Package net.sf.saxon.tree.iter

Class SingleNodeIterator

java.lang.Object
net.sf.saxon.tree.iter.SingleNodeIterator
All Implemented Interfaces:
Closeable, AutoCloseable, LastPositionFinder, SequenceIterator<NodeInfo>, AxisIterator, GroundedIterator<NodeInfo>, LookaheadIterator<NodeInfo>, ReversibleIterator<NodeInfo>, UnfailingIterator<NodeInfo>
public class SingleNodeIterator extends Object implements AxisIterator, ReversibleIterator<NodeInfo>, LastPositionFinder, GroundedIterator<NodeInfo>, LookaheadIterator<NodeInfo>
SingleNodeIterator: an iterator over a sequence of zero or one nodes

  • Method Details

    • makeIterator

      public static AxisIterator makeIterator(NodeInfo item)
      Factory method.
      Parameters:
      item - the item to iterate over
      Returns:
      a SingletonIterator over the supplied item, or an EmptyIterator if the supplied item is null.

    • 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.
      Specified by:
      hasNext in interface LookaheadIterator<NodeInfo>
      Returns:
      true if there are more items

    • next

      public NodeInfo next()
      Description copied from interface: UnfailingIterator
      Get the next item in the sequence.
      Specified by:
      next in interface AxisIterator
      Specified by:
      next in interface SequenceIterator<NodeInfo>
      Specified by:
      next in interface UnfailingIterator<NodeInfo>
      Returns:
      the next Item. If there are no more items, return null.

    • 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 the result of getProperties() on the iterator includes the bit setting SequenceIterator.LAST_POSITION_FINDER
      Specified by:
      getLength in interface LastPositionFinder
      Returns:
      the number of items in the sequence

    • 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 interface AutoCloseable
      Specified by:
      close in interface Closeable
      Specified by:
      close in interface SequenceIterator<NodeInfo>

    • getReverseIterator

      public SequenceIterator<NodeInfo> getReverseIterator()
      Description copied from interface: ReversibleIterator
      Get a new SequenceIterator that returns the same items in reverse order. If this SequenceIterator is an AxisIterator, then the returned SequenceIterator must also be an AxisIterator.
      Specified by:
      getReverseIterator in interface ReversibleIterator<NodeInfo>
      Returns:
      an iterator over the items in reverse order

    • getValue

      public NodeInfo getValue()

    • materialize

      public GroundedValue<NodeInfo> materialize()
      Return a Value containing all the items in the sequence returned by this SequenceIterator
      Specified by:
      materialize in interface GroundedIterator<NodeInfo>
      Specified by:
      materialize in interface SequenceIterator<NodeInfo>
      Returns:
      the corresponding Value. If the value is a closure or a function call package, it will be evaluated and expanded.

    • getResidue

      public GroundedValue<NodeInfo> getResidue() throws XPathException
      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 interface GroundedIterator<NodeInfo>
      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

      public int getProperties()
      Get properties of this iterator, as a bit-significant integer.
      Specified by:
      getProperties in interface SequenceIterator<NodeInfo>
      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.