net.sf.saxon.expr.instruct
Class BlockIterator

java.lang.Object
  extended by net.sf.saxon.expr.instruct.BlockIterator
All Implemented Interfaces:
SequenceIterator<Item>

public class BlockIterator
extends Object
implements SequenceIterator<Item>

Iterate over the instructions in the Block, concatenating the result of each instruction into a single combined sequence.


Field Summary
 
Fields inherited from interface net.sf.saxon.om.SequenceIterator
GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD
 
Constructor Summary
BlockIterator(Expression[] children, XPathContext context)
           
 
Method Summary
 void close()
          Close the iterator.
 Item current()
          Get the current value in the sequence (the one returned by the most recent call on next()).
 BlockIterator getAnother()
          Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.
 int getProperties()
          Get properties of this iterator, as a bit-significant integer.
 Item next()
          Get the next item in the sequence.
 int position()
          Get the current position.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

BlockIterator

public BlockIterator(Expression[] children,
                     XPathContext context)
Method Detail

next

public Item next()
          throws XPathException
Get the next item in the sequence.

Specified by:
next in interface SequenceIterator<Item>
Returns:
the next item, or null if there are no more items.
Throws:
XPathException - if an error occurs retrieving the next item

current

public Item current()
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().

Specified by:
current in interface SequenceIterator<Item>
Returns:
the current item, the one most recently returned by a call on next(); or null, if next() has not been called, or if the end of the sequence has been reached.

position

public int position()
Get the current position. This will be zero before the first call on next(), otherwise it will be the number of times that next() has been called.

Specified by:
position in interface SequenceIterator<Item>
Returns:
the current position, the position of the item returned by the most recent call of next()

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.

(Currently, closing an iterator is important only 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 interface SequenceIterator<Item>

getAnother

public BlockIterator getAnother()
                         throws XPathException
Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.

Specified by:
getAnother in interface SequenceIterator<Item>
Returns:
a SequenceIterator that iterates over the same items, positioned before the first item
Throws:
XPathException - if any error occurs

getProperties

public int getProperties()
Get properties of this iterator, as a bit-significant integer.

Specified by:
getProperties in interface SequenceIterator<Item>
Returns:
the properties of this iterator. This will be some combination of properties such as SequenceIterator.GROUNDED, SequenceIterator.LAST_POSITION_FINDER, and SequenceIterator.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.


Copyright (c) 2004-2011 Saxonica Limited. All rights reserved.