Package net.sf.saxon.ma.zeno
Class ZenoSequence.ZenoSequenceIterator
java.lang.Object
net.sf.saxon.ma.zeno.ZenoSequence.ZenoSequenceIterator
- All Implemented Interfaces:
Closeable
,AutoCloseable
,LastPositionFinder
,SequenceIterator
,GroundedIterator
,LookaheadIterator
- Enclosing class:
ZenoSequence
public static class ZenoSequence.ZenoSequenceIterator
extends Object
implements GroundedIterator, LastPositionFinder, LookaheadIterator
A SequenceIterator over a ZenoSequence
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionint
Get the last position (that is, the number of items in the sequence).Return a GroundedValue containing all the remaining items in the sequence returned by this SequenceIterator, starting at the current position.boolean
hasNext()
Determine whether there are more items to come.boolean
Ask if the iterator is actually grounded.Create a GroundedValue (a sequence materialized in memory) containing all the values delivered by this SequenceIterator.next()
Get the next item in the sequence.boolean
Ask whether this iterator supports use of theLastPositionFinder.getLength()
method.boolean
Ask whether the hasNext() method can be called.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
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Constructor Details
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ZenoSequenceIterator
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Method Details
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next
Description copied from interface:SequenceIterator
Get the next item in the sequence. This method changes the state of the iterator.- 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.
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supportsGetLength
public boolean supportsGetLength()Description copied from interface:LastPositionFinder
Ask whether this iterator supports use of theLastPositionFinder.getLength()
method. This method should always be called before callingLastPositionFinder.getLength()
, because an iterator that implements this interface may support use ofLastPositionFinder.getLength()
in some situations and not in others- Specified by:
supportsGetLength
in interfaceLastPositionFinder
- Returns:
- true if the
LastPositionFinder.getLength()
method can be called to determine the length of the underlying sequence.
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getLength
public int 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 theLastPositionFinder.supportsGetLength()
has been called and has returned true.- Specified by:
getLength
in interfaceLastPositionFinder
- Returns:
- the number of items in the sequence
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isActuallyGrounded
public boolean isActuallyGrounded()Description copied from interface:GroundedIterator
Ask if the iterator is actually grounded. This method must be called before callingGroundedIterator.materialize()
orGroundedIterator.getResidue()
, because the iterator might be grounded under some conditions and not others (usually when it delegates to another iterator)- Specified by:
isActuallyGrounded
in interfaceGroundedIterator
- Returns:
- true if this iterator is grounded
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getResidue
Description copied from interface:GroundedIterator
Return a GroundedValue containing all the remaining items in the sequence returned by this SequenceIterator, starting at the current position. This should be an "in-memory" value, not a Closure. This method does not change the state of the iterator (in particular, it does not consume the iterator).- Specified by:
getResidue
in interfaceGroundedIterator
- Returns:
- the corresponding Value
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materialize
Description copied from interface:GroundedIterator
Create a GroundedValue (a sequence materialized in memory) containing all the values delivered by this SequenceIterator. The method must only be used when the SequenceIterator is positioned at the start. If it is not positioned at the start, then it is implementation-dependant whether the returned sequence contains all the nodes delivered by the SequenceIterator from the beginning, or only those delivered starting at the current position.It is implementation-dependant whether this method consumes the SequenceIterator. (More specifically, in the current implementation: if the iterator is backed by a
GroundedValue
, then that value is returned and the iterator is not consumed; otherwise, the iterator is consumed and the method returns the remaining items after the current position only).- Specified by:
materialize
in interfaceGroundedIterator
- Returns:
- a sequence containing all the items delivered by this SequenceIterator.
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supportsHasNext
public boolean supportsHasNext()Description copied from interface:LookaheadIterator
Ask whether the hasNext() method can be called. This method must be called before calling hasNext(), because some iterators implement this interface, but only support look-ahead under particular circumstances (this is usually because they delegate to another iterator)- Specified by:
supportsHasNext
in interfaceLookaheadIterator
- Returns:
- true if the
LookaheadIterator.hasNext()
method is available
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hasNext
public boolean hasNext()Description copied from interface:LookaheadIterator
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
LookaheadIterator.supportsHasNext()
is true.- Specified by:
hasNext
in interfaceLookaheadIterator
- Returns:
- true if there are more items in the sequence
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