Package net.sf.saxon.om
Class MemoSequence.ProgressiveIterator
java.lang.Object
net.sf.saxon.om.MemoSequence.ProgressiveIterator
- All Implemented Interfaces:
Closeable
,AutoCloseable
,LastPositionFinder
,SequenceIterator
,GroundedIterator
- Enclosing class:
- MemoSequence
public final class MemoSequence.ProgressiveIterator
extends Object
implements SequenceIterator, LastPositionFinder, GroundedIterator
A ProgressiveIterator starts by reading any items already held in the reservoir;
when the reservoir is exhausted, it reads further items from the inputIterator,
copying them into the reservoir as they are read.
-
Nested Class Summary
Nested classes/interfaces inherited from interface net.sf.saxon.om.SequenceIterator
SequenceIterator.Property
-
Field Summary
Fields -
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionvoid
close()
Close the iterator.int
Get the last position (that is, the number of items in the sequence)Get the containing MemoSequenceGet properties of this iterator, as a bit-significant integer.Return a GroundedValue containing all the remaining items in the sequence returned by this SequenceIterator, starting at the current position.Return a value containing all the items in the sequence returned by this SequenceIteratornext()
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
forEachOrFail
-
Field Details
-
position
int position
-
-
Constructor Details
-
ProgressiveIterator
public ProgressiveIterator()Create a ProgressiveIterator
-
-
Method Details
-
getMemoSequence
Get the containing MemoSequence -
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.
- Throws:
XPathException
- if an error occurs retrieving the next item
-
close
public void close()Description copied from interface:SequenceIterator
Close the iterator. This indicates to the supplier of the data that the client does not require any more items to be delivered by the iterator. This may enable the supplier to release resources. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.For example, the iterator returned by the unparsed-text-lines() function has a close() method that causes the underlying input stream to be closed, whether or not the file has been read to completion.
Closing an iterator is important when the data is being "pushed" in another thread. Closing the iterator terminates that thread and means that it needs to do no additional work. Indeed, failing to close the iterator may cause the push thread to hang waiting for the buffer to be emptied.
- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceCloseable
- Specified by:
close
in interfaceSequenceIterator
-
getLength
Get the last position (that is, the number of items in the sequence)- 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
-
materialize
Return a value containing all the items in the sequence returned by this SequenceIterator- Specified by:
materialize
in interfaceGroundedIterator
- Specified by:
materialize
in interfaceSequenceIterator
- Returns:
- the corresponding value
- Throws:
XPathException
- if reading the SequenceIterator throws an error
-
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
- Throws:
XPathException
- in the cases of subclasses (such as the iterator over a MemoClosure) which cause evaluation of expressions while materializing the value.
-
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
andSequenceIterator.Property.LAST_POSITION_FINDER
. It is always acceptable to return the value zero, indicating that there are no known special properties.
-