Class SingletonIterator

java.lang.Object
net.sf.saxon.om.SingletonIterator
All Implemented Interfaces:
LastPositionFinder, ReversibleIterator, AtomizableIterator, AxisIterator, GroundedIterator, LookaheadIterator, SequenceIterator

SingletonIterator: an iterator over a sequence of zero or one values
  • Method Details

    • makeIterator

      public static AxisIterator makeIterator(Item 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
      Returns:
      true if there are more items
    • next

      public Item next()
      Description copied from interface: AxisIterator
      Get the next item in the sequence.
      Specified by:
      next in interface AxisIterator
      Specified by:
      next in interface SequenceIterator
      Returns:
      the next Item. If there are no more nodes, return null.
    • current

      public Item current()
      Description copied from interface: AxisIterator
      Get the current item in the sequence.
      Specified by:
      current in interface AxisIterator
      Specified by:
      current in interface SequenceIterator
      Returns:
      the current item, that is, the item most recently returned by next()
    • position

      public int position()
      Return the current position in the sequence.
      Specified by:
      position in interface AxisIterator
      Specified by:
      position in interface SequenceIterator
      Returns:
      0 before the first call on next(); 1 before the second call on next(); -1 after the second call on next().
    • getLastPosition

      public int getLastPosition()
      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:
      getLastPosition in interface LastPositionFinder
    • getAnother

      public SequenceIterator getAnother()
      Description copied from interface: AxisIterator
      Get another iterator over the same sequence of items, positioned at the start of the sequence. It must be possible to call this method at any time, whether none, some, or all of the items in the original iterator have been read. The method is non-destructive: it does not change the state of the original iterator.
      Specified by:
      getAnother in interface AxisIterator
      Specified by:
      getAnother in interface SequenceIterator
      Returns:
      a new iterator over the same sequence
    • getReverseIterator

      public SequenceIterator 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
    • getValue

      public Item getValue()
    • materialize

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

      public void setIsAtomizing(boolean atomizing)
      Indicate that any nodes returned in the sequence will be atomized. This means that if it wishes to do so, the implementation can return the typed values of the nodes rather than the nodes themselves. The implementation is free to ignore this hint.

      This implementation attempts atomization of a singleton node if it is untyped. This avoids adding an iterator to iterate over the value in the common case where the typed value of the node is a single atomic value.

      Specified by:
      setIsAtomizing in interface AtomizableIterator
      Parameters:
      atomizing - true if the caller of this iterator will atomize any nodes that are returned, and is therefore willing to accept the typed value of the nodes instead of the nodes themselves.
    • getProperties

      public int 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.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.