica.ee.optim

Class MultiIndex.SelectedItemsIterator

java.lang.Object

com.saxonica.ee.optim.MultiIndex.SelectedItemsIterator

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, LastPositionFinder, SequenceIterator, LookaheadIterator

Enclosing class:

MultiIndex

public static class MultiIndex.SelectedItemsIterator
extends java.lang.Object
implements SequenceIterator, LastPositionFinder, LookaheadIterator

Iterator over a subset of the items in this IndexedValue, identified by an IntSet holding the positions of the items in the selected subset (zero-based)

Nested Class Summary

Nested classes/interfaces inherited from interface net.sf.saxon.om.SequenceIterator

SequenceIterator.Property

Constructor Summary

Constructors

Constructor	Description
SelectedItemsIterator(GroundedValue indexedValue, IntSet selection)

Method Summary

Modifier and Type	Method	Description
int	getLength()	Get the last position (that is, the number of items in the sequence).
java.util.EnumSet<SequenceIterator.Property>	getProperties()	Get properties of this iterator, as a bit-significant integer.
boolean	hasNext()	Determine whether there are more items to come.
Item	next()	Get the next item in the sequence.

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.om.SequenceIterator

close, forEachOrFail, materialize

Constructor Detail

SelectedItemsIterator

public SelectedItemsIterator(GroundedValue indexedValue,
                             IntSet selection)

Method Detail

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 interface LookaheadIterator

Returns:

true if there are more items in the sequence

next

public Item next()
          throws XPathException

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 interface SequenceIterator

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

Since:

8.4

getLength

public int getLength()
              throws XPathException

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 setting SequenceIterator.Property.LAST_POSITION_FINDER

Specified by:

getLength in interface LastPositionFinder

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

getProperties

public java.util.EnumSet<SequenceIterator.Property> getProperties()

Get properties of this iterator, as a bit-significant integer.

Specified by:

getProperties in interface SequenceIterator

Returns:

the properties of this iterator. This will be some combination of properties such as SequenceIterator.Property.GROUNDED, SequenceIterator.Property.LAST_POSITION_FINDER, and SequenceIterator.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.

Since:

8.6